diff -r 8d0be6a9a809 -r d382dacfd73f rt/emul/compact/src/main/java/java/util/Collections.java
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/rt/emul/compact/src/main/java/java/util/Collections.java Tue Feb 26 16:54:16 2013 +0100
@@ -0,0 +1,3953 @@
+/*
+ * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.util;
+import java.io.Serializable;
+import java.io.IOException;
+import java.lang.reflect.Array;
+
+/**
+ * This class consists exclusively of static methods that operate on or return
+ * collections. It contains polymorphic algorithms that operate on
+ * collections, "wrappers", which return a new collection backed by a
+ * specified collection, and a few other odds and ends.
+ *
+ * The methods of this class all throw a NullPointerException
+ * if the collections or class objects provided to them are null.
+ *
+ *
The documentation for the polymorphic algorithms contained in this class
+ * generally includes a brief description of the implementation. Such
+ * descriptions should be regarded as implementation notes, rather than
+ * parts of the specification. Implementors should feel free to
+ * substitute other algorithms, so long as the specification itself is adhered
+ * to. (For example, the algorithm used by sort does not have to be
+ * a mergesort, but it does have to be stable.)
+ *
+ *
The "destructive" algorithms contained in this class, that is, the
+ * algorithms that modify the collection on which they operate, are specified
+ * to throw UnsupportedOperationException if the collection does not
+ * support the appropriate mutation primitive(s), such as the set
+ * method. These algorithms may, but are not required to, throw this
+ * exception if an invocation would have no effect on the collection. For
+ * example, invoking the sort method on an unmodifiable list that is
+ * already sorted may or may not throw UnsupportedOperationException.
+ *
+ *
This class is a member of the
+ *
+ * Java Collections Framework.
+ *
+ * @author Josh Bloch
+ * @author Neal Gafter
+ * @see Collection
+ * @see Set
+ * @see List
+ * @see Map
+ * @since 1.2
+ */
+
+public class Collections {
+ // Suppresses default constructor, ensuring non-instantiability.
+ private Collections() {
+ }
+
+ // Algorithms
+
+ /*
+ * Tuning parameters for algorithms - Many of the List algorithms have
+ * two implementations, one of which is appropriate for RandomAccess
+ * lists, the other for "sequential." Often, the random access variant
+ * yields better performance on small sequential access lists. The
+ * tuning parameters below determine the cutoff point for what constitutes
+ * a "small" sequential access list for each algorithm. The values below
+ * were empirically determined to work well for LinkedList. Hopefully
+ * they should be reasonable for other sequential access List
+ * implementations. Those doing performance work on this code would
+ * do well to validate the values of these parameters from time to time.
+ * (The first word of each tuning parameter name is the algorithm to which
+ * it applies.)
+ */
+ private static final int BINARYSEARCH_THRESHOLD = 5000;
+ private static final int REVERSE_THRESHOLD = 18;
+ private static final int SHUFFLE_THRESHOLD = 5;
+ private static final int FILL_THRESHOLD = 25;
+ private static final int ROTATE_THRESHOLD = 100;
+ private static final int COPY_THRESHOLD = 10;
+ private static final int REPLACEALL_THRESHOLD = 11;
+ private static final int INDEXOFSUBLIST_THRESHOLD = 35;
+
+ /**
+ * Sorts the specified list into ascending order, according to the
+ * {@linkplain Comparable natural ordering} of its elements.
+ * All elements in the list must implement the {@link Comparable}
+ * interface. Furthermore, all elements in the list must be
+ * mutually comparable (that is, {@code e1.compareTo(e2)}
+ * must not throw a {@code ClassCastException} for any elements
+ * {@code e1} and {@code e2} in the list).
+ *
+ *
This sort is guaranteed to be stable: equal elements will
+ * not be reordered as a result of the sort.
+ *
+ *
The specified list must be modifiable, but need not be resizable.
+ *
+ *
Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
+ *
+ *
The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
+ *
+ *
The implementation was adapted from Tim Peters's list sort for Python
+ * (
+ * TimSort). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
+ *
+ *
This implementation dumps the specified list into an array, sorts
+ * the array, and iterates over the list resetting each element
+ * from the corresponding position in the array. This avoids the
+ * n2 log(n) performance that would result from attempting
+ * to sort a linked list in place.
+ *
+ * @param list the list to be sorted.
+ * @throws ClassCastException if the list contains elements that are not
+ * mutually comparable (for example, strings and integers).
+ * @throws UnsupportedOperationException if the specified list's
+ * list-iterator does not support the {@code set} operation.
+ * @throws IllegalArgumentException (optional) if the implementation
+ * detects that the natural ordering of the list elements is
+ * found to violate the {@link Comparable} contract
+ */
+ public static > void sort(List list) {
+ Object[] a = list.toArray();
+ Arrays.sort(a);
+ ListIterator i = list.listIterator();
+ for (int j=0; jmutually
+ * comparable using the specified comparator (that is,
+ * {@code c.compare(e1, e2)} must not throw a {@code ClassCastException}
+ * for any elements {@code e1} and {@code e2} in the list).
+ *
+ * This sort is guaranteed to be stable: equal elements will
+ * not be reordered as a result of the sort.
+ *
+ *
The specified list must be modifiable, but need not be resizable.
+ *
+ *
Implementation note: This implementation is a stable, adaptive,
+ * iterative mergesort that requires far fewer than n lg(n) comparisons
+ * when the input array is partially sorted, while offering the
+ * performance of a traditional mergesort when the input array is
+ * randomly ordered. If the input array is nearly sorted, the
+ * implementation requires approximately n comparisons. Temporary
+ * storage requirements vary from a small constant for nearly sorted
+ * input arrays to n/2 object references for randomly ordered input
+ * arrays.
+ *
+ *
The implementation takes equal advantage of ascending and
+ * descending order in its input array, and can take advantage of
+ * ascending and descending order in different parts of the same
+ * input array. It is well-suited to merging two or more sorted arrays:
+ * simply concatenate the arrays and sort the resulting array.
+ *
+ *
The implementation was adapted from Tim Peters's list sort for Python
+ * (
+ * TimSort). It uses techiques from Peter McIlroy's "Optimistic
+ * Sorting and Information Theoretic Complexity", in Proceedings of the
+ * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
+ * January 1993.
+ *
+ *
This implementation dumps the specified list into an array, sorts
+ * the array, and iterates over the list resetting each element
+ * from the corresponding position in the array. This avoids the
+ * n2 log(n) performance that would result from attempting
+ * to sort a linked list in place.
+ *
+ * @param list the list to be sorted.
+ * @param c the comparator to determine the order of the list. A
+ * {@code null} value indicates that the elements' natural
+ * ordering should be used.
+ * @throws ClassCastException if the list contains elements that are not
+ * mutually comparable using the specified comparator.
+ * @throws UnsupportedOperationException if the specified list's
+ * list-iterator does not support the {@code set} operation.
+ * @throws IllegalArgumentException (optional) if the comparator is
+ * found to violate the {@link Comparator} contract
+ */
+ public static void sort(List list, Comparator c) {
+ Object[] a = list.toArray();
+ Arrays.sort(a, (Comparator)c);
+ ListIterator i = list.listIterator();
+ for (int j=0; jThis method runs in log(n) time for a "random access" list (which
+ * provides near-constant-time positional access). If the specified list
+ * does not implement the {@link RandomAccess} interface and is large,
+ * this method will do an iterator-based binary search that performs
+ * O(n) link traversals and O(log n) element comparisons.
+ *
+ * @param list the list to be searched.
+ * @param key the key to be searched for.
+ * @return the index of the search key, if it is contained in the list;
+ * otherwise, (-(insertion point) - 1). The
+ * insertion point is defined as the point at which the
+ * key would be inserted into the list: the index of the first
+ * element greater than the key, or list.size() if all
+ * elements in the list are less than the specified key. Note
+ * that this guarantees that the return value will be >= 0 if
+ * and only if the key is found.
+ * @throws ClassCastException if the list contains elements that are not
+ * mutually comparable (for example, strings and
+ * integers), or the search key is not mutually comparable
+ * with the elements of the list.
+ */
+ public static
+ int binarySearch(List> list, T key) {
+ if (list instanceof RandomAccess || list.size()
+ int indexedBinarySearch(List> list, T key)
+ {
+ int low = 0;
+ int high = list.size()-1;
+
+ while (low <= high) {
+ int mid = (low + high) >>> 1;
+ Comparable midVal = list.get(mid);
+ int cmp = midVal.compareTo(key);
+
+ if (cmp < 0)
+ low = mid + 1;
+ else if (cmp > 0)
+ high = mid - 1;
+ else
+ return mid; // key found
+ }
+ return -(low + 1); // key not found
+ }
+
+ private static
+ int iteratorBinarySearch(List> list, T key)
+ {
+ int low = 0;
+ int high = list.size()-1;
+ ListIterator> i = list.listIterator();
+
+ while (low <= high) {
+ int mid = (low + high) >>> 1;
+ Comparable midVal = get(i, mid);
+ int cmp = midVal.compareTo(key);
+
+ if (cmp < 0)
+ low = mid + 1;
+ else if (cmp > 0)
+ high = mid - 1;
+ else
+ return mid; // key found
+ }
+ return -(low + 1); // key not found
+ }
+
+ /**
+ * Gets the ith element from the given list by repositioning the specified
+ * list listIterator.
