diff -r ee8a922f4268 -r d382dacfd73f rt/emul/compact/src/main/java/java/util/Deque.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/rt/emul/compact/src/main/java/java/util/Deque.java Tue Feb 26 16:54:16 2013 +0100 @@ -0,0 +1,584 @@ +/* + * 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. + */ + +/* + * This file is available under and governed by the GNU General Public + * License version 2 only, as published by the Free Software Foundation. + * However, the following notice accompanied the original version of this + * file: + * + * Written by Doug Lea and Josh Bloch with assistance from members of + * JCP JSR-166 Expert Group and released to the public domain, as explained + * at http://creativecommons.org/publicdomain/zero/1.0/ + */ + +package java.util; + +/** + * A linear collection that supports element insertion and removal at + * both ends. The name deque is short for "double ended queue" + * and is usually pronounced "deck". Most Deque + * implementations place no fixed limits on the number of elements + * they may contain, but this interface supports capacity-restricted + * deques as well as those with no fixed size limit. + * + *
This interface defines methods to access the elements at both + * ends of the deque. Methods are provided to insert, remove, and + * examine the element. Each of these methods exists in two forms: + * one throws an exception if the operation fails, the other returns a + * special value (either null or false, depending on + * the operation). The latter form of the insert operation is + * designed specifically for use with capacity-restricted + * Deque implementations; in most implementations, insert + * operations cannot fail. + * + *
The twelve methods described above are summarized in the + * following table: + * + *
+ *
+ * | First Element (Head) | + *Last Element (Tail) | + *||
+ * | Throws exception | + *Special value | + *Throws exception | + *Special value | + *
Insert | + *{@link #addFirst addFirst(e)} | + *{@link #offerFirst offerFirst(e)} | + *{@link #addLast addLast(e)} | + *{@link #offerLast offerLast(e)} | + *
Remove | + *{@link #removeFirst removeFirst()} | + *{@link #pollFirst pollFirst()} | + *{@link #removeLast removeLast()} | + *{@link #pollLast pollLast()} | + *
Examine | + *{@link #getFirst getFirst()} | + *{@link #peekFirst peekFirst()} | + *{@link #getLast getLast()} | + *{@link #peekLast peekLast()} | + *
This interface extends the {@link Queue} interface. When a deque is + * used as a queue, FIFO (First-In-First-Out) behavior results. Elements are + * added at the end of the deque and removed from the beginning. The methods + * inherited from the Queue interface are precisely equivalent to + * Deque methods as indicated in the following table: + * + *
+ *
Queue Method | + *Equivalent Deque Method | + *
{@link java.util.Queue#add add(e)} | + *{@link #addLast addLast(e)} | + *
{@link java.util.Queue#offer offer(e)} | + *{@link #offerLast offerLast(e)} | + *
{@link java.util.Queue#remove remove()} | + *{@link #removeFirst removeFirst()} | + *
{@link java.util.Queue#poll poll()} | + *{@link #pollFirst pollFirst()} | + *
{@link java.util.Queue#element element()} | + *{@link #getFirst getFirst()} | + *
{@link java.util.Queue#peek peek()} | + *{@link #peek peekFirst()} | + *
Deques can also be used as LIFO (Last-In-First-Out) stacks. This + * interface should be used in preference to the legacy {@link Stack} class. + * When a deque is used as a stack, elements are pushed and popped from the + * beginning of the deque. Stack methods are precisely equivalent to + * Deque methods as indicated in the table below: + * + *
+ *
Stack Method | + *Equivalent Deque Method | + *
{@link #push push(e)} | + *{@link #addFirst addFirst(e)} | + *
{@link #pop pop()} | + *{@link #removeFirst removeFirst()} | + *
{@link #peek peek()} | + *{@link #peekFirst peekFirst()} | + *
Note that the {@link #peek peek} method works equally well when + * a deque is used as a queue or a stack; in either case, elements are + * drawn from the beginning of the deque. + * + *
This interface provides two methods to remove interior + * elements, {@link #removeFirstOccurrence removeFirstOccurrence} and + * {@link #removeLastOccurrence removeLastOccurrence}. + * + *
Unlike the {@link List} interface, this interface does not + * provide support for indexed access to elements. + * + *
While Deque implementations are not strictly required + * to prohibit the insertion of null elements, they are strongly + * encouraged to do so. Users of any Deque implementations + * that do allow null elements are strongly encouraged not to + * take advantage of the ability to insert nulls. This is so because + * null is used as a special return value by various methods + * to indicated that the deque is empty. + * + *
Deque implementations generally do not define + * element-based versions of the equals and hashCode + * methods, but instead inherit the identity-based versions from class + * Object. + * + *
This interface is a member of the Java Collections
+ * Framework.
