diff -r 5652acd48509 -r 42bc1e89134d emul/compact/src/main/java/java/util/Deque.java --- a/emul/compact/src/main/java/java/util/Deque.java Mon Feb 25 19:00:08 2013 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,584 +0,0 @@ -/* - * 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 exceptionSpecial valueThrows exceptionSpecial 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 the type of elements held in this collection - */ - -public interface Deque extends Queue { - /** - * Inserts the specified element at the front of this deque if it is - * possible to do so immediately without violating capacity restrictions. - * When using a capacity-restricted deque, it is generally preferable to - * use method {@link #offerFirst}. - * - * @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 addFirst(E e); - - /** - * Inserts the specified element at the end of this deque if it is - * possible to do so immediately without violating capacity restrictions. - * When using a capacity-restricted deque, it is generally preferable to - * use method {@link #offerLast}. - * - *

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 iterator(); - - /** - * Returns an iterator over the elements in this deque in reverse - * sequential order. The elements will be returned in order from - * last (tail) to first (head). - * - * @return an iterator over the elements in this deque in reverse - * sequence - */ - Iterator descendingIterator(); - -}