1 |
dl |
1.1 |
/* |
2 |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
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* Expert Group and released to the public domain, as explained at |
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jsr166 |
1.27 |
* http://creativecommons.org/publicdomain/zero/1.0/ |
5 |
dl |
1.1 |
*/ |
6 |
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package java.util.concurrent; |
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jsr166 |
1.21 |
|
9 |
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import java.util.AbstractQueue; |
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import java.util.Collection; |
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dl |
1.36 |
import java.util.Collections; |
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jsr166 |
1.21 |
import java.util.Iterator; |
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import java.util.NoSuchElementException; |
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import java.util.concurrent.locks.Condition; |
15 |
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import java.util.concurrent.locks.ReentrantLock; |
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dl |
1.36 |
import java.util.Spliterator; |
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import java.util.stream.Stream; |
18 |
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import java.util.stream.Streams; |
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import java.util.function.Consumer; |
20 |
dl |
1.1 |
|
21 |
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/** |
22 |
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* An optionally-bounded {@linkplain BlockingDeque blocking deque} based on |
23 |
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* linked nodes. |
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* |
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jsr166 |
1.35 |
* <p>The optional capacity bound constructor argument serves as a |
26 |
dl |
1.1 |
* way to prevent excessive expansion. The capacity, if unspecified, |
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* is equal to {@link Integer#MAX_VALUE}. Linked nodes are |
28 |
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* dynamically created upon each insertion unless this would bring the |
29 |
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* deque above capacity. |
30 |
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* |
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* <p>Most operations run in constant time (ignoring time spent |
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* blocking). Exceptions include {@link #remove(Object) remove}, |
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* {@link #removeFirstOccurrence removeFirstOccurrence}, {@link |
34 |
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* #removeLastOccurrence removeLastOccurrence}, {@link #contains |
35 |
jsr166 |
1.9 |
* contains}, {@link #iterator iterator.remove()}, and the bulk |
36 |
dl |
1.1 |
* operations, all of which run in linear time. |
37 |
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* |
38 |
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* <p>This class and its iterator implement all of the |
39 |
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* <em>optional</em> methods of the {@link Collection} and {@link |
40 |
jsr166 |
1.9 |
* Iterator} interfaces. |
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* |
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* <p>This class is a member of the |
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jsr166 |
1.18 |
* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
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jsr166 |
1.9 |
* Java Collections Framework</a>. |
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dl |
1.1 |
* |
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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 |
49 |
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*/ |
50 |
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public class LinkedBlockingDeque<E> |
51 |
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extends AbstractQueue<E> |
52 |
jsr166 |
1.33 |
implements BlockingDeque<E>, java.io.Serializable { |
53 |
dl |
1.1 |
|
54 |
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/* |
55 |
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* Implemented as a simple doubly-linked list protected by a |
56 |
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* single lock and using conditions to manage blocking. |
57 |
jsr166 |
1.21 |
* |
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* To implement weakly consistent iterators, it appears we need to |
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* keep all Nodes GC-reachable from a predecessor dequeued Node. |
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* That would cause two problems: |
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* - allow a rogue Iterator to cause unbounded memory retention |
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* - cause cross-generational linking of old Nodes to new Nodes if |
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* a Node was tenured while live, which generational GCs have a |
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* hard time dealing with, causing repeated major collections. |
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* However, only non-deleted Nodes need to be reachable from |
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* dequeued Nodes, and reachability does not necessarily have to |
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* be of the kind understood by the GC. We use the trick of |
68 |
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* linking a Node that has just been dequeued to itself. Such a |
69 |
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* self-link implicitly means to jump to "first" (for next links) |
70 |
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* or "last" (for prev links). |
71 |
dl |
1.1 |
*/ |
72 |
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|
73 |
jsr166 |
1.9 |
/* |
74 |
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* We have "diamond" multiple interface/abstract class inheritance |
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* here, and that introduces ambiguities. Often we want the |
