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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/licenses/publicdomain |
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*/ |
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|
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package java.util.concurrent; |
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import java.util.concurrent.*; // for javadoc (till 6280605 is fixed) |
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import java.util.*; |
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|
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/** |
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* A {@link Deque} that additionally supports blocking operations that wait |
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* for the deque to become non-empty when retrieving an element, and wait for |
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* space to become available in the deque when storing an element. |
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* |
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* <p><tt>BlockingDeque</tt> methods come in four forms, with different ways |
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* of handling operations that cannot be satisfied immediately, but may be |
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* satisfied at some point in the future: |
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* one throws an exception, the second returns a special value (either |
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* <tt>null</tt> or <tt>false</tt>, depending on the operation), the third |
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* blocks the current thread indefinitely until the operation can succeed, |
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* and the fourth blocks for only a given maximum time limit before giving |
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* up. These methods are summarized in the following table: |
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* |
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* <p> |
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* <table BORDER CELLPADDING=3 CELLSPACING=1> |
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* <tr> |
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* <td ALIGN=CENTER COLSPAN = 5> <b>First Element (Head)</b></td> |
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* </tr> |
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* <tr> |
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* <td></td> |
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* <td ALIGN=CENTER><em>Throws exception</em></td> |
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* <td ALIGN=CENTER><em>Special value</em></td> |
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* <td ALIGN=CENTER><em>Blocks</em></td> |
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* <td ALIGN=CENTER><em>Times out</em></td> |
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* </tr> |
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* <tr> |
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* <td><b>Insert</b></td> |
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* <td>{@link #addFirst addFirst(e)}</td> |
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* <td>{@link #offerFirst(Object) offerFirst(e)}</td> |
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* <td>{@link #putFirst putFirst(e)}</td> |
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* <td>{@link #offerFirst(Object, long, TimeUnit) offerFirst(e, time, unit)}</td> |
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* </tr> |
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* <tr> |
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* <td><b>Remove</b></td> |
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* <td>{@link #removeFirst removeFirst()}</td> |
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* <td>{@link #pollFirst pollFirst()}</td> |
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* <td>{@link #takeFirst takeFirst()}</td> |
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* <td>{@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}</td> |
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* </tr> |
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* <tr> |
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* <td><b>Examine</b></td> |
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* <td>{@link #getFirst getFirst()}</td> |
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* <td>{@link #peekFirst peekFirst()}</td> |
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* <td><em>not applicable</em></td> |
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* <td><em>not applicable</em></td> |
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* </tr> |
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* <tr> |
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* <td ALIGN=CENTER COLSPAN = 5> <b>Last Element (Tail)</b></td> |
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* </tr> |
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* <tr> |
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* <td></td> |
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* <td ALIGN=CENTER><em>Throws exception</em></td> |
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* <td ALIGN=CENTER><em>Special value</em></td> |
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* <td ALIGN=CENTER><em>Blocks</em></td> |
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* <td ALIGN=CENTER><em>Times out</em></td> |
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* </tr> |
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* <tr> |
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* <td><b>Insert</b></td> |
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* <td>{@link #addLast addLast(e)}</td> |
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* <td>{@link #offerLast(Object) offerLast(e)}</td> |
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* <td>{@link #putLast putLast(e)}</td> |