+ */
+ private static T get(ListIterator i, int index) {
+ T obj = null;
+ int pos = i.nextIndex();
+ if (pos <= index) {
+ do {
+ obj = i.next();
+ } while (pos++ < index);
+ } else {
+ do {
+ obj = i.previous();
+ } while (--pos > index);
+ }
+ return obj;
+ }
+
+ /**
+ * Searches the specified list for the specified object using the binary
+ * search algorithm. The list must be sorted into ascending order
+ * according to the specified comparator (as by the
+ * {@link #sort(List, Comparator) sort(List, Comparator)}
+ * method), prior to making this call. If it is
+ * not sorted, the results are undefined. If the list contains multiple
+ * elements equal to the specified object, there is no guarantee which one
+ * will be found.
+ *
+ * This method runs in log(n) time for a "random access" list (which
+ * provides near-constant-time positional access). If the specified list
+ * does not implement the {@link RandomAccess} interface and is large,
+ * this method will do an iterator-based binary search that performs
+ * O(n) link traversals and O(log n) element comparisons.
+ *
+ * @param list the list to be searched.
+ * @param key the key to be searched for.
+ * @param c the comparator by which the list is ordered.
+ * A null value indicates that the elements'
+ * {@linkplain Comparable natural ordering} should be used.
+ * @return the index of the search key, if it is contained in the list;
+ * otherwise, (-(insertion point) - 1). The
+ * insertion point is defined as the point at which the
+ * key would be inserted into the list: the index of the first
+ * element greater than the key, or list.size() if all
+ * elements in the list are less than the specified key. Note
+ * that this guarantees that the return value will be >= 0 if
+ * and only if the key is found.
+ * @throws ClassCastException if the list contains elements that are not
+ * mutually comparable using the specified comparator,
+ * or the search key is not mutually comparable with the
+ * elements of the list using this comparator.
+ */
+ public static int binarySearch(List list, T key, Comparator c) {
+ if (c==null)
+ return binarySearch((List) list, key);
+
+ if (list instanceof RandomAccess || list.size() int indexedBinarySearch(List l, T key, Comparator c) {
+ int low = 0;
+ int high = l.size()-1;
+
+ while (low <= high) {
+ int mid = (low + high) >>> 1;
+ T midVal = l.get(mid);
+ int cmp = c.compare(midVal, key);
+
+ if (cmp < 0)
+ low = mid + 1;
+ else if (cmp > 0)
+ high = mid - 1;
+ else
+ return mid; // key found
+ }
+ return -(low + 1); // key not found
+ }
+
+ private static int iteratorBinarySearch(List l, T key, Comparator c) {
+ int low = 0;
+ int high = l.size()-1;
+ ListIterator i = l.listIterator();
+
+ while (low <= high) {
+ int mid = (low + high) >>> 1;
+ T midVal = get(i, mid);
+ int cmp = c.compare(midVal, key);
+
+ if (cmp < 0)
+ low = mid + 1;
+ else if (cmp > 0)
+ high = mid - 1;
+ else
+ return mid; // key found
+ }
+ return -(low + 1); // key not found
+ }
+
+ private interface SelfComparable extends Comparable {}
+
+
+ /**
+ * Reverses the order of the elements in the specified list.
+ *
+ * This method runs in linear time.
+ *
+ * @param list the list whose elements are to be reversed.
+ * @throws UnsupportedOperationException if the specified list or
+ * its list-iterator does not support the set operation.
+ */
+ public static void reverse(List list) {
+ int size = list.size();
+ if (size < REVERSE_THRESHOLD || list instanceof RandomAccess) {
+ for (int i=0, mid=size>>1, j=size-1; i>1; i
+ *
+ * The hedge "approximately" is used in the foregoing description because
+ * default source of randomness is only approximately an unbiased source
+ * of independently chosen bits. If it were a perfect source of randomly
+ * chosen bits, then the algorithm would choose permutations with perfect
+ * uniformity.
+ *
+ * This implementation traverses the list backwards, from the last element
+ * up to the second, repeatedly swapping a randomly selected element into
+ * the "current position". Elements are randomly selected from the
+ * portion of the list that runs from the first element to the current
+ * position, inclusive.
+ *
+ * This method runs in linear time. If the specified list does not
+ * implement the {@link RandomAccess} interface and is large, this
+ * implementation dumps the specified list into an array before shuffling
+ * it, and dumps the shuffled array back into the list. This avoids the
+ * quadratic behavior that would result from shuffling a "sequential
+ * access" list in place.
+ *
+ * @param list the list to be shuffled.
+ * @throws UnsupportedOperationException if the specified list or
+ * its list-iterator does not support the set operation.
+ */
+ public static void shuffle(List list) {
+ Random rnd = r;
+ if (rnd == null)
+ r = rnd = new Random();
+ shuffle(list, rnd);
+ }
+ private static Random r;
+
+ /**
+ * Randomly permute the specified list using the specified source of
+ * randomness. All permutations occur with equal likelihood
+ * assuming that the source of randomness is fair.
+ *
+ * This implementation traverses the list backwards, from the last element
+ * up to the second, repeatedly swapping a randomly selected element into
+ * the "current position". Elements are randomly selected from the
+ * portion of the list that runs from the first element to the current
+ * position, inclusive.
+ *
+ * This method runs in linear time. If the specified list does not
+ * implement the {@link RandomAccess} interface and is large, this
+ * implementation dumps the specified list into an array before shuffling
+ * it, and dumps the shuffled array back into the list. This avoids the
+ * quadratic behavior that would result from shuffling a "sequential
+ * access" list in place.
+ *
+ * @param list the list to be shuffled.
+ * @param rnd the source of randomness to use to shuffle the list.
+ * @throws UnsupportedOperationException if the specified list or its
+ * list-iterator does not support the set operation.
+ */
+ public static void shuffle(List list, Random rnd) {
+ int size = list.size();
+ if (size < SHUFFLE_THRESHOLD || list instanceof RandomAccess) {
+ for (int i=size; i>1; i--)
+ swap(list, i-1, rnd.nextInt(i));
+ } else {
+ Object arr[] = list.toArray();
+
+ // Shuffle array
+ for (int i=size; i>1; i--)
+ swap(arr, i-1, rnd.nextInt(i));
+
+ // Dump array back into list
+ ListIterator it = list.listIterator();
+ for (int i=0; ii or j
+ * is out of range (i < 0 || i >= list.size()
+ * || j < 0 || j >= list.size()).
+ * @since 1.4
+ */
+ public static void swap(List list, int i, int j) {
+ final List l = list;
+ l.set(i, l.set(j, l.get(i)));
+ }
+
+ /**
+ * Swaps the two specified elements in the specified array.
+ */
+ private static void swap(Object[] arr, int i, int j) {
+ Object tmp = arr[i];
+ arr[i] = arr[j];
+ arr[j] = tmp;
+ }
+
+ /**
+ * Replaces all of the elements of the specified list with the specified
+ * element.
+ *
+ * This method runs in linear time.
+ *
+ * @param list the list to be filled with the specified element.
+ * @param obj The element with which to fill the specified list.
+ * @throws UnsupportedOperationException if the specified list or its
+ * list-iterator does not support the set operation.
+ */
+ public static void fill(List list, T obj) {
+ int size = list.size();
+
+ if (size < FILL_THRESHOLD || list instanceof RandomAccess) {
+ for (int i=0; i itr = list.listIterator();
+ for (int i=0; i
+ *
+ * This method runs in linear time.
+ *
+ * @param dest The destination list.
+ * @param src The source list.
+ * @throws IndexOutOfBoundsException if the destination list is too small
+ * to contain the entire source List.
+ * @throws UnsupportedOperationException if the destination list's
+ * list-iterator does not support the set operation.
+ */
+ public static void copy(List dest, List src) {
+ int srcSize = src.size();
+ if (srcSize > dest.size())
+ throw new IndexOutOfBoundsException("Source does not fit in dest");
+
+ if (srcSize < COPY_THRESHOLD ||
+ (src instanceof RandomAccess && dest instanceof RandomAccess)) {
+ for (int i=0; i di=dest.listIterator();
+ ListIterator si=src.listIterator();
+ for (int i=0; inatural ordering of its elements. All elements in the
+ * collection must implement the Comparable interface.
+ * Furthermore, all elements in the collection must be mutually
+ * comparable (that is, e1.compareTo(e2) must not throw a
+ * ClassCastException for any elements e1 and
+ * e2 in the collection).
+ *
+ * This method iterates over the entire collection, hence it requires
+ * time proportional to the size of the collection.
+ *
+ * @param coll the collection whose minimum element is to be determined.
+ * @return the minimum element of the given collection, according
+ * to the natural ordering of its elements.
+ * @throws ClassCastException if the collection contains elements that are
+ * not mutually comparable (for example, strings and
+ * integers).
+ * @throws NoSuchElementException if the collection is empty.