76 |
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* BlockingDeque javadoc combined with the AbstractQueue |
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* implementation, so a lot of method specs are duplicated here. |
78 |
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*/ |
79 |
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|
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dl |
1.1 |
private static final long serialVersionUID = -387911632671998426L; |
81 |
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82 |
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/** Doubly-linked list node class */ |
83 |
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static final class Node<E> { |
84 |
jsr166 |
1.21 |
/** |
85 |
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* The item, or null if this node has been removed. |
86 |
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*/ |
87 |
jsr166 |
1.19 |
E item; |
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jsr166 |
1.21 |
|
89 |
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/** |
90 |
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* One of: |
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* - the real predecessor Node |
92 |
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* - this Node, meaning the predecessor is tail |
93 |
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* - null, meaning there is no predecessor |
94 |
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*/ |
95 |
dl |
1.1 |
Node<E> prev; |
96 |
jsr166 |
1.21 |
|
97 |
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/** |
98 |
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* One of: |
99 |
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* - the real successor Node |
100 |
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* - this Node, meaning the successor is head |
101 |
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* - null, meaning there is no successor |
102 |
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*/ |
103 |
dl |
1.1 |
Node<E> next; |
104 |
jsr166 |
1.21 |
|
105 |
dl |
1.23 |
Node(E x) { |
106 |
dl |
1.1 |
item = x; |
107 |
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} |
108 |
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} |
109 |
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110 |
jsr166 |
1.21 |
/** |
111 |
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* Pointer to first node. |
112 |
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* Invariant: (first == null && last == null) || |
113 |
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* (first.prev == null && first.item != null) |
114 |
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*/ |
115 |
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transient Node<E> first; |
116 |
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117 |
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/** |
118 |
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* Pointer to last node. |
119 |
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* Invariant: (first == null && last == null) || |
120 |
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* (last.next == null && last.item != null) |
121 |
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*/ |
122 |
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transient Node<E> last; |
123 |
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124 |
dl |
1.1 |
/** Number of items in the deque */ |
125 |
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private transient int count; |
126 |
jsr166 |
1.21 |
|
127 |
dl |
1.1 |
/** Maximum number of items in the deque */ |
128 |
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private final int capacity; |
129 |
jsr166 |
1.21 |
|
130 |
dl |
1.1 |
/** Main lock guarding all access */ |
131 |
jsr166 |
1.21 |
final ReentrantLock lock = new ReentrantLock(); |
132 |
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133 |
dl |
1.1 |
/** Condition for waiting takes */ |
134 |
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private final Condition notEmpty = lock.newCondition(); |
135 |
jsr166 |
1.21 |
|
136 |
dl |
1.1 |
/** Condition for waiting puts */ |
137 |
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private final Condition notFull = lock.newCondition(); |
138 |
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139 |
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/** |
140 |
jsr166 |
1.21 |
* Creates a {@code LinkedBlockingDeque} with a capacity of |
141 |
dl |
1.1 |
* {@link Integer#MAX_VALUE}. |
142 |
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*/ |
143 |
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public LinkedBlockingDeque() { |
144 |
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this(Integer.MAX_VALUE); |
145 |
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} |
146 |
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147 |
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/** |
148 |
jsr166 |
1.21 |
* Creates a {@code LinkedBlockingDeque} with the given (fixed) capacity. |
149 |
jsr166 |
1.9 |
* |
150 |
dl |
1.1 |
* @param capacity the capacity of this deque |
151 |
jsr166 |
1.21 |
* @throws IllegalArgumentException if {@code capacity} is less than 1 |
152 |
dl |
1.1 |
*/ |
153 |
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public LinkedBlockingDeque(int capacity) { |
154 |
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if (capacity <= 0) throw new IllegalArgumentException(); |
155 |
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this.capacity = capacity; |
156 |
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} |
157 |
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|
158 |
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/** |
159 |
jsr166 |
1.21 |
* Creates a {@code LinkedBlockingDeque} with a capacity of |
160 |
jsr166 |
1.9 |
* {@link Integer#MAX_VALUE}, initially containing the elements of |
161 |
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* the given collection, added in traversal order of the |
162 |
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* collection's iterator. |
163 |
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* |
164 |
dl |
1.1 |
* @param c the collection of elements to initially contain |
165 |
jsr166 |
1.9 |
* @throws NullPointerException if the specified collection or any |
166 |
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* of its elements are null |