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* <td>{@link #offerLast(Object, long, TimeUnit) offerLast(e, time, unit)}</td> |
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* </tr> |
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* <tr> |
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* <td><b>Remove</b></td> |
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* <td>{@link #removeLast() removeLast()}</td> |
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* <td>{@link #pollLast() pollLast()}</td> |
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* <td>{@link #takeLast takeLast()}</td> |
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* <td>{@link #pollLast(long, TimeUnit) pollLast(time, unit)}</td> |
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* </tr> |
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* <tr> |
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* <td><b>Examine</b></td> |
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* <td>{@link #getLast getLast()}</td> |
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* <td>{@link #peekLast peekLast()}</td> |
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* <td><em>not applicable</em></td> |
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* <td><em>not applicable</em></td> |
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* </tr> |
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* </table> |
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* |
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* <p>Like any {@link BlockingQueue}, a <tt>BlockingDeque</tt> is thread safe, |
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* does not permit null elements, and may (or may not) be |
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* capacity-constrained. |
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* |
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* <p>A <tt>BlockingDeque</tt> implementation may be used directly as a FIFO |
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* <tt>BlockingQueue</tt>. The methods inherited from the |
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* <tt>BlockingQueue</tt> interface are precisely equivalent to |
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* <tt>BlockingDeque</tt> methods as indicated in the following table: |
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* |
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* <p> |
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* <table BORDER CELLPADDING=3 CELLSPACING=1> |
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* <tr> |
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* <td ALIGN=CENTER> <b><tt>BlockingQueue</tt> Method</b></td> |
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* <td ALIGN=CENTER> <b>Equivalent <tt>BlockingDeque</tt> Method</b></td> |
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* </tr> |
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* <tr> |
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* <td ALIGN=CENTER COLSPAN = 2> <b>Insert</b></td> |
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* </tr> |
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* <tr> |
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* <td>{@link #add(Object) add(e)}</td> |
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* <td>{@link #addLast(Object) addLast(e)}</td> |
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* </tr> |
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* <tr> |
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* <td>{@link #offer(Object) offer(e)}</td> |
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* <td>{@link #offerLast(Object) offerLast(e)}</td> |
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* </tr> |
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* <tr> |
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* <td>{@link #put(Object) put(e)}</td> |
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* <td>{@link #putLast(Object) putLast(e)}</td> |
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* </tr> |
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* <tr> |
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* <td>{@link #offer(Object, long, TimeUnit) offer(e, time, unit)}</td> |
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* <td>{@link #offerLast(Object, long, TimeUnit) offerLast(e, time, unit)}</td> |
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* </tr> |
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* <tr> |
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* <td ALIGN=CENTER COLSPAN = 2> <b>Remove</b></td> |
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* </tr> |
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* <tr> |
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* <td>{@link #remove() remove()}</td> |
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* <td>{@link #removeFirst() removeFirst()}</td> |
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* </tr> |
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* <tr> |
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* <td>{@link #poll() poll()}</td> |
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* <td>{@link #pollFirst() pollFirst()}</td> |
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* </tr> |
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* <tr> |
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* <td>{@link #take() take()}</td> |
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* <td>{@link #takeFirst() takeFirst()}</td> |
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* </tr> |
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* <tr> |
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* <td>{@link #poll(long, TimeUnit) poll(time, unit)}</td> |
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* <td>{@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}</td> |
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* </tr> |
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* <tr> |
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* <td ALIGN=CENTER COLSPAN = 2> <b>Examine</b></td> |