+ * @see Comparable
+ */
+ public static > T min(Collection coll) {
+ Iterator i = coll.iterator();
+ T candidate = i.next();
+
+ while (i.hasNext()) {
+ T next = i.next();
+ if (next.compareTo(candidate) < 0)
+ candidate = next;
+ }
+ return candidate;
+ }
+
+ /**
+ * Returns the minimum element of the given collection, according to the
+ * order induced by the specified comparator. All elements in the
+ * collection must be mutually comparable by the specified
+ * comparator (that is, comp.compare(e1, e2) must not throw a
+ * ClassCastException for any elements e1 and
+ * e2 in the collection).
+ *
+ * This method iterates over the entire collection, hence it requires
+ * time proportional to the size of the collection.
+ *
+ * @param coll the collection whose minimum element is to be determined.
+ * @param comp the comparator with which to determine the minimum element.
+ * A null value indicates that the elements' natural
+ * ordering should be used.
+ * @return the minimum element of the given collection, according
+ * to the specified comparator.
+ * @throws ClassCastException if the collection contains elements that are
+ * not mutually comparable using the specified comparator.
+ * @throws NoSuchElementException if the collection is empty.
+ * @see Comparable
+ */
+ public static T min(Collection coll, Comparator comp) {
+ if (comp==null)
+ return (T)min((Collection) (Collection) coll);
+
+ Iterator i = coll.iterator();
+ T candidate = i.next();
+
+ while (i.hasNext()) {
+ T next = i.next();
+ if (comp.compare(next, candidate) < 0)
+ candidate = next;
+ }
+ return candidate;
+ }
+
+ /**
+ * Returns the maximum element of the given collection, according to the
+ * natural ordering of its elements. All elements in the
+ * collection must implement the Comparable interface.
+ * Furthermore, all elements in the collection must be mutually
+ * comparable (that is, e1.compareTo(e2) must not throw a
+ * ClassCastException for any elements e1 and
+ * e2 in the collection).
+ *
+ * This method iterates over the entire collection, hence it requires
+ * time proportional to the size of the collection.
+ *
+ * @param coll the collection whose maximum element is to be determined.
+ * @return the maximum element of the given collection, according
+ * to the natural ordering of its elements.
+ * @throws ClassCastException if the collection contains elements that are
+ * not mutually comparable (for example, strings and
+ * integers).
+ * @throws NoSuchElementException if the collection is empty.
+ * @see Comparable
+ */
+ public static > T max(Collection coll) {
+ Iterator i = coll.iterator();
+ T candidate = i.next();
+
+ while (i.hasNext()) {
+ T next = i.next();
+ if (next.compareTo(candidate) > 0)
+ candidate = next;
+ }
+ return candidate;
+ }
+
+ /**
+ * Returns the maximum element of the given collection, according to the
+ * order induced by the specified comparator. All elements in the
+ * collection must be mutually comparable by the specified
+ * comparator (that is, comp.compare(e1, e2) must not throw a
+ * ClassCastException for any elements e1 and
+ * e2 in the collection).
+ *
+ * This method iterates over the entire collection, hence it requires
+ * time proportional to the size of the collection.
+ *
+ * @param coll the collection whose maximum element is to be determined.
+ * @param comp the comparator with which to determine the maximum element.
+ * A null value indicates that the elements' natural
+ * ordering should be used.
+ * @return the maximum element of the given collection, according
+ * to the specified comparator.
+ * @throws ClassCastException if the collection contains elements that are
+ * not mutually comparable using the specified comparator.
+ * @throws NoSuchElementException if the collection is empty.
+ * @see Comparable
+ */
+ public static T max(Collection coll, Comparator comp) {
+ if (comp==null)
+ return (T)max((Collection) (Collection) coll);
+
+ Iterator i = coll.iterator();
+ T candidate = i.next();
+
+ while (i.hasNext()) {
+ T next = i.next();
+ if (comp.compare(next, candidate) > 0)
+ candidate = next;
+ }
+ return candidate;
+ }
+
+ /**
+ * Rotates the elements in the specified list by the specified distance.
+ * After calling this method, the element at index i will be
+ * the element previously at index (i - distance) mod
+ * list.size(), for all values of i between 0
+ * and list.size()-1, inclusive. (This method has no effect on
+ * the size of the list.)
+ *
+ * For example, suppose list comprises [t, a, n, k, s].
+ * After invoking Collections.rotate(list, 1) (or
+ * Collections.rotate(list, -4)), list will comprise
+ * [s, t, a, n, k].
+ *
+ *
Note that this method can usefully be applied to sublists to
+ * move one or more elements within a list while preserving the
+ * order of the remaining elements. For example, the following idiom
+ * moves the element at index j forward to position
+ * k (which must be greater than or equal to j):
+ *
+ * Collections.rotate(list.subList(j, k+1), -1);
+ *
+ * To make this concrete, suppose list comprises
+ * [a, b, c, d, e]. To move the element at index 1
+ * (b) forward two positions, perform the following invocation:
+ *
+ * Collections.rotate(l.subList(1, 4), -1);
+ *
+ * The resulting list is [a, c, d, b, e].
+ *
+ * To move more than one element forward, increase the absolute value
+ * of the rotation distance. To move elements backward, use a positive
+ * shift distance.
+ *
+ *
If the specified list is small or implements the {@link
+ * RandomAccess} interface, this implementation exchanges the first
+ * element into the location it should go, and then repeatedly exchanges
+ * the displaced element into the location it should go until a displaced
+ * element is swapped into the first element. If necessary, the process
+ * is repeated on the second and successive elements, until the rotation
+ * is complete. If the specified list is large and doesn't implement the
+ * RandomAccess interface, this implementation breaks the
+ * list into two sublist views around index -distance mod size.
+ * Then the {@link #reverse(List)} method is invoked on each sublist view,
+ * and finally it is invoked on the entire list. For a more complete
+ * description of both algorithms, see Section 2.3 of Jon Bentley's
+ * Programming Pearls (Addison-Wesley, 1986).
+ *
+ * @param list the list to be rotated.
+ * @param distance the distance to rotate the list. There are no
+ * constraints on this value; it may be zero, negative, or
+ * greater than list.size().
+ * @throws UnsupportedOperationException if the specified list or
+ * its list-iterator does not support the set operation.
+ * @since 1.4
+ */
+ public static void rotate(List list, int distance) {
+ if (list instanceof RandomAccess || list.size() < ROTATE_THRESHOLD)
+ rotate1(list, distance);
+ else
+ rotate2(list, distance);
+ }
+
+ private static void rotate1(List list, int distance) {
+ int size = list.size();
+ if (size == 0)
+ return;
+ distance = distance % size;
+ if (distance < 0)
+ distance += size;
+ if (distance == 0)
+ return;
+
+ for (int cycleStart = 0, nMoved = 0; nMoved != size; cycleStart++) {
+ T displaced = list.get(cycleStart);
+ int i = cycleStart;
+ do {
+ i += distance;
+ if (i >= size)
+ i -= size;
+ displaced = list.set(i, displaced);
+ nMoved ++;
+ } while (i != cycleStart);
+ }
+ }
+
+ private static void rotate2(List list, int distance) {
+ int size = list.size();
+ if (size == 0)
+ return;
+ int mid = -distance % size;
+ if (mid < 0)
+ mid += size;
+ if (mid == 0)
+ return;
+
+ reverse(list.subList(0, mid));
+ reverse(list.subList(mid, size));
+ reverse(list);
+ }
+
+ /**
+ * Replaces all occurrences of one specified value in a list with another.
+ * More formally, replaces with newVal each element e
+ * in list such that
+ * (oldVal==null ? e==null : oldVal.equals(e)).
+ * (This method has no effect on the size of the list.)
+ *
+ * @param list the list in which replacement is to occur.
+ * @param oldVal the old value to be replaced.
+ * @param newVal the new value with which oldVal is to be
+ * replaced.
+ * @return true if list contained one or more elements
+ * e such that
+ * (oldVal==null ? e==null : oldVal.equals(e)).
+ * @throws UnsupportedOperationException if the specified list or
+ * its list-iterator does not support the set operation.
+ * @since 1.4
+ */
+ public static boolean replaceAll(List list, T oldVal, T newVal) {
+ boolean result = false;
+ int size = list.size();
+ if (size < REPLACEALL_THRESHOLD || list instanceof RandomAccess) {
+ if (oldVal==null) {
+ for (int i=0; i itr=list.listIterator();
+ if (oldVal==null) {
+ for (int i=0; ii
+ * such that source.subList(i, i+target.size()).equals(target),
+ * or -1 if there is no such index. (Returns -1 if
+ * target.size() > source.size().)
+ *
+ * This implementation uses the "brute force" technique of scanning
+ * over the source list, looking for a match with the target at each
+ * location in turn.
+ *
+ * @param source the list in which to search for the first occurrence
+ * of target.
+ * @param target the list to search for as a subList of source.
+ * @return the starting position of the first occurrence of the specified
+ * target list within the specified source list, or -1 if there
+ * is no such occurrence.
+ * @since 1.4
+ */
+ public static int indexOfSubList(List source, List target) {
+ int sourceSize = source.size();
+ int targetSize = target.size();
+ int maxCandidate = sourceSize - targetSize;
+
+ if (sourceSize < INDEXOFSUBLIST_THRESHOLD ||
+ (source instanceof RandomAccess&&target instanceof RandomAccess)) {
+ nextCand:
+ for (int candidate = 0; candidate <= maxCandidate; candidate++) {
+ for (int i=0, j=candidate; i si = source.listIterator();
+ nextCand:
+ for (int candidate = 0; candidate <= maxCandidate; candidate++) {
+ ListIterator ti = target.listIterator();
+ for (int i=0; ii
+ * such that source.subList(i, i+target.size()).equals(target),
+ * or -1 if there is no such index. (Returns -1 if
+ * target.size() > source.size().)