167 |
dl |
1.1 |
*/ |
168 |
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public LinkedBlockingDeque(Collection<? extends E> c) { |
169 |
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this(Integer.MAX_VALUE); |
170 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
171 |
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lock.lock(); // Never contended, but necessary for visibility |
172 |
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try { |
173 |
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for (E e : c) { |
174 |
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if (e == null) |
175 |
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throw new NullPointerException(); |
176 |
dl |
1.23 |
if (!linkLast(new Node<E>(e))) |
177 |
jsr166 |
1.21 |
throw new IllegalStateException("Deque full"); |
178 |
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} |
179 |
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} finally { |
180 |
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lock.unlock(); |
181 |
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} |
182 |
dl |
1.1 |
} |
183 |
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184 |
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185 |
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// Basic linking and unlinking operations, called only while holding lock |
186 |
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187 |
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/** |
188 |
dl |
1.23 |
* Links node as first element, or returns false if full. |
189 |
dl |
1.1 |
*/ |
190 |
dl |
1.23 |
private boolean linkFirst(Node<E> node) { |
191 |
jsr166 |
1.21 |
// assert lock.isHeldByCurrentThread(); |
192 |
dl |
1.1 |
if (count >= capacity) |
193 |
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return false; |
194 |
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Node<E> f = first; |
195 |
dl |
1.23 |
node.next = f; |
196 |
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first = node; |
197 |
dl |
1.1 |
if (last == null) |
198 |
dl |
1.23 |
last = node; |
199 |
dl |
1.1 |
else |
200 |
dl |
1.23 |
f.prev = node; |
201 |
jsr166 |
1.21 |
++count; |
202 |
dl |
1.1 |
notEmpty.signal(); |
203 |
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return true; |
204 |
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} |
205 |
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206 |
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/** |
207 |
dl |
1.23 |
* Links node as last element, or returns false if full. |
208 |
dl |
1.1 |
*/ |
209 |
dl |
1.23 |
private boolean linkLast(Node<E> node) { |
210 |
jsr166 |
1.21 |
// assert lock.isHeldByCurrentThread(); |
211 |
dl |
1.1 |
if (count >= capacity) |
212 |
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return false; |
213 |
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Node<E> l = last; |
214 |
dl |
1.23 |
node.prev = l; |
215 |
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last = node; |
216 |
dl |
1.1 |
if (first == null) |
217 |
dl |
1.23 |
first = node; |
218 |
dl |
1.1 |
else |
219 |
dl |
1.23 |
l.next = node; |
220 |
jsr166 |
1.21 |
++count; |
221 |
dl |
1.1 |
notEmpty.signal(); |
222 |
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return true; |
223 |
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} |
224 |
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|
225 |
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/** |
226 |
jsr166 |
1.3 |
* Removes and returns first element, or null if empty. |
227 |
dl |
1.1 |
*/ |
228 |
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private E unlinkFirst() { |
229 |
jsr166 |
1.21 |
// assert lock.isHeldByCurrentThread(); |
230 |
dl |
1.1 |
Node<E> f = first; |
231 |
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if (f == null) |
232 |
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return null; |
233 |
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Node<E> n = f.next; |
234 |
jsr166 |
1.21 |
E item = f.item; |
235 |
|
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f.item = null; |
236 |
|
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f.next = f; // help GC |
237 |
dl |
1.1 |
first = n; |
238 |
jsr166 |
1.3 |
if (n == null) |
239 |
dl |
1.1 |
last = null; |
240 |
jsr166 |
1.3 |
else |
241 |
dl |
1.1 |
n.prev = null; |
242 |
|
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--count; |
243 |
|
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notFull.signal(); |
244 |
jsr166 |
1.21 |
return item; |
245 |
dl |
1.1 |
} |
246 |
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|
247 |
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/** |
248 |
jsr166 |
1.3 |
* Removes and returns last element, or null if empty. |
249 |
dl |
1.1 |
*/ |
250 |
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private E unlinkLast() { |
251 |
jsr166 |
1.21 |
// assert lock.isHeldByCurrentThread(); |
252 |
dl |
1.1 |
Node<E> l = last; |
253 |
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if (l == null) |
254 |
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return null; |
255 |
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Node<E> p = l.prev; |
256 |
jsr166 |
1.21 |
E item = l.item; |
257 |
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l.item = null; |
258 |
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l.prev = l; // help GC |
259 |
dl |
1.1 |
last = p; |
260 |
jsr166 |
1.3 |
if (p == null) |
261 |
dl |
1.1 |
first = null; |
262 |
jsr166 |
1.3 |
else |
263 |
dl |
1.1 |
p.next = null; |
264 |
|
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--count; |
265 |
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notFull.signal(); |
266 |
jsr166 |
1.21 |
return item; |
267 |
dl |
1.1 |
} |
268 |
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|
269 |
|
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/** |
270 |
jsr166 |
1.21 |
* Unlinks x. |
271 |
dl |
1.1 |
*/ |
272 |
jsr166 |
1.21 |
void unlink(Node<E> x) { |
273 |
|
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// assert lock.isHeldByCurrentThread(); |
274 |
dl |
1.1 |
Node<E> p = x.prev; |
275 |
|
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Node<E> n = x.next; |
276 |
|
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if (p == null) { |
277 |
jsr166 |
1.21 |
unlinkFirst(); |
278 |
dl |
1.1 |
} else if (n == null) { |
279 |
jsr166 |
1.21 |
unlinkLast(); |
280 |
dl |
1.1 |
