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dl |
1.2 |
/* |
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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. Use, modify, and |
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* redistribute this code in any way without acknowledgement. |
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*/ |
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tim |
1.1 |
package java.util; |
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/** |
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* AbstractQueue provides default implementations of add, remove, and |
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* element based on offer, poll, and peek, respectively but that throw |
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* exceptions instead of indicating failure via false or null returns. |
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* The provided implementations all assume that the base implementation |
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brian |
1.3 |
* does <em>not</em> allow <tt>null</tt> elements. |
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dl |
1.4 |
* @since 1.5 |
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* @author Doug Lea |
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tim |
1.1 |
*/ |
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tim |
1.5 |
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tim |
1.1 |
public abstract class AbstractQueue<E> extends AbstractCollection<E> implements Queue<E> { |
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public boolean add(E x) { |
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if (offer(x)) |
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return true; |
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else |
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throw new IllegalStateException("Queue full"); |
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} |
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tim |
1.8 |
public E remove() { |
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tim |
1.1 |
E x = poll(); |
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if (x != null) |
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return x; |
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else |
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throw new NoSuchElementException(); |
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} |
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tim |
1.8 |
public E element() { |
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tim |
1.1 |
E x = peek(); |
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if (x != null) |
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return x; |
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else |
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throw new NoSuchElementException(); |
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} |
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public void clear() { |
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while (poll() != null) |
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; |
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} |
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tim |
1.7 |
// XXX Remove this redundant declaration, pending response from Neal Gafter. |
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tim |
1.5 |
public abstract Iterator<E> iterator(); |
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tim |
1.1 |
} |
52 |
dholmes |
1.6 |
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