+ *
+ * This implementation uses the "brute force" technique of iterating
+ * over the source list, looking for a match with the target at each
+ * location in turn.
+ *
+ * @param source the list in which to search for the last occurrence
+ * of target.
+ * @param target the list to search for as a subList of source.
+ * @return the starting position of the last occurrence of the specified
+ * target list within the specified source list, or -1 if there
+ * is no such occurrence.
+ * @since 1.4
+ */
+ public static int lastIndexOfSubList(List source, List target) {
+ int sourceSize = source.size();
+ int targetSize = target.size();
+ int maxCandidate = sourceSize - targetSize;
+
+ if (sourceSize < INDEXOFSUBLIST_THRESHOLD ||
+ source instanceof RandomAccess) { // Index access version
+ nextCand:
+ for (int candidate = maxCandidate; candidate >= 0; candidate--) {
+ for (int i=0, j=candidate; i si = source.listIterator(maxCandidate);
+ nextCand:
+ for (int candidate = maxCandidate; candidate >= 0; candidate--) {
+ ListIterator ti = target.listIterator();
+ for (int i=0; iUnsupportedOperationException.
+ *
+ * The returned collection does not pass the hashCode and equals
+ * operations through to the backing collection, but relies on
+ * Object's equals and hashCode methods. This
+ * is necessary to preserve the contracts of these operations in the case
+ * that the backing collection is a set or a list.
+ *
+ * The returned collection will be serializable if the specified collection
+ * is serializable.
+ *
+ * @param c the collection for which an unmodifiable view is to be
+ * returned.
+ * @return an unmodifiable view of the specified collection.
+ */
+ public static Collection unmodifiableCollection(Collection c) {
+ return new UnmodifiableCollection<>(c);
+ }
+
+ /**
+ * @serial include
+ */
+ static class UnmodifiableCollection implements Collection, Serializable {
+ private static final long serialVersionUID = 1820017752578914078L;
+
+ final Collection c;
+
+ UnmodifiableCollection(Collection c) {
+ if (c==null)
+ throw new NullPointerException();
+ this.c = c;
+ }
+
+ public int size() {return c.size();}
+ public boolean isEmpty() {return c.isEmpty();}
+ public boolean contains(Object o) {return c.contains(o);}
+ public Object[] toArray() {return c.toArray();}
+ public T[] toArray(T[] a) {return c.toArray(a);}
+ public String toString() {return c.toString();}
+
+ public Iterator iterator() {
+ return new Iterator() {
+ private final Iterator i = c.iterator();
+
+ public boolean hasNext() {return i.hasNext();}
+ public E next() {return i.next();}
+ public void remove() {
+ throw new UnsupportedOperationException();
+ }
+ };
+ }
+
+ public boolean add(E e) {
+ throw new UnsupportedOperationException();
+ }
+ public boolean remove(Object o) {
+ throw new UnsupportedOperationException();
+ }
+
+ public boolean containsAll(Collection coll) {
+ return c.containsAll(coll);
+ }
+ public boolean addAll(Collection coll) {
+ throw new UnsupportedOperationException();
+ }
+ public boolean removeAll(Collection coll) {
+ throw new UnsupportedOperationException();
+ }
+ public boolean retainAll(Collection coll) {
+ throw new UnsupportedOperationException();
+ }
+ public void clear() {
+ throw new UnsupportedOperationException();
+ }
+ }
+
+ /**
+ * Returns an unmodifiable view of the specified set. This method allows
+ * modules to provide users with "read-only" access to internal sets.
+ * Query operations on the returned set "read through" to the specified
+ * set, and attempts to modify the returned set, whether direct or via its
+ * iterator, result in an UnsupportedOperationException.
+ *
+ * The returned set will be serializable if the specified set
+ * is serializable.
+ *
+ * @param s the set for which an unmodifiable view is to be returned.
+ * @return an unmodifiable view of the specified set.
+ */
+ public static Set unmodifiableSet(Set s) {
+ return new UnmodifiableSet<>(s);
+ }
+
+ /**
+ * @serial include
+ */
+ static class UnmodifiableSet extends UnmodifiableCollection
+ implements Set, Serializable {
+ private static final long serialVersionUID = -9215047833775013803L;
+
+ UnmodifiableSet(Set s) {super(s);}
+ public boolean equals(Object o) {return o == this || c.equals(o);}
+ public int hashCode() {return c.hashCode();}
+ }
+
+ /**
+ * Returns an unmodifiable view of the specified sorted set. This method
+ * allows modules to provide users with "read-only" access to internal
+ * sorted sets. Query operations on the returned sorted set "read
+ * through" to the specified sorted set. Attempts to modify the returned
+ * sorted set, whether direct, via its iterator, or via its
+ * subSet, headSet, or tailSet views, result in
+ * an UnsupportedOperationException.
+ *
+ * The returned sorted set will be serializable if the specified sorted set
+ * is serializable.
+ *
+ * @param s the sorted set for which an unmodifiable view is to be
+ * returned.
+ * @return an unmodifiable view of the specified sorted set.
+ */
+ public static SortedSet unmodifiableSortedSet(SortedSet s) {
+ return new UnmodifiableSortedSet<>(s);
+ }
+
+ /**
+ * @serial include
+ */
+ static class UnmodifiableSortedSet
+ extends UnmodifiableSet
+ implements SortedSet, Serializable {
+ private static final long serialVersionUID = -4929149591599911165L;
+ private final SortedSet ss;
+
+ UnmodifiableSortedSet(SortedSet s) {super(s); ss = s;}
+
+ public Comparator comparator() {return ss.comparator();}
+
+ public SortedSet subSet(E fromElement, E toElement) {
+ return new UnmodifiableSortedSet<>(ss.subSet(fromElement,toElement));
+ }
+ public SortedSet headSet(E toElement) {
+ return new UnmodifiableSortedSet<>(ss.headSet(toElement));
+ }
+ public SortedSet tailSet(E fromElement) {
+ return new UnmodifiableSortedSet<>(ss.tailSet(fromElement));
+ }
+
+ public E first() {return ss.first();}
+ public E last() {return ss.last();}
+ }
+
+ /**
+ * Returns an unmodifiable view of the specified list. This method allows
+ * modules to provide users with "read-only" access to internal
+ * lists. Query operations on the returned list "read through" to the
+ * specified list, and attempts to modify the returned list, whether
+ * direct or via its iterator, result in an
+ * UnsupportedOperationException.
+ *
+ * The returned list will be serializable if the specified list
+ * is serializable. Similarly, the returned list will implement
+ * {@link RandomAccess} if the specified list does.
+ *
+ * @param list the list for which an unmodifiable view is to be returned.
+ * @return an unmodifiable view of the specified list.
+ */
+ public static List unmodifiableList(List list) {
+ return (list instanceof RandomAccess ?
+ new UnmodifiableRandomAccessList<>(list) :
+ new UnmodifiableList<>(list));
+ }
+
+ /**
+ * @serial include
+ */
+ static class UnmodifiableList extends UnmodifiableCollection
+ implements List {
+ private static final long serialVersionUID = -283967356065247728L;
+ final List list;
+
+ UnmodifiableList(List list) {
+ super(list);
+ this.list = list;
+ }
+
+ public boolean equals(Object o) {return o == this || list.equals(o);}
+ public int hashCode() {return list.hashCode();}
+
+ public E get(int index) {return list.get(index);}
+ public E set(int index, E element) {
+ throw new UnsupportedOperationException();
+ }
+ public void add(int index, E element) {
+ throw new UnsupportedOperationException();
+ }
+ public E remove(int index) {
+ throw new UnsupportedOperationException();
+ }
+ public int indexOf(Object o) {return list.indexOf(o);}
+ public int lastIndexOf(Object o) {return list.lastIndexOf(o);}
+ public boolean addAll(int index, Collection c) {
+ throw new UnsupportedOperationException();
+ }
+ public ListIterator listIterator() {return listIterator(0);}
+
+ public ListIterator listIterator(final int index) {
+ return new ListIterator() {
+ private final ListIterator i
+ = list.listIterator(index);
+
+ public boolean hasNext() {return i.hasNext();}
+ public E next() {return i.next();}
+ public boolean hasPrevious() {return i.hasPrevious();}
+ public E previous() {return i.previous();}
+ public int nextIndex() {return i.nextIndex();}
+ public int previousIndex() {return i.previousIndex();}
+
+ public void remove() {
+ throw new UnsupportedOperationException();
+ }
+ public void set(E e) {
+ throw new UnsupportedOperationException();
+ }
+ public void add(E e) {
+ throw new UnsupportedOperationException();
+ }
+ };
+ }
+
+ public List subList(int fromIndex, int toIndex) {
+ return new UnmodifiableList<>(list.subList(fromIndex, toIndex));
+ }
+
+ /**
+ * UnmodifiableRandomAccessList instances are serialized as
+ * UnmodifiableList instances to allow them to be deserialized
+ * in pre-1.4 JREs (which do not have UnmodifiableRandomAccessList).