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* </tr> |
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* <tr> |
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* <td>{@link #element() element()}</td> |
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* <td>{@link #getFirst() getFirst()}</td> |
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* </tr> |
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* <tr> |
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* <td>{@link #peek() peek()}</td> |
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* <td>{@link #peekFirst() peekFirst()}</td> |
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* </tr> |
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* </table> |
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* |
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* <p>Memory consistency effects: As with other concurrent |
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* collections, actions in a thread prior to placing an object into a |
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* {@code BlockingDeque} |
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* <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a> |
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* actions subsequent to the access or removal of that element from |
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* the {@code BlockingDeque} in another thread. |
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* |
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* <p>This interface is a member of the |
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* <a href="{@docRoot}/../guide/collections/index.html"> |
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* Java Collections Framework</a>. |
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* |
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* @since 1.6 |
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* @author Doug Lea |
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* @param <E> the type of elements held in this collection |
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*/ |
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public interface BlockingDeque<E> extends BlockingQueue<E>, Deque<E> { |
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/* |
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* We have "diamond" multiple interface inheritance here, and that |
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* introduces ambiguities. Methods might end up with different |
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* specs depending on the branch chosen by javadoc. Thus a lot of |
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* methods specs here are copied from superinterfaces. |
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*/ |
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|
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/** |
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* Inserts the specified element at the front of this deque if it is |
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* possible to do so immediately without violating capacity restrictions, |
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* throwing an <tt>IllegalStateException</tt> if no space is currently |
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* available. When using a capacity-restricted deque, it is generally |
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* preferable to use {@link #offerFirst(Object) offerFirst}. |
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* |
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* @param e the element to add |
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* @throws IllegalStateException {@inheritDoc} |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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void addFirst(E e); |
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|
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/** |
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* Inserts the specified element at the end of this deque if it is |
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* possible to do so immediately without violating capacity restrictions, |
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* throwing an <tt>IllegalStateException</tt> if no space is currently |
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* available. When using a capacity-restricted deque, it is generally |
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* preferable to use {@link #offerLast(Object) offerLast}. |
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* |
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* @param e the element to add |
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* @throws IllegalStateException {@inheritDoc} |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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void addLast(E e); |
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|
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/** |
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* Inserts the specified element at the front of this deque if it is |
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* possible to do so immediately without violating capacity restrictions, |
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* returning <tt>true</tt> upon success and <tt>false</tt> if no space is |
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* currently available. |
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* When using a capacity-restricted deque, this method is generally |
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* preferable to the {@link #addFirst(Object) addFirst} method, which can |
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* fail to insert an element only by throwing an exception. |
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* |
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* @param e the element to add |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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boolean offerFirst(E e); |