+ *
+ * @author Doug Lea
+ * @author Josh Bloch
+ * @since 1.6
+ * @param This method is equivalent to {@link #add}.
+ *
+ * @param e the element to add
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ void addLast(E e);
+
+ /**
+ * Inserts the specified element at the front of this deque unless it would
+ * violate capacity restrictions. When using a capacity-restricted deque,
+ * this method is generally preferable to the {@link #addFirst} method,
+ * which can fail to insert an element only by throwing an exception.
+ *
+ * @param e the element to add
+ * @return true if the element was added to this deque, else
+ * false
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean offerFirst(E e);
+
+ /**
+ * Inserts the specified element at the end of this deque unless it would
+ * violate capacity restrictions. When using a capacity-restricted deque,
+ * this method is generally preferable to the {@link #addLast} method,
+ * which can fail to insert an element only by throwing an exception.
+ *
+ * @param e the element to add
+ * @return true if the element was added to this deque, else
+ * false
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean offerLast(E e);
+
+ /**
+ * Retrieves and removes the first element of this deque. This method
+ * differs from {@link #pollFirst pollFirst} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * @return the head of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E removeFirst();
+
+ /**
+ * Retrieves and removes the last element of this deque. This method
+ * differs from {@link #pollLast pollLast} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * @return the tail of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E removeLast();
+
+ /**
+ * Retrieves and removes the first element of this deque,
+ * or returns null if this deque is empty.
+ *
+ * @return the head of this deque, or null if this deque is empty
+ */
+ E pollFirst();
+
+ /**
+ * Retrieves and removes the last element of this deque,
+ * or returns null if this deque is empty.
+ *
+ * @return the tail of this deque, or null if this deque is empty
+ */
+ E pollLast();
+
+ /**
+ * Retrieves, but does not remove, the first element of this deque.
+ *
+ * This method differs from {@link #peekFirst peekFirst} only in that it
+ * throws an exception if this deque is empty.
+ *
+ * @return the head of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E getFirst();
+
+ /**
+ * Retrieves, but does not remove, the last element of this deque.
+ * This method differs from {@link #peekLast peekLast} only in that it
+ * throws an exception if this deque is empty.
+ *
+ * @return the tail of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E getLast();
+
+ /**
+ * Retrieves, but does not remove, the first element of this deque,
+ * or returns null if this deque is empty.
+ *
+ * @return the head of this deque, or null if this deque is empty
+ */
+ E peekFirst();
+
+ /**
+ * Retrieves, but does not remove, the last element of this deque,
+ * or returns null if this deque is empty.
+ *
+ * @return the tail of this deque, or null if this deque is empty
+ */
+ E peekLast();
+
+ /**
+ * Removes the first occurrence of the specified element from this deque.
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the first element e such that
+ * (o==null ? e==null : o.equals(e))
+ * (if such an element exists).
+ * Returns true if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * @param o element to be removed from this deque, if present
+ * @return true if an element was removed as a result of this call
+ * @throws ClassCastException if the class of the specified element
+ * is incompatible with this deque
+ * (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * (optional)
+ */
+ boolean removeFirstOccurrence(Object o);
+
+ /**
+ * Removes the last occurrence of the specified element from this deque.
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the last element e such that
+ * (o==null ? e==null : o.equals(e))
+ * (if such an element exists).
+ * Returns true if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * @param o element to be removed from this deque, if present
+ * @return true if an element was removed as a result of this call
+ * @throws ClassCastException if the class of the specified element
+ * is incompatible with this deque
+ * (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * (optional)
+ */
+ boolean removeLastOccurrence(Object o);
+
+ // *** Queue methods ***
+
+ /**
+ * Inserts the specified element into the queue represented by this deque
+ * (in other words, at the tail of this deque) if it is possible to do so
+ * immediately without violating capacity restrictions, returning
+ * true upon success and throwing an
+ * IllegalStateException if no space is currently available.