} else { |
281 |
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p.next = n; |
282 |
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n.prev = p; |
283 |
jsr166 |
1.21 |
x.item = null; |
284 |
|
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// Don't mess with x's links. They may still be in use by |
285 |
|
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// an iterator. |
286 |
|
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--count; |
287 |
|
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notFull.signal(); |
288 |
dl |
1.1 |
} |
289 |
|
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} |
290 |
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|
291 |
jsr166 |
1.9 |
// BlockingDeque methods |
292 |
dl |
1.1 |
|
293 |
jsr166 |
1.9 |
/** |
294 |
|
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* @throws IllegalStateException {@inheritDoc} |
295 |
|
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* @throws NullPointerException {@inheritDoc} |
296 |
|
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*/ |
297 |
|
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public void addFirst(E e) { |
298 |
|
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if (!offerFirst(e)) |
299 |
|
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throw new IllegalStateException("Deque full"); |
300 |
|
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} |
301 |
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|
302 |
|
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/** |
303 |
|
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* @throws IllegalStateException {@inheritDoc} |
304 |
|
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* @throws NullPointerException {@inheritDoc} |
305 |
|
|
*/ |
306 |
|
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public void addLast(E e) { |
307 |
|
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if (!offerLast(e)) |
308 |
|
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throw new IllegalStateException("Deque full"); |
309 |
|
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} |
310 |
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|
311 |
|
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/** |
312 |
|
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* @throws NullPointerException {@inheritDoc} |
313 |
|
|
*/ |
314 |
jsr166 |
1.6 |
public boolean offerFirst(E e) { |
315 |
|
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if (e == null) throw new NullPointerException(); |
316 |
dl |
1.23 |
Node<E> node = new Node<E>(e); |
317 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
318 |
dl |
1.1 |
lock.lock(); |
319 |
|
|
try { |
320 |
dl |
1.23 |
return linkFirst(node); |
321 |
dl |
1.1 |
} finally { |
322 |
|
|
lock.unlock(); |
323 |
|
|
} |
324 |
|
|
} |
325 |
|
|
|
326 |
jsr166 |
1.9 |
/** |
327 |
|
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* @throws NullPointerException {@inheritDoc} |
328 |
|
|
*/ |
329 |
jsr166 |
1.6 |
public boolean offerLast(E e) { |
330 |
|
|
if (e == null) throw new NullPointerException(); |
331 |
dl |
1.23 |
Node<E> node = new Node<E>(e); |
332 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
333 |
dl |
1.1 |
lock.lock(); |
334 |
|
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try { |
335 |
dl |
1.23 |
return linkLast(node); |
336 |
dl |
1.1 |
} finally { |
337 |
|
|
lock.unlock(); |
338 |
|
|
} |
339 |
|
|
} |
340 |
|
|
|
341 |
jsr166 |
1.9 |
/** |
342 |
|
|
* @throws NullPointerException {@inheritDoc} |
343 |
|
|
* @throws InterruptedException {@inheritDoc} |
344 |
|
|
*/ |
345 |
|
|
public void putFirst(E e) throws InterruptedException { |
346 |
|
|
if (e == null) throw new NullPointerException(); |
347 |
dl |
1.23 |
Node<E> node = new Node<E>(e); |
348 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
349 |
dl |
1.1 |
lock.lock(); |
350 |
|
|
try { |
351 |
dl |
1.23 |
while (!linkFirst(node)) |
352 |
jsr166 |
1.9 |
notFull.await(); |
353 |
dl |
1.1 |
} finally { |
354 |
|
|
lock.unlock(); |
355 |
|
|
} |
356 |
|
|
} |
357 |
|
|
|
358 |
jsr166 |
1.9 |
/** |
359 |
|
|
* @throws NullPointerException {@inheritDoc} |
360 |
|
|
* @throws InterruptedException {@inheritDoc} |
361 |
|
|
*/ |
362 |
|
|
public void putLast(E e) throws InterruptedException { |
363 |
|
|
if (e == null) throw new NullPointerException(); |
364 |
dl |
1.23 |
Node<E> node = new Node<E>(e); |
365 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
366 |
dl |
1.1 |
lock.lock(); |
367 |
|
|
try { |
368 |
dl |
1.23 |
while (!linkLast(node)) |
369 |
jsr166 |
1.9 |
notFull.await(); |
370 |
dl |
1.1 |
} finally { |
371 |
|
|
lock.unlock(); |
372 |
|
|
} |
373 |
|
|
} |
374 |
|
|
|
375 |
jsr166 |
1.9 |
/** |
376 |
|
|
* @throws NullPointerException {@inheritDoc} |
377 |
|
|
* @throws InterruptedException {@inheritDoc} |
378 |
|
|
*/ |
379 |
|
|
public boolean offerFirst(E e, long timeout, TimeUnit unit) |
380 |
|
|
throws InterruptedException { |
381 |
|
|
if (e == null) throw new NullPointerException(); |
382 |
dl |
1.23 |
Node<E> node = new Node<E>(e); |
383 |
jsr166 |
1.19 |
long nanos = unit.toNanos(timeout); |
384 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
385 |
jsr166 |
1.9 |
lock.lockInterruptibly(); |
386 |
dl |
1.1 |
try { |
387 |
dl |
1.23 |
while (!linkFirst(node)) { |
388 |
jsr166 |
1.9 |
if (nanos <= 0) |
389 |
|
|
return false; |
390 |
|
|
nanos = notFull.awaitNanos(nanos); |
391 |
|
|
} |
392 |
jsr166 |
1.21 |
return true; |
393 |
dl |
1.1 |
} finally { |
394 |
|
|
lock.unlock(); |
395 |
|
|
} |
396 |
|
|
} |
397 |
|
|
|
398 |
jsr166 |
1.9 |
/** |
399 |
|
|
* @throws NullPointerException {@inheritDoc} |
400 |
|
|
* @throws InterruptedException {@inheritDoc} |
401 |
|
|
*/ |
402 |
|
|
public boolean offerLast(E e, long timeout, TimeUnit unit) |
403 |
|
|
throws InterruptedException { |
404 |
|
|
if (e == null) throw new NullPointerException(); |
405 |
dl |
1.23 |
Node<E> node = new Node<E>(e); |
406 |
jsr166 |
1.19 |
long nanos = unit.toNanos(timeout); |
407 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
408 |
jsr166 |
1.9 |
lock.lockInterruptibly(); |
409 |
dl |
1.1 |
try { |
410 |
dl |
1.23 |
while (!linkLast(node)) { |
411 |
jsr166 |
1.9 |
if (nanos <= 0) |
412 |
|
|
return false; |
413 |
|
|
nanos = notFull.awaitNanos(nanos); |
414 |
|
|
} |
415 |
jsr166 |
1.21 |
return true; |
416 |
dl |
1.1 |
} finally { |
417 |
|
|
lock.unlock(); |
418 |
|
|
} |
419 |
|
|
} |
420 |
|
|
|
421 |
jsr166 |
1.9 |
/** |
422 |
|
|