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|
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/** |
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* Inserts the specified element at the end of this deque if it is |
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* possible to do so immediately without violating capacity restrictions, |
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* returning <tt>true</tt> upon success and <tt>false</tt> if no space is |
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* currently available. |
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* When using a capacity-restricted deque, this method is generally |
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* preferable to the {@link #addLast(Object) addLast} method, which can |
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* fail to insert an element only by throwing an exception. |
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* |
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* @param e the element to add |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException {@inheritDoc} |
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*/ |
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boolean offerLast(E e); |
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|
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/** |
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* Inserts the specified element at the front of this deque, |
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* waiting if necessary for space to become available. |
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* |
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* @param e the element to add |
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* @throws InterruptedException if interrupted while waiting |
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* @throws ClassCastException if the class of the specified element |
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* prevents it from being added to this deque |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException if some property of the specified |
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* element prevents it from being added to this deque |
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*/ |
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void putFirst(E e) throws InterruptedException; |
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|
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/** |
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* Inserts the specified element at the end of this deque, |
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* waiting if necessary for space to become available. |
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* |
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* @param e the element to add |
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* @throws InterruptedException if interrupted while waiting |
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* @throws ClassCastException if the class of the specified element |
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* prevents it from being added to this deque |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException if some property of the specified |
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* element prevents it from being added to this deque |
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*/ |
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void putLast(E e) throws InterruptedException; |
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|
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/** |
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* Inserts the specified element at the front of this deque, |
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* waiting up to the specified wait time if necessary for space to |
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* become available. |
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* |
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* @param e the element to add |
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* @param timeout how long to wait before giving up, in units of |
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* <tt>unit</tt> |
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* @param unit a <tt>TimeUnit</tt> determining how to interpret the |
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* <tt>timeout</tt> parameter |
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* @return <tt>true</tt> if successful, or <tt>false</tt> if |
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* the specified waiting time elapses before space is available |
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* @throws InterruptedException if interrupted while waiting |
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* @throws ClassCastException if the class of the specified element |
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* prevents it from being added to this deque |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException if some property of the specified |
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* element prevents it from being added to this deque |
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*/ |
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boolean offerFirst(E e, long timeout, TimeUnit unit) |
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throws InterruptedException; |
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|
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/** |
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* Inserts the specified element at the end of this deque, |
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* waiting up to the specified wait time if necessary for space to |
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* become available. |
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* |