+ * This method inverts the transformation. As a beneficial
+ * side-effect, it also grafts the RandomAccess marker onto
+ * UnmodifiableList instances that were serialized in pre-1.4 JREs.
+ *
+ * Note: Unfortunately, UnmodifiableRandomAccessList instances
+ * serialized in 1.4.1 and deserialized in 1.4 will become
+ * UnmodifiableList instances, as this method was missing in 1.4.
+ */
+ private Object readResolve() {
+ return (list instanceof RandomAccess
+ ? new UnmodifiableRandomAccessList<>(list)
+ : this);
+ }
+ }
+
+ /**
+ * @serial include
+ */
+ static class UnmodifiableRandomAccessList extends UnmodifiableList
+ implements RandomAccess
+ {
+ UnmodifiableRandomAccessList(List list) {
+ super(list);
+ }
+
+ public List subList(int fromIndex, int toIndex) {
+ return new UnmodifiableRandomAccessList<>(
+ list.subList(fromIndex, toIndex));
+ }
+
+ private static final long serialVersionUID = -2542308836966382001L;
+
+ /**
+ * Allows instances to be deserialized in pre-1.4 JREs (which do
+ * not have UnmodifiableRandomAccessList). UnmodifiableList has
+ * a readResolve method that inverts this transformation upon
+ * deserialization.
+ */
+ private Object writeReplace() {
+ return new UnmodifiableList<>(list);
+ }
+ }
+
+ /**
+ * Returns an unmodifiable view of the specified map. This method
+ * allows modules to provide users with "read-only" access to internal
+ * maps. Query operations on the returned map "read through"
+ * to the specified map, and attempts to modify the returned
+ * map, whether direct or via its collection views, result in an
+ * UnsupportedOperationException.
+ *
+ * The returned map will be serializable if the specified map
+ * is serializable.
+ *
+ * @param m the map for which an unmodifiable view is to be returned.
+ * @return an unmodifiable view of the specified map.
+ */
+ public static Map unmodifiableMap(Map m) {
+ return new UnmodifiableMap<>(m);
+ }
+
+ /**
+ * @serial include
+ */
+ private static class UnmodifiableMap implements Map, Serializable {
+ private static final long serialVersionUID = -1034234728574286014L;
+
+ private final Map m;
+
+ UnmodifiableMap(Map m) {
+ if (m==null)
+ throw new NullPointerException();
+ this.m = m;
+ }
+
+ public int size() {return m.size();}
+ public boolean isEmpty() {return m.isEmpty();}
+ public boolean containsKey(Object key) {return m.containsKey(key);}
+ public boolean containsValue(Object val) {return m.containsValue(val);}
+ public V get(Object key) {return m.get(key);}
+
+ public V put(K key, V value) {
+ throw new UnsupportedOperationException();
+ }
+ public V remove(Object key) {
+ throw new UnsupportedOperationException();
+ }
+ public void putAll(Map m) {
+ throw new UnsupportedOperationException();
+ }
+ public void clear() {
+ throw new UnsupportedOperationException();
+ }
+
+ private transient Set keySet = null;
+ private transient Set> entrySet = null;
+ private transient Collection values = null;
+
+ public Set keySet() {
+ if (keySet==null)
+ keySet = unmodifiableSet(m.keySet());
+ return keySet;
+ }
+
+ public Set> entrySet() {
+ if (entrySet==null)
+ entrySet = new UnmodifiableEntrySet<>(m.entrySet());
+ return entrySet;
+ }
+
+ public Collection values() {
+ if (values==null)
+ values = unmodifiableCollection(m.values());
+ return values;
+ }
+
+ public boolean equals(Object o) {return o == this || m.equals(o);}
+ public int hashCode() {return m.hashCode();}
+ public String toString() {return m.toString();}
+
+ /**
+ * We need this class in addition to UnmodifiableSet as
+ * Map.Entries themselves permit modification of the backing Map
+ * via their setValue operation. This class is subtle: there are
+ * many possible attacks that must be thwarted.
+ *
+ * @serial include
+ */
+ static class UnmodifiableEntrySet
+ extends UnmodifiableSet> {
+ private static final long serialVersionUID = 7854390611657943733L;
+
+ UnmodifiableEntrySet(Set> s) {
+ super((Set)s);
+ }
+ public Iterator> iterator() {
+ return new Iterator>() {
+ private final Iterator> i = c.iterator();
+
+ public boolean hasNext() {
+ return i.hasNext();
+ }
+ public Map.Entry next() {
+ return new UnmodifiableEntry<>(i.next());
+ }
+ public void remove() {
+ throw new UnsupportedOperationException();
+ }
+ };
+ }
+
+ public Object[] toArray() {
+ Object[] a = c.toArray();
+ for (int i=0; i((Map.Entry)a[i]);
+ return a;
+ }
+
+ public T[] toArray(T[] a) {
+ // We don't pass a to c.toArray, to avoid window of
+ // vulnerability wherein an unscrupulous multithreaded client
+ // could get his hands on raw (unwrapped) Entries from c.
+ Object[] arr = c.toArray(a.length==0 ? a : Arrays.copyOf(a, 0));
+
+ for (int i=0; i((Map.Entry)arr[i]);
+
+ if (arr.length > a.length)
+ return (T[])arr;
+
+ System.arraycopy(arr, 0, a, 0, arr.length);
+ if (a.length > arr.length)
+ a[arr.length] = null;
+ return a;
+ }
+
+ /**
+ * This method is overridden to protect the backing set against
+ * an object with a nefarious equals function that senses
+ * that the equality-candidate is Map.Entry and calls its
+ * setValue method.
+ */
+ public boolean contains(Object o) {
+ if (!(o instanceof Map.Entry))
+ return false;
+ return c.contains(
+ new UnmodifiableEntry<>((Map.Entry) o));
+ }
+
+ /**
+ * The next two methods are overridden to protect against
+ * an unscrupulous List whose contains(Object o) method senses
+ * when o is a Map.Entry, and calls o.setValue.
+ */
+ public boolean containsAll(Collection coll) {
+ for (Object e : coll) {
+ if (!contains(e)) // Invokes safe contains() above
+ return false;
+ }
+ return true;
+ }
+ public boolean equals(Object o) {
+ if (o == this)
+ return true;
+
+ if (!(o instanceof Set))
+ return false;
+ Set s = (Set) o;
+ if (s.size() != c.size())
+ return false;
+ return containsAll(s); // Invokes safe containsAll() above
+ }
+
+ /**
+ * This "wrapper class" serves two purposes: it prevents
+ * the client from modifying the backing Map, by short-circuiting
+ * the setValue method, and it protects the backing Map against
+ * an ill-behaved Map.Entry that attempts to modify another
+ * Map Entry when asked to perform an equality check.
+ */
+ private static class UnmodifiableEntry implements Map.Entry {
+ private Map.Entry e;
+
+ UnmodifiableEntry(Map.Entry e) {this.e = e;}
+
+ public K getKey() {return e.getKey();}
+ public V getValue() {return e.getValue();}
+ public V setValue(V value) {
+ throw new UnsupportedOperationException();
+ }
+ public int hashCode() {return e.hashCode();}
+ public boolean equals(Object o) {
+ if (!(o instanceof Map.Entry))
+ return false;
+ Map.Entry t = (Map.Entry)o;
+ return eq(e.getKey(), t.getKey()) &&
+ eq(e.getValue(), t.getValue());
+ }
+ public String toString() {return e.toString();}
+ }
+ }
+ }
+
+ /**
+ * Returns an unmodifiable view of the specified sorted map. This method
+ * allows modules to provide users with "read-only" access to internal
+ * sorted maps. Query operations on the returned sorted map "read through"
+ * to the specified sorted map. Attempts to modify the returned
+ * sorted map, whether direct, via its collection views, or via its
+ * subMap, headMap, or tailMap views, result in
+ * an UnsupportedOperationException.
+ *
+ * The returned sorted map will be serializable if the specified sorted map
+ * is serializable.
+ *
+ * @param m the sorted map for which an unmodifiable view is to be
+ * returned.
+ * @return an unmodifiable view of the specified sorted map.
+ */
+ public static SortedMap unmodifiableSortedMap(SortedMap m) {
+ return new UnmodifiableSortedMap<>(m);
+ }
+
+ /**
+ * @serial include
+ */
+ static class UnmodifiableSortedMap
+ extends UnmodifiableMap
+ implements SortedMap, Serializable {
+ private static final long serialVersionUID = -8806743815996713206L;
+
+ private final SortedMap sm;
+
+ UnmodifiableSortedMap(SortedMap m) {super(m); sm = m;}
+
+ public Comparator comparator() {return sm.comparator();}
+
+ public SortedMap subMap(K fromKey, K toKey) {
+ return new UnmodifiableSortedMap<>(sm.subMap(fromKey, toKey));
+ }
+ public SortedMap headMap(K toKey) {
+ return new UnmodifiableSortedMap<>(sm.headMap(toKey));
+ }
+ public SortedMap tailMap(K fromKey) {
+ return new UnmodifiableSortedMap<>(sm.tailMap(fromKey));
+ }
+
+ public K firstKey() {return sm.firstKey();}
+ public K lastKey() {return sm.lastKey();}
+ }
+
+
+ // Synch Wrappers
+
+ /**
+ * Returns a synchronized (thread-safe) collection backed by the specified
+ * collection. In order to guarantee serial access, it is critical that
+ * all access to the backing collection is accomplished
+ * through the returned collection.