* @throws NoSuchElementException {@inheritDoc} |
423 |
|
|
*/ |
424 |
|
|
public E removeFirst() { |
425 |
|
|
E x = pollFirst(); |
426 |
dl |
1.1 |
if (x == null) throw new NoSuchElementException(); |
427 |
|
|
return x; |
428 |
|
|
} |
429 |
|
|
|
430 |
jsr166 |
1.9 |
/** |
431 |
|
|
* @throws NoSuchElementException {@inheritDoc} |
432 |
|
|
*/ |
433 |
|
|
public E removeLast() { |
434 |
|
|
E x = pollLast(); |
435 |
dl |
1.1 |
if (x == null) throw new NoSuchElementException(); |
436 |
|
|
return x; |
437 |
|
|
} |
438 |
|
|
|
439 |
jsr166 |
1.9 |
public E pollFirst() { |
440 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
441 |
dl |
1.1 |
lock.lock(); |
442 |
|
|
try { |
443 |
jsr166 |
1.9 |
return unlinkFirst(); |
444 |
dl |
1.1 |
} finally { |
445 |
|
|
lock.unlock(); |
446 |
|
|
} |
447 |
|
|
} |
448 |
|
|
|
449 |
jsr166 |
1.9 |
public E pollLast() { |
450 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
451 |
dl |
1.1 |
lock.lock(); |
452 |
|
|
try { |
453 |
jsr166 |
1.9 |
return unlinkLast(); |
454 |
dl |
1.1 |
} finally { |
455 |
|
|
lock.unlock(); |
456 |
|
|
} |
457 |
|
|
} |
458 |
|
|
|
459 |
|
|
public E takeFirst() throws InterruptedException { |
460 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
461 |
dl |
1.1 |
lock.lock(); |
462 |
|
|
try { |
463 |
|
|
E x; |
464 |
|
|
while ( (x = unlinkFirst()) == null) |
465 |
|
|
notEmpty.await(); |
466 |
|
|
return x; |
467 |
|
|
} finally { |
468 |
|
|
lock.unlock(); |
469 |
|
|
} |
470 |
|
|
} |
471 |
|
|
|
472 |
|
|
public E takeLast() throws InterruptedException { |
473 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
474 |
dl |
1.1 |
lock.lock(); |
475 |
|
|
try { |
476 |
|
|
E x; |
477 |
|
|
while ( (x = unlinkLast()) == null) |
478 |
|
|
notEmpty.await(); |
479 |
|
|
return x; |
480 |
|
|
} finally { |
481 |
|
|
lock.unlock(); |
482 |
|
|
} |
483 |
|
|
} |
484 |
|
|
|
485 |
jsr166 |
1.9 |
public E pollFirst(long timeout, TimeUnit unit) |
486 |
dl |
1.1 |
throws InterruptedException { |
487 |
jsr166 |
1.19 |
long nanos = unit.toNanos(timeout); |
488 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
489 |
dl |
1.1 |
lock.lockInterruptibly(); |
490 |
|
|
try { |
491 |
jsr166 |
1.21 |
E x; |
492 |
|
|
while ( (x = unlinkFirst()) == null) { |
493 |
dl |
1.1 |
if (nanos <= 0) |
494 |
jsr166 |
1.9 |
return null; |
495 |
|
|
nanos = notEmpty.awaitNanos(nanos); |
496 |
dl |
1.1 |
} |
497 |
jsr166 |
1.21 |
return x; |
498 |
dl |
1.1 |
} finally { |
499 |
|
|
lock.unlock(); |
500 |
|
|
} |
501 |
|
|
} |
502 |
jsr166 |
1.3 |
|
503 |
jsr166 |
1.9 |
public E pollLast(long timeout, TimeUnit unit) |
504 |
dl |
1.1 |
throws InterruptedException { |
505 |
jsr166 |
1.19 |
long nanos = unit.toNanos(timeout); |
506 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
507 |
dl |
1.1 |
lock.lockInterruptibly(); |
508 |
|
|
try { |
509 |
jsr166 |
1.21 |
E x; |
510 |
|
|
while ( (x = unlinkLast()) == null) { |
511 |
dl |
1.1 |
if (nanos <= 0) |
512 |
jsr166 |
1.9 |
return null; |
513 |
|
|
nanos = notEmpty.awaitNanos(nanos); |
514 |
dl |
1.1 |
} |
515 |
jsr166 |
1.21 |
return x; |
516 |
dl |
1.1 |
} finally { |
517 |
|
|
lock.unlock(); |
518 |
|
|
} |
519 |
|
|
} |
520 |
|
|
|
521 |
jsr166 |
1.9 |
/** |
522 |
|
|
* @throws NoSuchElementException {@inheritDoc} |
523 |
|
|
*/ |
524 |
|
|
public E getFirst() { |
525 |
|
|
E x = peekFirst(); |
526 |
|
|
if (x == null) throw new NoSuchElementException(); |
527 |
|
|
return x; |
528 |
|
|
} |
529 |
|
|
|
530 |
|
|
/** |
531 |
|
|
* @throws NoSuchElementException {@inheritDoc} |
532 |
|
|
*/ |
533 |
|
|
public E getLast() { |
534 |
|
|
E x = peekLast(); |
535 |
|
|
if (x == null) throw new NoSuchElementException(); |
536 |
|
|
return x; |
537 |
|
|
} |
538 |
|
|
|
539 |
|
|
public E peekFirst() { |
540 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
541 |
jsr166 |
1.9 |
lock.lock(); |
542 |
|
|
try { |
543 |
|
|
return (first == null) ? null : first.item; |
544 |
|
|
} finally { |
545 |
|
|
lock.unlock(); |
546 |
|
|
} |
547 |
|
|
} |
548 |
|
|
|
549 |
|
|
public E peekLast() { |
550 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
551 |
jsr166 |
1.9 |
lock.lock(); |
552 |
|
|
try { |
553 |
|
|
return (last == null) ? null : last.item; |
554 |
|
|
} finally { |
555 |
|
|
lock.unlock(); |
556 |
|
|
} |
557 |
|
|
} |
558 |
|
|
|
559 |
|
|
public boolean removeFirstOccurrence(Object o) { |
560 |
|
|
if (o == null) return false; |
561 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
562 |
jsr166 |
1.9 |
lock.lock(); |
563 |
dl |
1.1 |
try { |
564 |
jsr166 |
1.9 |
for (Node<E> p = first; p != null; p = p.next) { |
565 |
|
|
if (o.equals(p.item)) { |
566 |
|
|
unlink(p); |
567 |
|
|
return true; |
568 |
|
|
} |
569 |
dl |
1.1 |
} |
570 |
jsr166 |
1.9 |
return false; |
571 |
dl |
1.1 |
} finally { |
572 |
|
|
lock.unlock(); |
573 |
|
|
} |
574 |
|
|
} |
575 |
|
|
|
576 |
jsr166 |
1.9 |
public boolean removeLastOccurrence(Object o) { |
577 |
|
|
if (o == null) return false; |
578 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
579 |
jsr166 |
1.9 |
lock.lock(); |
580 |
dl |
1.1 |
try { |
581 |
jsr166 |
1.9 |
for (Node<E> p = last; p != null; p = p.prev) { |
582 |
|
|
if (o.equals(p.item)) { |
583 |
|
|
unlink(p); |
584 |
|
|
return true; |
585 |
|
|
} |
586 |
dl |
1.1 |
} |
587 |
jsr166 |
1.9 |
return false; |
588 |
dl |
1.1 |
} finally { |
589 |
|
|
lock.unlock(); |
590 |
|
|
} |
591 |
|
|
} |
592 |
|
|
|
593 |
jsr166 |
1.9 |
// BlockingQueue methods |
594 |
dl |
1.1 |
|
595 |
jsr166 |
1.9 |
/** |
596 |
|
|
* Inserts the specified element at the end of this deque unless it would |
597 |
|
|
* violate capacity restrictions. When using a capacity-restricted deque, |
598 |
|
|
* it is generally preferable to use method {@link #offer(Object) offer}. |
599 |
|
|
* |
600 |
jsr166 |
1.13 |
* <p>This method is equivalent to {@link #addLast}. |
601 |
jsr166 |
1.9 |
* |
602 |
|
|
* @throws IllegalStateException if the element cannot be added at this |
603 |
|
|
* time due to capacity restrictions |
604 |
|
|
* @throws NullPointerException if the specified element is null |
605 |
|
|
*/ |
606 |
|
|
public boolean add(E e) { |
607 |
jsr166 |
1.19 |
addLast(e); |
608 |
|
|
return true; |
609 |
jsr166 |
1.9 |
} |
610 |
|
|
|
611 |
|
|
/** |
612 |
|
|
* @throws NullPointerException if the specified element is null |
613 |
|
|
*/ |
614 |
|
|
public boolean offer(E e) { |
615 |
jsr166 |
1.19 |
return offerLast(e); |
616 |
jsr166 |
1.9 |
} |
617 |
dl |
1.1 |
|
618 |
jsr166 |
1.9 |
/** |
619 |
|
|