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* @param e the element to add |
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* @param timeout how long to wait before giving up, in units of |
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* <tt>unit</tt> |
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* @param unit a <tt>TimeUnit</tt> determining how to interpret the |
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* <tt>timeout</tt> parameter |
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* @return <tt>true</tt> if successful, or <tt>false</tt> if |
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* the specified waiting time elapses before space is available |
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* @throws InterruptedException if interrupted while waiting |
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* @throws ClassCastException if the class of the specified element |
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* prevents it from being added to this deque |
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* @throws NullPointerException if the specified element is null |
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* @throws IllegalArgumentException if some property of the specified |
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* element prevents it from being added to this deque |
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*/ |
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boolean offerLast(E e, long timeout, TimeUnit unit) |
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throws InterruptedException; |
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|
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/** |
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* Retrieves and removes the first element of this deque, waiting |
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* if necessary until an element becomes available. |
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* |
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* @return the head of this deque |
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* @throws InterruptedException if interrupted while waiting |
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*/ |
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E takeFirst() throws InterruptedException; |
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|
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/** |
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* Retrieves and removes the last element of this deque, waiting |
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* if necessary until an element becomes available. |
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* |
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* @return the tail of this deque |
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* @throws InterruptedException if interrupted while waiting |
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*/ |
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E takeLast() throws InterruptedException; |
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|
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/** |
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* Retrieves and removes the first element of this deque, waiting |
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* up to the specified wait time if necessary for an element to |
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* become available. |
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* |
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* @param timeout how long to wait before giving up, in units of |
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* <tt>unit</tt> |
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* @param unit a <tt>TimeUnit</tt> determining how to interpret the |
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* <tt>timeout</tt> parameter |
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* @return the head of this deque, or <tt>null</tt> if the specified |
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* waiting time elapses before an element is available |
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* @throws InterruptedException if interrupted while waiting |
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*/ |
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E pollFirst(long timeout, TimeUnit unit) |
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throws InterruptedException; |
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|
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/** |
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* Retrieves and removes the last element of this deque, waiting |
| 350 |
* up to the specified wait time if necessary for an element to |
| 351 |
* become available. |
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* |
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* @param timeout how long to wait before giving up, in units of |
| 354 |
* <tt>unit</tt> |
| 355 |
* @param unit a <tt>TimeUnit</tt> determining how to interpret the |
| 356 |
* <tt>timeout</tt> parameter |
| 357 |
* @return the tail of this deque, or <tt>null</tt> if the specified |
| 358 |
* waiting time elapses before an element is available |
| 359 |
* @throws InterruptedException if interrupted while waiting |
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*/ |
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E pollLast(long timeout, TimeUnit unit) |
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throws InterruptedException; |
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|
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/** |
| 365 |
* Removes the first occurrence of the specified element from this deque. |
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* If the deque does not contain the element, it is unchanged. |
| 367 |
* More formally, removes the first element <tt>e</tt> such that |
| 368 |
* <tt>o.equals(e)</tt> (if such an element exists). |