+ *
+ * It is imperative that the user manually synchronize on the returned
+ * collection when iterating over it:
+ *
+ * Collection c = Collections.synchronizedCollection(myCollection);
+ * ...
+ * synchronized (c) {
+ * Iterator i = c.iterator(); // Must be in the synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * Failure to follow this advice may result in non-deterministic behavior.
+ *
+ * The returned collection does not pass the hashCode
+ * and equals operations through to the backing collection, but
+ * relies on Object's equals and hashCode methods. This is
+ * necessary to preserve the contracts of these operations in the case
+ * that the backing collection is a set or a list.
+ *
+ * The returned collection will be serializable if the specified collection
+ * is serializable.
+ *
+ * @param c the collection to be "wrapped" in a synchronized collection.
+ * @return a synchronized view of the specified collection.
+ */
+ public static Collection synchronizedCollection(Collection c) {
+ return new SynchronizedCollection<>(c);
+ }
+
+ static Collection synchronizedCollection(Collection c, Object mutex) {
+ return new SynchronizedCollection<>(c, mutex);
+ }
+
+ /**
+ * @serial include
+ */
+ static class SynchronizedCollection implements Collection, Serializable {
+ private static final long serialVersionUID = 3053995032091335093L;
+
+ final Collection c; // Backing Collection
+ final Object mutex; // Object on which to synchronize
+
+ SynchronizedCollection(Collection c) {
+ if (c==null)
+ throw new NullPointerException();
+ this.c = c;
+ mutex = this;
+ }
+ SynchronizedCollection(Collection c, Object mutex) {
+ this.c = c;
+ this.mutex = mutex;
+ }
+
+ public int size() {
+ synchronized (mutex) {return c.size();}
+ }
+ public boolean isEmpty() {
+ synchronized (mutex) {return c.isEmpty();}
+ }
+ public boolean contains(Object o) {
+ synchronized (mutex) {return c.contains(o);}
+ }
+ public Object[] toArray() {
+ synchronized (mutex) {return c.toArray();}
+ }
+ public T[] toArray(T[] a) {
+ synchronized (mutex) {return c.toArray(a);}
+ }
+
+ public Iterator iterator() {
+ return c.iterator(); // Must be manually synched by user!
+ }
+
+ public boolean add(E e) {
+ synchronized (mutex) {return c.add(e);}
+ }
+ public boolean remove(Object o) {
+ synchronized (mutex) {return c.remove(o);}
+ }
+
+ public boolean containsAll(Collection coll) {
+ synchronized (mutex) {return c.containsAll(coll);}
+ }
+ public boolean addAll(Collection coll) {
+ synchronized (mutex) {return c.addAll(coll);}
+ }
+ public boolean removeAll(Collection coll) {
+ synchronized (mutex) {return c.removeAll(coll);}
+ }
+ public boolean retainAll(Collection coll) {
+ synchronized (mutex) {return c.retainAll(coll);}
+ }
+ public void clear() {
+ synchronized (mutex) {c.clear();}
+ }
+ public String toString() {
+ synchronized (mutex) {return c.toString();}
+ }
+ }
+
+ /**
+ * Returns a synchronized (thread-safe) set backed by the specified
+ * set. In order to guarantee serial access, it is critical that
+ * all access to the backing set is accomplished
+ * through the returned set.
+ *
+ * It is imperative that the user manually synchronize on the returned
+ * set when iterating over it:
+ *
+ * Set s = Collections.synchronizedSet(new HashSet());
+ * ...
+ * synchronized (s) {
+ * Iterator i = s.iterator(); // Must be in the synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * Failure to follow this advice may result in non-deterministic behavior.
+ *
+ * The returned set will be serializable if the specified set is
+ * serializable.
+ *
+ * @param s the set to be "wrapped" in a synchronized set.
+ * @return a synchronized view of the specified set.
+ */
+ public static Set synchronizedSet(Set s) {
+ return new SynchronizedSet<>(s);
+ }
+
+ static Set synchronizedSet(Set s, Object mutex) {
+ return new SynchronizedSet<>(s, mutex);
+ }
+
+ /**
+ * @serial include
+ */
+ static class SynchronizedSet
+ extends SynchronizedCollection
+ implements Set {
+ private static final long serialVersionUID = 487447009682186044L;
+
+ SynchronizedSet(Set s) {
+ super(s);
+ }
+ SynchronizedSet(Set s, Object mutex) {
+ super(s, mutex);
+ }
+
+ public boolean equals(Object o) {
+ synchronized (mutex) {return c.equals(o);}
+ }
+ public int hashCode() {
+ synchronized (mutex) {return c.hashCode();}
+ }
+ }
+
+ /**
+ * Returns a synchronized (thread-safe) sorted set backed by the specified
+ * sorted set. In order to guarantee serial access, it is critical that
+ * all access to the backing sorted set is accomplished
+ * through the returned sorted set (or its views).
+ *
+ * It is imperative that the user manually synchronize on the returned
+ * sorted set when iterating over it or any of its subSet,
+ * headSet, or tailSet views.
+ *
+ * SortedSet s = Collections.synchronizedSortedSet(new TreeSet());
+ * ...
+ * synchronized (s) {
+ * Iterator i = s.iterator(); // Must be in the synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * or:
+ *
+ * SortedSet s = Collections.synchronizedSortedSet(new TreeSet());
+ * SortedSet s2 = s.headSet(foo);
+ * ...
+ * synchronized (s) { // Note: s, not s2!!!
+ * Iterator i = s2.iterator(); // Must be in the synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * Failure to follow this advice may result in non-deterministic behavior.
+ *
+ * The returned sorted set will be serializable if the specified
+ * sorted set is serializable.
+ *
+ * @param s the sorted set to be "wrapped" in a synchronized sorted set.
+ * @return a synchronized view of the specified sorted set.
+ */
+ public static SortedSet synchronizedSortedSet(SortedSet s) {
+ return new SynchronizedSortedSet<>(s);
+ }
+
+ /**
+ * @serial include
+ */
+ static class SynchronizedSortedSet
+ extends SynchronizedSet
+ implements SortedSet
+ {
+ private static final long serialVersionUID = 8695801310862127406L;
+
+ private final SortedSet ss;
+
+ SynchronizedSortedSet(SortedSet s) {
+ super(s);
+ ss = s;
+ }
+ SynchronizedSortedSet(SortedSet s, Object mutex) {
+ super(s, mutex);
+ ss = s;
+ }
+
+ public Comparator comparator() {
+ synchronized (mutex) {return ss.comparator();}
+ }
+
+ public SortedSet subSet(E fromElement, E toElement) {
+ synchronized (mutex) {
+ return new SynchronizedSortedSet<>(
+ ss.subSet(fromElement, toElement), mutex);
+ }
+ }
+ public SortedSet headSet(E toElement) {
+ synchronized (mutex) {
+ return new SynchronizedSortedSet<>(ss.headSet(toElement), mutex);
+ }
+ }
+ public SortedSet tailSet(E fromElement) {
+ synchronized (mutex) {
+ return new SynchronizedSortedSet<>(ss.tailSet(fromElement),mutex);
+ }
+ }
+
+ public E first() {
+ synchronized (mutex) {return ss.first();}
+ }
+ public E last() {
+ synchronized (mutex) {return ss.last();}
+ }
+ }
+
+ /**
+ * Returns a synchronized (thread-safe) list backed by the specified
+ * list. In order to guarantee serial access, it is critical that
+ * all access to the backing list is accomplished
+ * through the returned list.
+ *
+ * It is imperative that the user manually synchronize on the returned
+ * list when iterating over it:
+ *
+ * List list = Collections.synchronizedList(new ArrayList());
+ * ...
+ * synchronized (list) {
+ * Iterator i = list.iterator(); // Must be in synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * Failure to follow this advice may result in non-deterministic behavior.
+ *
+ * The returned list will be serializable if the specified list is
+ * serializable.
+ *
+ * @param list the list to be "wrapped" in a synchronized list.
+ * @return a synchronized view of the specified list.
+ */
+ public static List synchronizedList(List list) {
+ return (list instanceof RandomAccess ?
+ new SynchronizedRandomAccessList<>(list) :
+ new SynchronizedList<>(list));
+ }
+
+ static List synchronizedList(List list, Object mutex) {
+ return (list instanceof RandomAccess ?