* @throws NullPointerException {@inheritDoc} |
620 |
|
|
* @throws InterruptedException {@inheritDoc} |
621 |
|
|
*/ |
622 |
|
|
public void put(E e) throws InterruptedException { |
623 |
jsr166 |
1.19 |
putLast(e); |
624 |
jsr166 |
1.9 |
} |
625 |
dl |
1.1 |
|
626 |
jsr166 |
1.9 |
/** |
627 |
|
|
* @throws NullPointerException {@inheritDoc} |
628 |
|
|
* @throws InterruptedException {@inheritDoc} |
629 |
|
|
*/ |
630 |
jsr166 |
1.7 |
public boolean offer(E e, long timeout, TimeUnit unit) |
631 |
jsr166 |
1.9 |
throws InterruptedException { |
632 |
jsr166 |
1.19 |
return offerLast(e, timeout, unit); |
633 |
jsr166 |
1.9 |
} |
634 |
|
|
|
635 |
|
|
/** |
636 |
|
|
* Retrieves and removes the head of the queue represented by this deque. |
637 |
|
|
* This method differs from {@link #poll poll} only in that it throws an |
638 |
|
|
* exception if this deque is empty. |
639 |
|
|
* |
640 |
|
|
* <p>This method is equivalent to {@link #removeFirst() removeFirst}. |
641 |
|
|
* |
642 |
|
|
* @return the head of the queue represented by this deque |
643 |
|
|
* @throws NoSuchElementException if this deque is empty |
644 |
|
|
*/ |
645 |
|
|
public E remove() { |
646 |
jsr166 |
1.19 |
return removeFirst(); |
647 |
jsr166 |
1.9 |
} |
648 |
|
|
|
649 |
|
|
public E poll() { |
650 |
jsr166 |
1.19 |
return pollFirst(); |
651 |
jsr166 |
1.9 |
} |
652 |
|
|
|
653 |
|
|
public E take() throws InterruptedException { |
654 |
jsr166 |
1.19 |
return takeFirst(); |
655 |
jsr166 |
1.9 |
} |
656 |
|
|
|
657 |
|
|
public E poll(long timeout, TimeUnit unit) throws InterruptedException { |
658 |
jsr166 |
1.19 |
return pollFirst(timeout, unit); |
659 |
jsr166 |
1.9 |
} |
660 |
dl |
1.1 |
|
661 |
|
|
/** |
662 |
jsr166 |
1.9 |
* Retrieves, but does not remove, the head of the queue represented by |
663 |
|
|
* this deque. This method differs from {@link #peek peek} only in that |
664 |
|
|
* it throws an exception if this deque is empty. |
665 |
|
|
* |
666 |
|
|
* <p>This method is equivalent to {@link #getFirst() getFirst}. |
667 |
dl |
1.1 |
* |
668 |
jsr166 |
1.9 |
* @return the head of the queue represented by this deque |
669 |
|
|
* @throws NoSuchElementException if this deque is empty |
670 |
dl |
1.1 |
*/ |
671 |
jsr166 |
1.9 |
public E element() { |
672 |
jsr166 |
1.19 |
return getFirst(); |
673 |
jsr166 |
1.9 |
} |
674 |
|
|
|
675 |
|
|
public E peek() { |
676 |
jsr166 |
1.19 |
return peekFirst(); |
677 |
dl |
1.1 |
} |
678 |
|
|
|
679 |
|
|
/** |
680 |
jsr166 |
1.4 |
* Returns the number of additional elements that this deque can ideally |
681 |
|
|
* (in the absence of memory or resource constraints) accept without |
682 |
dl |
1.1 |
* blocking. This is always equal to the initial capacity of this deque |
683 |
jsr166 |
1.21 |
* less the current {@code size} of this deque. |
684 |
jsr166 |
1.4 |
* |
685 |
|
|
* <p>Note that you <em>cannot</em> always tell if an attempt to insert |
686 |
jsr166 |
1.21 |
* an element will succeed by inspecting {@code remainingCapacity} |
687 |
jsr166 |
1.4 |
* because it may be the case that another thread is about to |
688 |
jsr166 |
1.9 |
* insert or remove an element. |
689 |
dl |
1.1 |
*/ |
690 |
|
|
public int remainingCapacity() { |
691 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
692 |
dl |
1.1 |
lock.lock(); |
693 |
|
|
try { |
694 |
|
|
return capacity - count; |
695 |
|
|
} finally { |
696 |
|
|
lock.unlock(); |
697 |
|
|
} |
698 |
|
|
} |
699 |
|
|
|
700 |
jsr166 |
1.9 |
/** |
701 |
|
|
* @throws UnsupportedOperationException {@inheritDoc} |
702 |
|
|
* @throws ClassCastException {@inheritDoc} |
703 |
|
|
* @throws NullPointerException {@inheritDoc} |
704 |
|
|
* @throws IllegalArgumentException {@inheritDoc} |
705 |
|
|
*/ |
706 |
|
|
public int drainTo(Collection<? super E> c) { |
707 |
jsr166 |
1.21 |
return drainTo(c, Integer.MAX_VALUE); |
708 |
dl |
1.1 |
} |
709 |
|
|
|
710 |
jsr166 |
1.9 |
/** |
711 |
|
|
* @throws UnsupportedOperationException {@inheritDoc} |
712 |
|
|
* @throws ClassCastException {@inheritDoc} |
713 |
|
|
* @throws NullPointerException {@inheritDoc} |
714 |
|
|
* @throws IllegalArgumentException {@inheritDoc} |
715 |
|
|
*/ |
716 |
|
|
public int drainTo(Collection<? super E> c, int maxElements) { |
717 |
|
|
if (c == null) |
718 |
|
|
throw new NullPointerException(); |
719 |
|
|
if (c == this) |
720 |
|
|
throw new IllegalArgumentException(); |
721 |
jsr166 |
1.30 |
if (maxElements <= 0) |
722 |
|
|
return 0; |
723 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
724 |
dl |
1.1 |
lock.lock(); |
725 |
|
|
try { |
726 |
jsr166 |
1.21 |
int n = Math.min(maxElements, count); |
727 |
|
|
for (int i = 0; i < n; i++) { |
728 |
|
|
c.add(first.item); // In this order, in case add() throws. |
729 |
|
|
unlinkFirst(); |
730 |
dl |
1.1 |
} |
731 |
jsr166 |
1.9 |
return n; |
732 |
|
|
} finally { |
733 |
|
|
lock.unlock(); |
734 |
|
|
} |
735 |
|
|
} |
736 |
|
|
|
737 |
|
|
// Stack methods |
738 |
|
|
|
739 |
|
|
/** |
740 |
|
|
* @throws IllegalStateException {@inheritDoc} |
741 |
|
|
* @throws NullPointerException {@inheritDoc} |
742 |
|
|
*/ |
743 |
|
|
public void push(E e) { |
744 |
jsr166 |
1.19 |
addFirst(e); |
745 |
jsr166 |
1.9 |
} |
746 |
|
|
|
747 |
|
|
/** |
748 |
|
|
* @throws NoSuchElementException {@inheritDoc} |
749 |
|
|
*/ |
750 |
|
|
public E pop() { |
751 |
jsr166 |
1.19 |
return removeFirst(); |
752 |
jsr166 |
1.9 |
} |
753 |
|
|
|
754 |
|
|
// Collection methods |
755 |
|
|
|
756 |
jsr166 |
1.11 |
/** |
757 |
|
|
* Removes the first occurrence of the specified element from this deque. |
758 |
|
|
* If the deque does not contain the element, it is unchanged. |
759 |
jsr166 |
1.21 |
* More formally, removes the first element {@code e} such that |
760 |
|
|
* {@code o.equals(e)} (if such an element exists). |
761 |
|
|
* Returns {@code true} if this deque contained the specified element |
762 |
jsr166 |
1.11 |
* (or equivalently, if this deque changed as a result of the call). |
763 |
|
|
* |
764 |
|
|
* <p>This method is equivalent to |
765 |
|
|
* {@link #removeFirstOccurrence(Object) removeFirstOccurrence}. |
766 |
|
|
* |
767 |
|
|
* @param o element to be removed from this deque, if present |
768 |
jsr166 |
1.21 |
* @return {@code true} if this deque changed as a result of the call |
769 |
jsr166 |
1.11 |
*/ |
770 |
jsr166 |
1.9 |
public boolean remove(Object o) { |
771 |
jsr166 |
1.19 |
return removeFirstOccurrence(o); |
772 |
jsr166 |
1.9 |
} |
773 |
|
|
|
774 |
|
|
/** |
775 |
|
|
* Returns the number of elements in this deque. |