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* Returns <tt>true</tt> if this deque contained the specified element |
| 370 |
* (or equivalently, if this deque changed as a result of the call). |
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* |
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* @param o element to be removed from this deque, if present |
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* @return <tt>true</tt> if an element was removed as a result of this call |
| 374 |
* @throws ClassCastException if the class of the specified element |
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* is incompatible with this deque (optional) |
| 376 |
* @throws NullPointerException if the specified element is null (optional) |
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*/ |
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boolean removeFirstOccurrence(Object o); |
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|
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/** |
| 381 |
* Removes the last occurrence of the specified element from this deque. |
| 382 |
* If the deque does not contain the element, it is unchanged. |
| 383 |
* More formally, removes the last element <tt>e</tt> such that |
| 384 |
* <tt>o.equals(e)</tt> (if such an element exists). |
| 385 |
* Returns <tt>true</tt> if this deque contained the specified element |
| 386 |
* (or equivalently, if this deque changed as a result of the call). |
| 387 |
* |
| 388 |
* @param o element to be removed from this deque, if present |
| 389 |
* @return <tt>true</tt> if an element was removed as a result of this call |
| 390 |
* @throws ClassCastException if the class of the specified element |
| 391 |
* is incompatible with this deque (optional) |
| 392 |
* @throws NullPointerException if the specified element is null (optional) |
| 393 |
*/ |
| 394 |
boolean removeLastOccurrence(Object o); |
| 395 |
|
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// *** BlockingQueue methods *** |
| 397 |
|
| 398 |
/** |
| 399 |
* Inserts the specified element into the queue represented by this deque |
| 400 |
* (in other words, at the tail of this deque) if it is possible to do so |
| 401 |
* immediately without violating capacity restrictions, returning |
| 402 |
* <tt>true</tt> upon success and throwing an |
| 403 |
* <tt>IllegalStateException</tt> if no space is currently available. |
| 404 |
* When using a capacity-restricted deque, it is generally preferable to |
| 405 |
* use {@link #offer(Object) offer}. |
| 406 |
* |
| 407 |
* <p>This method is equivalent to {@link #addLast(Object) addLast}. |
| 408 |
* |
| 409 |
* @param e the element to add |
| 410 |
* @throws IllegalStateException {@inheritDoc} |
| 411 |
* @throws ClassCastException if the class of the specified element |
| 412 |
* prevents it from being added to this deque |
| 413 |
* @throws NullPointerException if the specified element is null |
| 414 |
* @throws IllegalArgumentException if some property of the specified |
| 415 |
* element prevents it from being added to this deque |
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*/ |
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boolean add(E e); |
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|
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/** |
| 420 |
* Inserts the specified element into the queue represented by this deque |
| 421 |
* (in other words, at the tail of this deque) if it is possible to do so |
| 422 |
* immediately without violating capacity restrictions, returning |
| 423 |
* <tt>true</tt> upon success and <tt>false</tt> if no space is currently |
| 424 |
* available. When using a capacity-restricted deque, this method is |
| 425 |
* generally preferable to the {@link #add} method, which can fail to |
| 426 |
* insert an element only by throwing an exception. |
| 427 |
* |
| 428 |
* <p>This method is equivalent to {@link #offerLast(Object) offerLast}. |
| 429 |
* |
| 430 |
* @param e the element to add |
| 431 |
* @throws ClassCastException if the class of the specified element |
| 432 |
* prevents it from being added to this deque |
| 433 |
* @throws NullPointerException if the specified element is null |
| 434 |
* @throws IllegalArgumentException if some property of the specified |
| 435 |
* element prevents it from being added to this deque |
| 436 |
*/ |
| 437 |
boolean offer(E e); |
| 438 |
|
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/** |
| 440 |
* Inserts the specified element into the queue represented by this deque |
| 441 |
* (in other words, at the tail of this deque), waiting if necessary for |
| 442 |
* space to become available. |
| 443 |
* |
| 444 |
* <p>This method is equivalent to {@link #putLast(Object) putLast}. |
| 445 |
* |
| 446 |
* @param e the element to add |
| 447 |
* @throws InterruptedException {@inheritDoc} |
| 448 |
* @throws ClassCastException if the class of the specified element |
| 449 |
* prevents it from being added to this deque |
| 450 |
* @throws NullPointerException if the specified element is null |
| 451 |
* @throws IllegalArgumentException if some property of the specified |
| 452 |
* element prevents it from being added to this deque |
| 453 |
*/ |
| 454 |
void put(E e) throws InterruptedException; |
| 455 |
|
| 456 |
/** |
| 457 |
* Inserts the specified element into the queue represented by this deque |
| 458 |
* (in other words, at the tail of this deque), waiting up to the |
| 459 |
* specified wait time if necessary for space to become available. |
| 460 |
* |
| 461 |
* <p>This method is equivalent to |
| 462 |
* {@link #offerLast(Object,long,TimeUnit) offerLast}. |
| 463 |
* |
| 464 |
* @param e the element to add |
| 465 |
* @return <tt>true</tt> if the element was added to this deque, else |
| 466 |
* <tt>false</tt> |
| 467 |
* @throws InterruptedException {@inheritDoc} |
| 468 |
* @throws ClassCastException if the class of the specified element |
| 469 |
* prevents it from being added to this deque |
| 470 |
* @throws NullPointerException if the specified element is null |
| 471 |
* @throws IllegalArgumentException if some property of the specified |
| 472 |
* element prevents it from being added to this deque |
| 473 |
*/ |
| 474 |