+ new SynchronizedRandomAccessList<>(list, mutex) :
+ new SynchronizedList<>(list, mutex));
+ }
+
+ /**
+ * @serial include
+ */
+ static class SynchronizedList
+ extends SynchronizedCollection
+ implements List {
+ private static final long serialVersionUID = -7754090372962971524L;
+
+ final List list;
+
+ SynchronizedList(List list) {
+ super(list);
+ this.list = list;
+ }
+ SynchronizedList(List list, Object mutex) {
+ super(list, mutex);
+ this.list = list;
+ }
+
+ public boolean equals(Object o) {
+ synchronized (mutex) {return list.equals(o);}
+ }
+ public int hashCode() {
+ synchronized (mutex) {return list.hashCode();}
+ }
+
+ public E get(int index) {
+ synchronized (mutex) {return list.get(index);}
+ }
+ public E set(int index, E element) {
+ synchronized (mutex) {return list.set(index, element);}
+ }
+ public void add(int index, E element) {
+ synchronized (mutex) {list.add(index, element);}
+ }
+ public E remove(int index) {
+ synchronized (mutex) {return list.remove(index);}
+ }
+
+ public int indexOf(Object o) {
+ synchronized (mutex) {return list.indexOf(o);}
+ }
+ public int lastIndexOf(Object o) {
+ synchronized (mutex) {return list.lastIndexOf(o);}
+ }
+
+ public boolean addAll(int index, Collection c) {
+ synchronized (mutex) {return list.addAll(index, c);}
+ }
+
+ public ListIterator listIterator() {
+ return list.listIterator(); // Must be manually synched by user
+ }
+
+ public ListIterator listIterator(int index) {
+ return list.listIterator(index); // Must be manually synched by user
+ }
+
+ public List subList(int fromIndex, int toIndex) {
+ synchronized (mutex) {
+ return new SynchronizedList<>(list.subList(fromIndex, toIndex),
+ mutex);
+ }
+ }
+
+ /**
+ * SynchronizedRandomAccessList instances are serialized as
+ * SynchronizedList instances to allow them to be deserialized
+ * in pre-1.4 JREs (which do not have SynchronizedRandomAccessList).
+ * This method inverts the transformation. As a beneficial
+ * side-effect, it also grafts the RandomAccess marker onto
+ * SynchronizedList instances that were serialized in pre-1.4 JREs.
+ *
+ * Note: Unfortunately, SynchronizedRandomAccessList instances
+ * serialized in 1.4.1 and deserialized in 1.4 will become
+ * SynchronizedList instances, as this method was missing in 1.4.
+ */
+ private Object readResolve() {
+ return (list instanceof RandomAccess
+ ? new SynchronizedRandomAccessList<>(list)
+ : this);
+ }
+ }
+
+ /**
+ * @serial include
+ */
+ static class SynchronizedRandomAccessList
+ extends SynchronizedList
+ implements RandomAccess {
+
+ SynchronizedRandomAccessList(List list) {
+ super(list);
+ }
+
+ SynchronizedRandomAccessList(List list, Object mutex) {
+ super(list, mutex);
+ }
+
+ public List subList(int fromIndex, int toIndex) {
+ synchronized (mutex) {
+ return new SynchronizedRandomAccessList<>(
+ list.subList(fromIndex, toIndex), mutex);
+ }
+ }
+
+ private static final long serialVersionUID = 1530674583602358482L;
+
+ /**
+ * Allows instances to be deserialized in pre-1.4 JREs (which do
+ * not have SynchronizedRandomAccessList). SynchronizedList has
+ * a readResolve method that inverts this transformation upon
+ * deserialization.
+ */
+ private Object writeReplace() {
+ return new SynchronizedList<>(list);
+ }
+ }
+
+ /**
+ * Returns a synchronized (thread-safe) map backed by the specified
+ * map. In order to guarantee serial access, it is critical that
+ * all access to the backing map is accomplished
+ * through the returned map.
+ *
+ * It is imperative that the user manually synchronize on the returned
+ * map when iterating over any of its collection views:
+ *
+ * Map m = Collections.synchronizedMap(new HashMap());
+ * ...
+ * Set s = m.keySet(); // Needn't be in synchronized block
+ * ...
+ * synchronized (m) { // Synchronizing on m, not s!
+ * Iterator i = s.iterator(); // Must be in synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * Failure to follow this advice may result in non-deterministic behavior.
+ *
+ * The returned map will be serializable if the specified map is
+ * serializable.
+ *
+ * @param m the map to be "wrapped" in a synchronized map.
+ * @return a synchronized view of the specified map.
+ */
+ public static Map synchronizedMap(Map m) {
+ return new SynchronizedMap<>(m);
+ }
+
+ /**
+ * @serial include
+ */
+ private static class SynchronizedMap
+ implements Map, Serializable {
+ private static final long serialVersionUID = 1978198479659022715L;
+
+ private final Map m; // Backing Map
+ final Object mutex; // Object on which to synchronize
+
+ SynchronizedMap(Map m) {
+ if (m==null)
+ throw new NullPointerException();
+ this.m = m;
+ mutex = this;
+ }
+
+ SynchronizedMap(Map m, Object mutex) {
+ this.m = m;
+ this.mutex = mutex;
+ }
+
+ public int size() {
+ synchronized (mutex) {return m.size();}
+ }
+ public boolean isEmpty() {
+ synchronized (mutex) {return m.isEmpty();}
+ }
+ public boolean containsKey(Object key) {
+ synchronized (mutex) {return m.containsKey(key);}
+ }
+ public boolean containsValue(Object value) {
+ synchronized (mutex) {return m.containsValue(value);}
+ }
+ public V get(Object key) {
+ synchronized (mutex) {return m.get(key);}
+ }
+
+ public V put(K key, V value) {
+ synchronized (mutex) {return m.put(key, value);}
+ }
+ public V remove(Object key) {
+ synchronized (mutex) {return m.remove(key);}
+ }
+ public void putAll(Map map) {
+ synchronized (mutex) {m.putAll(map);}
+ }
+ public void clear() {
+ synchronized (mutex) {m.clear();}
+ }
+
+ private transient Set keySet = null;
+ private transient Set> entrySet = null;
+ private transient Collection values = null;
+
+ public Set keySet() {
+ synchronized (mutex) {
+ if (keySet==null)
+ keySet = new SynchronizedSet<>(m.keySet(), mutex);
+ return keySet;
+ }
+ }
+
+ public Set> entrySet() {
+ synchronized (mutex) {
+ if (entrySet==null)
+ entrySet = new SynchronizedSet<>(m.entrySet(), mutex);
+ return entrySet;
+ }
+ }
+
+ public Collection values() {
+ synchronized (mutex) {
+ if (values==null)
+ values = new SynchronizedCollection<>(m.values(), mutex);
+ return values;
+ }
+ }
+
+ public boolean equals(Object o) {
+ synchronized (mutex) {return m.equals(o);}
+ }
+ public int hashCode() {
+ synchronized (mutex) {return m.hashCode();}
+ }
+ public String toString() {
+ synchronized (mutex) {return m.toString();}
+ }
+ }
+
+ /**
+ * Returns a synchronized (thread-safe) sorted map backed by the specified
+ * sorted map. In order to guarantee serial access, it is critical that
+ * all access to the backing sorted map is accomplished
+ * through the returned sorted map (or its views).
+ *
+ * It is imperative that the user manually synchronize on the returned
+ * sorted map when iterating over any of its collection views, or the
+ * collections views of any of its subMap, headMap or
+ * tailMap views.
+ *
+ * SortedMap m = Collections.synchronizedSortedMap(new TreeMap());
+ * ...
+ * Set s = m.keySet(); // Needn't be in synchronized block
+ * ...
+ * synchronized (m) { // Synchronizing on m, not s!
+ * Iterator i = s.iterator(); // Must be in synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * or:
+ *
+ * SortedMap m = Collections.synchronizedSortedMap(new TreeMap());
+ * SortedMap m2 = m.subMap(foo, bar);
+ * ...
+ * Set s2 = m2.keySet(); // Needn't be in synchronized block
+ * ...
+ * synchronized (m) { // Synchronizing on m, not m2 or s2!
+ * Iterator i = s.iterator(); // Must be in synchronized block
+ * while (i.hasNext())
+ * foo(i.next());
+ * }
+ *
+ * Failure to follow this advice may result in non-deterministic behavior.
+ *
+ * The returned sorted map will be serializable if the specified
+ * sorted map is serializable.
+ *
+ * @param m the sorted map to be "wrapped" in a synchronized sorted map.
+ * @return a synchronized view of the specified sorted map.
+ */
+ public static SortedMap synchronizedSortedMap(SortedMap m) {
+ return new SynchronizedSortedMap<>(m);
+ }
+
+
+ /**
+ * @serial include
+ */
+ static class SynchronizedSortedMap
+ extends SynchronizedMap
+ implements SortedMap
+ {
+ private static final long serialVersionUID = -8798146769416483793L;
+
+ private final SortedMap sm;
+
+ SynchronizedSortedMap(SortedMap m) {
+ super(m);
+ sm = m;
+ }
+ SynchronizedSortedMap(SortedMap m, Object mutex) {
+ super(m, mutex);
+ sm = m;
+ }
+
+ public Comparator comparator() {
+ synchronized (mutex) {return sm.comparator();}
+ }
+
+ public SortedMap subMap(K fromKey, K toKey) {
+ synchronized (mutex) {
+ return new SynchronizedSortedMap<>(
+ sm.subMap(fromKey, toKey), mutex);
+ }
+ }
+ public SortedMap headMap(K toKey) {
+ synchronized (mutex) {
+ return new SynchronizedSortedMap<>(sm.headMap(toKey), mutex);
+ }
+ }
+ public SortedMap tailMap(K fromKey) {
+ synchronized (mutex) {
+ return new SynchronizedSortedMap<>(sm.tailMap(fromKey),mutex);
+ }
+ }
+
+ public K firstKey() {
+ synchronized (mutex) {return sm.firstKey();}
+ }
+ public K lastKey() {
+ synchronized (mutex) {return sm.lastKey();}
+ }
+ }
+
+ // Dynamically typesafe collection wrappers
+
+ /**
+ * Returns a dynamically typesafe view of the specified collection.