+ * When using a capacity-restricted deque, it is generally preferable to
+ * use {@link #offer(Object) offer}.
+ *
+ * This method is equivalent to {@link #addLast}.
+ *
+ * @param e the element to add
+ * @return true (as specified by {@link Collection#add})
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean add(E e);
+
+ /**
+ * Inserts the specified element into the queue represented by this deque
+ * (in other words, at the tail of this deque) if it is possible to do so
+ * immediately without violating capacity restrictions, returning
+ * true upon success and false if no space is currently
+ * available. When using a capacity-restricted deque, this method is
+ * generally preferable to the {@link #add} method, which can fail to
+ * insert an element only by throwing an exception.
+ *
+ * This method is equivalent to {@link #offerLast}.
+ *
+ * @param e the element to add
+ * @return true if the element was added to this deque, else
+ * false
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean offer(E e);
+
+ /**
+ * Retrieves and removes the head of the queue represented by this deque
+ * (in other words, the first element of this deque).
+ * This method differs from {@link #poll poll} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * This method is equivalent to {@link #removeFirst()}.
+ *
+ * @return the head of the queue represented by this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E remove();
+
+ /**
+ * Retrieves and removes the head of the queue represented by this deque
+ * (in other words, the first element of this deque), or returns
+ * null if this deque is empty.
+ *
+ * This method is equivalent to {@link #pollFirst()}.
+ *
+ * @return the first element of this deque, or null if
+ * this deque is empty
+ */
+ E poll();
+
+ /**
+ * Retrieves, but does not remove, the head of the queue represented by
+ * this deque (in other words, the first element of this deque).
+ * This method differs from {@link #peek peek} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * This method is equivalent to {@link #getFirst()}.
+ *
+ * @return the head of the queue represented by this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E element();
+
+ /**
+ * Retrieves, but does not remove, the head of the queue represented by
+ * this deque (in other words, the first element of this deque), or
+ * returns null if this deque is empty.
+ *
+ * This method is equivalent to {@link #peekFirst()}.
+ *
+ * @return the head of the queue represented by this deque, or
+ * null if this deque is empty
+ */
+ E peek();
+
+
+ // *** Stack methods ***
+
+ /**
+ * Pushes an element onto the stack represented by this deque (in other
+ * words, at the head of this deque) if it is possible to do so
+ * immediately without violating capacity restrictions, returning
+ * true upon success and throwing an
+ * IllegalStateException if no space is currently available.
+ *
+ * This method is equivalent to {@link #addFirst}.
+ *
+ * @param e the element to push
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ void push(E e);
+
+ /**
+ * Pops an element from the stack represented by this deque. In other
+ * words, removes and returns the first element of this deque.
+ *
+ * This method is equivalent to {@link #removeFirst()}.
+ *
+ * @return the element at the front of this deque (which is the top
+ * of the stack represented by this deque)
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E pop();
+
+
+ // *** Collection methods ***
+
+ /**
+ * Removes the first occurrence of the specified element from this deque.
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the first element e such that
+ * (o==null ? e==null : o.equals(e))
+ * (if such an element exists).
+ * Returns true if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * This method is equivalent to {@link #removeFirstOccurrence}.
+ *
+ * @param o element to be removed from this deque, if present
+ * @return true if an element was removed as a result of this call
+ * @throws ClassCastException if the class of the specified element
+ * is incompatible with this deque
+ * (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * (optional)
+ */
+ boolean remove(Object o);
+
+ /**
+ * Returns true if this deque contains the specified element.
+ * More formally, returns true if and only if this deque contains
+ * at least one element e such that
+ * (o==null ? e==null : o.equals(e)).
+ *
+ * @param o element whose presence in this deque is to be tested
+ * @return true if this deque contains the specified element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this deque
+ * (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * (optional)
+ */
+ boolean contains(Object o);
+
+ /**
+ * Returns the number of elements in this deque.
+ *
+ * @return the number of elements in this deque
+ */
+ public int size();
+
+ /**
+ * Returns an iterator over the elements in this deque in proper sequence.
+ * The elements will be returned in order from first (head) to last (tail).
+ *
+ * @return an iterator over the elements in this deque in proper sequence
+ */
+ Iterator