boolean offer(E e, long timeout, TimeUnit unit) |
| 475 |
throws InterruptedException; |
| 476 |
|
| 477 |
/** |
| 478 |
* Retrieves and removes the head of the queue represented by this deque |
| 479 |
* (in other words, the first element of this deque). |
| 480 |
* This method differs from {@link #poll poll} only in that it |
| 481 |
* throws an exception if this deque is empty. |
| 482 |
* |
| 483 |
* <p>This method is equivalent to {@link #removeFirst() removeFirst}. |
| 484 |
* |
| 485 |
* @return the head of the queue represented by this deque |
| 486 |
* @throws NoSuchElementException if this deque is empty |
| 487 |
*/ |
| 488 |
E remove(); |
| 489 |
|
| 490 |
/** |
| 491 |
* Retrieves and removes the head of the queue represented by this deque |
| 492 |
* (in other words, the first element of this deque), or returns |
| 493 |
* <tt>null</tt> if this deque is empty. |
| 494 |
* |
| 495 |
* <p>This method is equivalent to {@link #pollFirst()}. |
| 496 |
* |
| 497 |
* @return the head of this deque, or <tt>null</tt> if this deque is empty |
| 498 |
*/ |
| 499 |
E poll(); |
| 500 |
|
| 501 |
/** |
| 502 |
* Retrieves and removes the head of the queue represented by this deque |
| 503 |
* (in other words, the first element of this deque), waiting if |
| 504 |
* necessary until an element becomes available. |
| 505 |
* |
| 506 |
* <p>This method is equivalent to {@link #takeFirst() takeFirst}. |
| 507 |
* |
| 508 |
* @return the head of this deque |
| 509 |
* @throws InterruptedException if interrupted while waiting |
| 510 |
*/ |
| 511 |
E take() throws InterruptedException; |
| 512 |
|
| 513 |
/** |
| 514 |
* Retrieves and removes the head of the queue represented by this deque |
| 515 |
* (in other words, the first element of this deque), waiting up to the |
| 516 |
* specified wait time if necessary for an element to become available. |
| 517 |
* |
| 518 |
* <p>This method is equivalent to |
| 519 |
* {@link #pollFirst(long,TimeUnit) pollFirst}. |
| 520 |
* |
| 521 |
* @return the head of this deque, or <tt>null</tt> if the |
| 522 |
* specified waiting time elapses before an element is available |
| 523 |
* @throws InterruptedException if interrupted while waiting |
| 524 |
*/ |
| 525 |
E poll(long timeout, TimeUnit unit) |
| 526 |
throws InterruptedException; |
| 527 |
|
| 528 |
/** |
| 529 |
* Retrieves, but does not remove, the head of the queue represented by |
| 530 |
* this deque (in other words, the first element of this deque). |
| 531 |
* This method differs from {@link #peek peek} only in that it throws an |
| 532 |
* exception if this deque is empty. |
| 533 |
* |
| 534 |
* <p>This method is equivalent to {@link #getFirst() getFirst}. |
| 535 |
* |
| 536 |
* @return the head of this deque |
| 537 |
* @throws NoSuchElementException if this deque is empty |
| 538 |
*/ |
| 539 |
E element(); |
| 540 |
|
| 541 |
/** |
| 542 |
* Retrieves, but does not remove, the head of the queue represented by |
| 543 |
* this deque (in other words, the first element of this deque), or |
| 544 |
* returns <tt>null</tt> if this deque is empty. |
| 545 |
* |
| 546 |
* <p>This method is equivalent to {@link #peekFirst() peekFirst}. |
| 547 |
* |
| 548 |
* @return the head of this deque, or <tt>null</tt> if this deque is empty |
| 549 |
*/ |
| 550 |
E peek(); |
| 551 |
|
| 552 |
/** |
| 553 |
* Removes the first occurrence of the specified element from this deque. |
| 554 |
* If the deque does not contain the element, it is unchanged. |
| 555 |
* More formally, removes the first element <tt>e</tt> such that |
| 556 |
* <tt>o.equals(e)</tt> (if such an element exists). |
| 557 |
* Returns <tt>true</tt> if this deque contained the specified element |
| 558 |
* (or equivalently, if this deque changed as a result of the call). |
| 559 |
* |
| 560 |
* <p>This method is equivalent to |
| 561 |
* {@link #removeFirstOccurrence(Object) removeFirstOccurrence}. |
| 562 |
* |
| 563 |
* @param o element to be removed from this deque, if present |
| 564 |
* @return <tt>true</tt> if this deque changed as a result of the call |
| 565 |
* @throws ClassCastException if the class of the specified element |
| 566 |
* is incompatible with this deque (optional) |
| 567 |
* @throws NullPointerException if the specified element is null (optional) |
| 568 |
*/ |
| 569 |
boolean remove(Object o); |
| 570 |
|
| 571 |
/** |
| 572 |
* Returns <tt>true</tt> if this deque contains the specified element. |
| 573 |
* More formally, returns <tt>true</tt> if and only if this deque contains |
| 574 |
* at least one element <tt>e</tt> such that <tt>o.equals(e)</tt>. |
| 575 |
* |
| 576 |
* @param o object to be checked for containment in this deque |
| 577 |
* @return <tt>true</tt> if this deque contains the specified element |
| 578 |
* @throws ClassCastException if the class of the specified element |
| 579 |
* is incompatible with this deque (optional) |
| 580 |
* @throws NullPointerException if the specified element is null (optional) |
| 581 |
*/ |
| 582 |
public boolean contains(Object o); |
| 583 |
|
| 584 |
/** |
| 585 |
* Returns the number of elements in this deque. |
| 586 |
* |
| 587 |
* @return the number of elements in this deque |
| 588 |
*/ |
| 589 |
public int size(); |
| 590 |
|
| 591 |
/** |
| 592 |
* Returns an iterator over the elements in this deque in proper sequence. |
| 593 |
* The elements will be returned in order from first (head) to last (tail). |
| 594 |
* |
| 595 |
* @return an iterator over the elements in this deque in proper sequence |
| 596 |
*/ |
| 597 |
Iterator<E> iterator(); |
| 598 |
|
| 599 |
// *** Stack methods *** |
| 600 |
|
| 601 |
/** |
| 602 |
* Pushes an element onto the stack represented by this deque. In other |
| 603 |
* words, inserts the element at the front of this deque unless it would |
| 604 |
* violate capacity restrictions. |
| 605 |
* |
| 606 |
* <p>This method is equivalent to {@link #addFirst(Object) addFirst}. |
| 607 |
* |
| 608 |
* @throws IllegalStateException {@inheritDoc} |
| 609 |
* @throws ClassCastException {@inheritDoc} |
| 610 |
* @throws NullPointerException if the specified element is null |
| 611 |
* @throws IllegalArgumentException {@inheritDoc} |
| 612 |
*/ |
| 613 |
void push(E e); |
| 614 |
} |