+ * Any attempt to insert an element of the wrong type will result in an
+ * immediate {@link ClassCastException}. Assuming a collection
+ * contains no incorrectly typed elements prior to the time a
+ * dynamically typesafe view is generated, and that all subsequent
+ * access to the collection takes place through the view, it is
+ * guaranteed that the collection cannot contain an incorrectly
+ * typed element.
+ *
+ * The generics mechanism in the language provides compile-time
+ * (static) type checking, but it is possible to defeat this mechanism
+ * with unchecked casts. Usually this is not a problem, as the compiler
+ * issues warnings on all such unchecked operations. There are, however,
+ * times when static type checking alone is not sufficient. For example,
+ * suppose a collection is passed to a third-party library and it is
+ * imperative that the library code not corrupt the collection by
+ * inserting an element of the wrong type.
+ *
+ *
Another use of dynamically typesafe views is debugging. Suppose a
+ * program fails with a {@code ClassCastException}, indicating that an
+ * incorrectly typed element was put into a parameterized collection.
+ * Unfortunately, the exception can occur at any time after the erroneous
+ * element is inserted, so it typically provides little or no information
+ * as to the real source of the problem. If the problem is reproducible,
+ * one can quickly determine its source by temporarily modifying the
+ * program to wrap the collection with a dynamically typesafe view.
+ * For example, this declaration:
+ *
{@code
+ * Collection c = new HashSet();
+ * }
+ * may be replaced temporarily by this one:
+ * {@code
+ * Collection c = Collections.checkedCollection(
+ * new HashSet(), String.class);
+ * }
+ * Running the program again will cause it to fail at the point where
+ * an incorrectly typed element is inserted into the collection, clearly
+ * identifying the source of the problem. Once the problem is fixed, the
+ * modified declaration may be reverted back to the original.
+ *
+ * The returned collection does not pass the hashCode and equals
+ * operations through to the backing collection, but relies on
+ * {@code Object}'s {@code equals} and {@code hashCode} methods. This
+ * is necessary to preserve the contracts of these operations in the case
+ * that the backing collection is a set or a list.
+ *
+ *
The returned collection will be serializable if the specified
+ * collection is serializable.
+ *
+ *
Since {@code null} is considered to be a value of any reference
+ * type, the returned collection permits insertion of null elements
+ * whenever the backing collection does.
+ *
+ * @param c the collection for which a dynamically typesafe view is to be
+ * returned
+ * @param type the type of element that {@code c} is permitted to hold
+ * @return a dynamically typesafe view of the specified collection
+ * @since 1.5
+ */
+ public static Collection checkedCollection(Collection c,
+ Class type) {
+ return new CheckedCollection<>(c, type);
+ }
+
+ @SuppressWarnings("unchecked")
+ static T[] zeroLengthArray(Class type) {
+ return (T[]) Array.newInstance(type, 0);
+ }
+
+ /**
+ * @serial include
+ */
+ static class CheckedCollection implements Collection, Serializable {
+ private static final long serialVersionUID = 1578914078182001775L;
+
+ final Collection c;
+ final Class type;
+
+ void typeCheck(Object o) {
+ if (o != null && !type.isInstance(o))
+ throw new ClassCastException(badElementMsg(o));
+ }
+
+ private String badElementMsg(Object o) {
+ return "Attempt to insert " + o.getClass() +
+ " element into collection with element type " + type;
+ }
+
+ CheckedCollection(Collection c, Class type) {
+ if (c==null || type == null)
+ throw new NullPointerException();
+ this.c = c;
+ this.type = type;
+ }
+
+ public int size() { return c.size(); }
+ public boolean isEmpty() { return c.isEmpty(); }
+ public boolean contains(Object o) { return c.contains(o); }
+ public Object[] toArray() { return c.toArray(); }
+ public T[] toArray(T[] a) { return c.toArray(a); }
+ public String toString() { return c.toString(); }
+ public boolean remove(Object o) { return c.remove(o); }
+ public void clear() { c.clear(); }
+
+ public boolean containsAll(Collection coll) {
+ return c.containsAll(coll);
+ }
+ public boolean removeAll(Collection coll) {
+ return c.removeAll(coll);
+ }
+ public boolean retainAll(Collection coll) {
+ return c.retainAll(coll);
+ }
+
+ public Iterator iterator() {
+ final Iterator it = c.iterator();
+ return new Iterator() {
+ public boolean hasNext() { return it.hasNext(); }
+ public E next() { return it.next(); }
+ public void remove() { it.remove(); }};
+ }
+
+ public boolean add(E e) {
+ typeCheck(e);
+ return c.add(e);
+ }
+
+ private E[] zeroLengthElementArray = null; // Lazily initialized
+
+ private E[] zeroLengthElementArray() {
+ return zeroLengthElementArray != null ? zeroLengthElementArray :
+ (zeroLengthElementArray = zeroLengthArray(type));
+ }
+
+ @SuppressWarnings("unchecked")
+ Collection checkedCopyOf(Collection coll) {
+ Object[] a = null;
+ try {
+ E[] z = zeroLengthElementArray();
+ a = coll.toArray(z);
+ // Defend against coll violating the toArray contract
+ if (a.getClass() != z.getClass())
+ a = Arrays.copyOf(a, a.length, z.getClass());
+ } catch (ArrayStoreException ignore) {
+ // To get better and consistent diagnostics,
+ // we call typeCheck explicitly on each element.
+ // We call clone() to defend against coll retaining a
+ // reference to the returned array and storing a bad
+ // element into it after it has been type checked.
+ a = coll.toArray().clone();
+ for (Object o : a)
+ typeCheck(o);
+ }
+ // A slight abuse of the type system, but safe here.
+ return (Collection) Arrays.asList(a);
+ }
+
+ public boolean addAll(Collection coll) {
+ // Doing things this way insulates us from concurrent changes
+ // in the contents of coll and provides all-or-nothing
+ // semantics (which we wouldn't get if we type-checked each
+ // element as we added it)
+ return c.addAll(checkedCopyOf(coll));
+ }
+ }
+
+ /**
+ * Returns a dynamically typesafe view of the specified set.
+ * Any attempt to insert an element of the wrong type will result in
+ * an immediate {@link ClassCastException}. Assuming a set contains
+ * no incorrectly typed elements prior to the time a dynamically typesafe
+ * view is generated, and that all subsequent access to the set
+ * takes place through the view, it is guaranteed that the
+ * set cannot contain an incorrectly typed element.
+ *
+ * A discussion of the use of dynamically typesafe views may be
+ * found in the documentation for the {@link #checkedCollection
+ * checkedCollection} method.
+ *
+ *
The returned set will be serializable if the specified set is
+ * serializable.
+ *
+ *
Since {@code null} is considered to be a value of any reference
+ * type, the returned set permits insertion of null elements whenever
+ * the backing set does.
+ *
+ * @param s the set for which a dynamically typesafe view is to be
+ * returned
+ * @param type the type of element that {@code s} is permitted to hold
+ * @return a dynamically typesafe view of the specified set
+ * @since 1.5
+ */
+ public static Set checkedSet(Set s, Class type) {
+ return new CheckedSet<>(s, type);
+ }
+
+ /**
+ * @serial include
+ */
+ static class CheckedSet extends CheckedCollection
+ implements Set, Serializable
+ {
+ private static final long serialVersionUID = 4694047833775013803L;
+
+ CheckedSet(Set s, Class elementType) { super(s, elementType); }
+
+ public boolean equals(Object o) { return o == this || c.equals(o); }
+ public int hashCode() { return c.hashCode(); }
+ }
+
+ /**
+ * Returns a dynamically typesafe view of the specified sorted set.
+ * Any attempt to insert an element of the wrong type will result in an
+ * immediate {@link ClassCastException}. Assuming a sorted set
+ * contains no incorrectly typed elements prior to the time a
+ * dynamically typesafe view is generated, and that all subsequent
+ * access to the sorted set takes place through the view, it is
+ * guaranteed that the sorted set cannot contain an incorrectly
+ * typed element.
+ *
+ * A discussion of the use of dynamically typesafe views may be
+ * found in the documentation for the {@link #checkedCollection
+ * checkedCollection} method.
+ *
+ *
The returned sorted set will be serializable if the specified sorted
+ * set is serializable.
+ *
+ *
Since {@code null} is considered to be a value of any reference
+ * type, the returned sorted set permits insertion of null elements
+ * whenever the backing sorted set does.
+ *
+ * @param s the sorted set for which a dynamically typesafe view is to be
+ * returned
+ * @param type the type of element that {@code s} is permitted to hold
+ * @return a dynamically typesafe view of the specified sorted set
+ * @since 1.5
+ */
+ public static SortedSet checkedSortedSet(SortedSet s,
+ Class type) {
+ return new CheckedSortedSet<>(s, type);
+ }
+
+ /**
+ * @serial include
+ */
+ static class CheckedSortedSet extends CheckedSet
+ implements SortedSet, Serializable
+ {
+ private static final long serialVersionUID = 1599911165492914959L;
+ private final SortedSet