776 |
|
|
* |
777 |
|
|
* @return the number of elements in this deque |
778 |
|
|
*/ |
779 |
|
|
public int size() { |
780 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
781 |
jsr166 |
1.9 |
lock.lock(); |
782 |
|
|
try { |
783 |
|
|
return count; |
784 |
dl |
1.1 |
} finally { |
785 |
|
|
lock.unlock(); |
786 |
|
|
} |
787 |
|
|
} |
788 |
|
|
|
789 |
jsr166 |
1.9 |
/** |
790 |
jsr166 |
1.21 |
* Returns {@code true} if this deque contains the specified element. |
791 |
|
|
* More formally, returns {@code true} if and only if this deque contains |
792 |
|
|
* at least one element {@code e} such that {@code o.equals(e)}. |
793 |
jsr166 |
1.9 |
* |
794 |
|
|
* @param o object to be checked for containment in this deque |
795 |
jsr166 |
1.21 |
* @return {@code true} if this deque contains the specified element |
796 |
jsr166 |
1.9 |
*/ |
797 |
|
|
public boolean contains(Object o) { |
798 |
|
|
if (o == null) return false; |
799 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
800 |
dl |
1.1 |
lock.lock(); |
801 |
|
|
try { |
802 |
jsr166 |
1.9 |
for (Node<E> p = first; p != null; p = p.next) |
803 |
|
|
if (o.equals(p.item)) |
804 |
dl |
1.1 |
return true; |
805 |
|
|
return false; |
806 |
|
|
} finally { |
807 |
|
|
lock.unlock(); |
808 |
|
|
} |
809 |
|
|
} |
810 |
|
|
|
811 |
jsr166 |
1.21 |
/* |
812 |
|
|
* TODO: Add support for more efficient bulk operations. |
813 |
|
|
* |
814 |
|
|
* We don't want to acquire the lock for every iteration, but we |
815 |
|
|
* also want other threads a chance to interact with the |
816 |
|
|
* collection, especially when count is close to capacity. |
817 |
|
|
*/ |
818 |
|
|
|
819 |
|
|
// /** |
820 |
|
|
// * Adds all of the elements in the specified collection to this |
821 |
|
|
// * queue. Attempts to addAll of a queue to itself result in |
822 |
|
|
// * {@code IllegalArgumentException}. Further, the behavior of |
823 |
|
|
// * this operation is undefined if the specified collection is |
824 |
|
|
// * modified while the operation is in progress. |
825 |
|
|
// * |
826 |
|
|
// * @param c collection containing elements to be added to this queue |
827 |
|
|
// * @return {@code true} if this queue changed as a result of the call |
828 |
|
|
// * @throws ClassCastException {@inheritDoc} |
829 |
|
|
// * @throws NullPointerException {@inheritDoc} |
830 |
|
|
// * @throws IllegalArgumentException {@inheritDoc} |
831 |
|
|
// * @throws IllegalStateException {@inheritDoc} |
832 |
|
|
// * @see #add(Object) |
833 |
|
|
// */ |
834 |
|
|
// public boolean addAll(Collection<? extends E> c) { |
835 |
|
|
// if (c == null) |
836 |
|
|
// throw new NullPointerException(); |
837 |
|
|
// if (c == this) |
838 |
|
|
// throw new IllegalArgumentException(); |
839 |
|
|
// final ReentrantLock lock = this.lock; |
840 |
|
|
// lock.lock(); |
841 |
|
|
// try { |
842 |
|
|
// boolean modified = false; |
843 |
|
|
// for (E e : c) |
844 |
|
|
// if (linkLast(e)) |
845 |
|
|
// modified = true; |
846 |
|
|
// return modified; |
847 |
|
|
// } finally { |
848 |
|
|
// lock.unlock(); |
849 |
|
|
// } |
850 |
|
|
// } |
851 |
dl |
1.1 |
|
852 |
jsr166 |
1.9 |
/** |
853 |
|
|
* Returns an array containing all of the elements in this deque, in |
854 |
|
|
* proper sequence (from first to last element). |
855 |
|
|
* |
856 |
|
|
* <p>The returned array will be "safe" in that no references to it are |
857 |
|
|
* maintained by this deque. (In other words, this method must allocate |
858 |
|
|
* a new array). The caller is thus free to modify the returned array. |
859 |
jsr166 |
1.10 |
* |
860 |
jsr166 |
1.9 |
* <p>This method acts as bridge between array-based and collection-based |
861 |
|
|
* APIs. |
862 |
|
|
* |
863 |
|
|
* @return an array containing all of the elements in this deque |
864 |
|
|
*/ |
865 |
jsr166 |
1.21 |
@SuppressWarnings("unchecked") |
866 |
dl |
1.1 |
public Object[] toArray() { |
867 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
868 |
dl |
1.1 |
lock.lock(); |
869 |
|
|
try { |
870 |
|
|
Object[] a = new Object[count]; |
871 |
|
|
int k = 0; |
872 |
jsr166 |
1.3 |
for (Node<E> p = first; p != null; p = p.next) |
873 |
dl |
1.1 |
a[k++] = p.item; |
874 |
|
|
return a; |
875 |
|
|
} finally { |
876 |
|
|
lock.unlock(); |
877 |
|
|
} |
878 |
|
|
} |
879 |
|
|
|
880 |
jsr166 |
1.9 |
/** |
881 |
|
|
* Returns an array containing all of the elements in this deque, in |
882 |
|
|
* proper sequence; the runtime type of the returned array is that of |
883 |
|
|
* the specified array. If the deque fits in the specified array, it |
884 |
|
|
* is returned therein. Otherwise, a new array is allocated with the |
885 |
|
|
* runtime type of the specified array and the size of this deque. |
886 |
|
|
* |
887 |
|
|
* <p>If this deque fits in the specified array with room to spare |
888 |
|
|
* (i.e., the array has more elements than this deque), the element in |
889 |
|
|
* the array immediately following the end of the deque is set to |
890 |
jsr166 |
1.21 |
* {@code null}. |
891 |
jsr166 |
1.9 |
* |
892 |
|
|
* <p>Like the {@link #toArray()} method, this method acts as bridge between |
893 |
|
|
* array-based and collection-based APIs. Further, this method allows |
894 |
|
|
* precise control over the runtime type of the output array, and may, |
895 |
|
|
* under certain circumstances, be used to save allocation costs. |
896 |
|
|
* |
897 |
jsr166 |
1.21 |
* <p>Suppose {@code x} is a deque known to contain only strings. |
898 |
jsr166 |
1.9 |
* The following code can be used to dump the deque into a newly |
899 |
jsr166 |
1.21 |
* allocated array of {@code String}: |
900 |
jsr166 |
1.9 |
* |
901 |
jsr166 |
1.29 |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
902 |
jsr166 |
1.9 |
* |
903 |
jsr166 |
1.21 |
* Note that {@code toArray(new Object[0])} is identical in function to |
904 |
|
|
* {@code toArray()}. |
905 |
jsr166 |
1.9 |
* |
906 |
|
|
* @param a the array into which the elements of the deque are to |
907 |
|
|
* be stored, if it is big enough; otherwise, a new array of the |
908 |
|
|
* same runtime type is allocated for this purpose |
909 |
|
|
* @return an array containing all of the elements in this deque |
910 |
|
|
* @throws ArrayStoreException if the runtime type of the specified array |
911 |
|
|
* is not a supertype of the runtime type of every element in |
912 |
|
|
* this deque |
913 |
|
|
* @throws NullPointerException if the specified array is null |
914 |
|
|
*/ |
915 |
jsr166 |
1.21 |
@SuppressWarnings("unchecked") |
916 |
dl |
1.1 |
public <T> T[] toArray(T[] a) { |
917 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
918 |
dl |
1.1 |
lock.lock(); |
919 |
|
|
try { |
920 |
|
|
if (a.length < count) |
921 |
jsr166 |
1.21 |
a = (T[])java.lang.reflect.Array.newInstance |
922 |
|
|
(a.getClass().getComponentType(), count); |
923 |
dl |
1.1 |
|
924 |
|
|
int k = 0; |
925 |
jsr166 |
1.3 |
for (Node<E> p = first; p != null; p = p.next) |
926 |
dl |
1.1 |
a[k++] = (T)p.item; |
927 |
|
|
if (a.length > k) |
928 |
|
|
a[k] = null; |
929 |
|
|
return a; |
930 |
|
|
} finally { |
931 |
|
|
lock.unlock(); |
932 |
|
|
} |
933 |
|
|
} |
934 |
|
|
|
935 |
|
|
public String toString() { |
936 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
937 |
dl |
1.1 |
lock.lock(); |
938 |
|
|
try { |
939 |
jsr166 |
1.24 |
Node<E> p = first; |
940 |
|
|
if (p == null) |
941 |
|
|
return "[]"; |
942 |
|
|
|
943 |
|
|
StringBuilder sb = new StringBuilder(); |
944 |
|
|
sb.append('['); |
945 |
|
|
for (;;) { |
946 |
|
|
E e = p.item; |
947 |
|
|
sb.append(e == this ? "(this Collection)" : e); |
948 |
|
|
p = p.next; |
949 |
|
|
if (p == null) |
950 |
|
|
return sb.append(']').toString(); |
951 |
|
|
sb.append(',').append(' '); |
952 |
|
|
} |
953 |
dl |
1.1 |
} finally { |
954 |
|
|
lock.unlock(); |
955 |
|
|
} |
956 |
|
|
} |
957 |
|
|
|
958 |
|
|
/** |
959 |
|
|
* Atomically removes all of the elements from this deque. |
960 |
|
|
* The deque will be empty after this call returns. |
961 |
|
|
*/ |
962 |
|
|
public void clear() { |
963 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
964 |
dl |
1.1 |
lock.lock(); |
965 |
|
|
try { |
966 |
jsr166 |
1.21 |
for (Node<E> f = first; f != null; ) { |
967 |
|
|
f.item = null; |
968 |
|
|
Node<E> n = f.next; |
969 |
|
|
f.prev = null; |
970 |
|
|
f.next = null; |
971 |
|
|
f = n; |
972 |
|
|
} |
973 |
dl |
1.1 |
first = last = null; |
974 |
|
|
count = 0; |
975 |
|
|
notFull.signalAll(); |
976 |
|
|
} finally { |
977 |
|
|
lock.unlock(); |
978 |
|
|
} |
979 |
|
|
} |
980 |
|
|
|
981 |
|
|
/** |
982 |
|
|
* Returns an iterator over the elements in this deque in proper sequence. |
983 |
jsr166 |
1.9 |
* The elements will be returned in order from first (head) to last (tail). |
984 |
jsr166 |
1.26 |
* |
985 |
|
|
* <p>The returned iterator is a "weakly consistent" iterator that |
986 |
jsr166 |
1.22 |
* will never throw {@link java.util.ConcurrentModificationException |
987 |
jsr166 |
1.26 |
* ConcurrentModificationException}, and guarantees to traverse |
988 |
|
|
* elements as they existed upon construction of the iterator, and |
989 |
|
|
* may (but is not guaranteed to) reflect any modifications |
990 |
|
|
* subsequent to construction. |
991 |
dl |
1.1 |
* |
992 |
jsr166 |
1.9 |
* @return an iterator over the elements in this deque in proper sequence |
993 |
dl |
1.1 |
*/ |
994 |
|
|
public Iterator<E> iterator() { |
995 |
|
|
return new Itr(); |
996 |
|
|
} |
997 |
|
|
|
998 |
|
|
/** |
999 |
dl |
1.14 |
* Returns an iterator over the elements in this deque in reverse |
1000 |
|
|
* sequential order. The elements will be returned in order from |
1001 |
|
|
* last (tail) to first (head). |
1002 |
jsr166 |
1.26 |
* |
1003 |
|
|
* <p>The returned iterator is a "weakly consistent" iterator that |
1004 |
jsr166 |
1.22 |
* will never throw {@link java.util.ConcurrentModificationException |
1005 |
jsr166 |
1.26 |
* ConcurrentModificationException}, and guarantees to traverse |
1006 |
|
|
* elements as they existed upon construction of the iterator, and |
1007 |
|
|
* may (but is not guaranteed to) reflect any modifications |
1008 |
|
|
* subsequent to construction. |
1009 |
|
|
* |
1010 |
|
|
* @return an iterator over the elements in this deque in reverse order |
1011 |
dl |
1.14 |
*/ |
1012 |
|
|
public Iterator<E> descendingIterator() { |
1013 |
|
|
return new DescendingItr(); |
1014 |
|
|
} |
1015 |
|
|
|
1016 |
|
|
/** |
1017 |
|
|
* Base class for Iterators for LinkedBlockingDeque |
1018 |
dl |
1.1 |
*/ |
1019 |
dl |
1.16 |
private abstract class AbstractItr implements Iterator<E> { |
1020 |
jsr166 |
1.15 |
/** |
1021 |
jsr166 |
1.21 |
* The next node to return in next() |
1022 |
dl |
1.14 |
*/ |
1023 |
jsr166 |
1.28 |
Node<E> next; |
1024 |
dl |
1.1 |
|
1025 |
|
|
/** |
1026 |
|
|
* nextItem holds on to item fields because once we claim that |
1027 |
|
|
* an element exists in hasNext(), we must return item read |
1028 |
|
|
* under lock (in advance()) even if it was in the process of |
1029 |
|
|
* being removed when hasNext() was called. |
1030 |
jsr166 |
1.3 |
*/ |
1031 |
dl |
1.14 |
E nextItem; |
1032 |
dl |
1.1 |
|
1033 |
|
|
/** |
1034 |
|
|
* Node returned by most recent call to next. Needed by remove. |
1035 |
|
|
* Reset to null if this element is deleted by a call to remove. |
1036 |
|
|
*/ |
1037 |
dl |
1.16 |
private Node<E> lastRet; |
1038 |
|
|
|
1039 |
jsr166 |
1.21 |
abstract Node<E> firstNode(); |
1040 |
|
|
abstract Node<E> nextNode(Node<E> n); |
1041 |
|
|
|
1042 |
dl |
1.16 |
AbstractItr() { |
1043 |
jsr166 |
1.21 |
// set to initial position |
1044 |
|
|
final ReentrantLock lock = LinkedBlockingDeque.this.lock; |
1045 |
|
|
lock.lock(); |
1046 |
|
|
try { |
1047 |
|
|
next = firstNode(); |
1048 |
|
|
nextItem = (next == null) ? null : next.item; |
1049 |
|
|
} finally { |
1050 |
|
|
lock.unlock(); |
1051 |
|
|
} |
1052 |
dl |
1.16 |
} |
1053 |
dl |
1.1 |
|
1054 |
|
|
/** |
1055 |
jsr166 |
1.25 |
* Returns the successor node of the given non-null, but |
1056 |
|
|
* possibly previously deleted, node. |
1057 |
|
|
*/ |
1058 |
|
|
private Node<E> succ(Node<E> n) { |
1059 |
|
|
// Chains of deleted nodes ending in null or self-links |
1060 |
|
|
// are possible if multiple interior nodes are removed. |
1061 |
|
|
for (;;) { |
1062 |
|
|
Node<E> s = nextNode(n); |
1063 |
|
|
if (s == null) |
1064 |
|
|
return null; |
1065 |
|
|
else if (s.item != null) |
1066 |
|
|
return s; |
1067 |
|
|
else if (s == n) |
1068 |
|
|
return firstNode(); |
1069 |
|
|
else |
1070 |
|
|
n = s; |
1071 |
|
|
} |
1072 |
|
|
} |
1073 |
|
|
|
1074 |
|
|
/** |
1075 |
jsr166 |
1.21 |
* Advances next. |
1076 |
dl |
1.1 |
*/ |
1077 |
jsr166 |
1.21 |
void advance() { |
1078 |
|
|
final ReentrantLock lock = LinkedBlockingDeque.this.lock; |
1079 |
|
|
lock.lock(); |
1080 |
|
|
try { |
1081 |
|
|
// assert next != null; |
1082 |
jsr166 |
1.25 |
next = succ(next); |
1083 |
jsr166 |
1.21 |
nextItem = (next == null) ? null : next.item; |
1084 |
|
|
} finally { |
1085 |
|
|
lock.unlock(); |
1086 |
|
|
} |
1087 |
|
|
} |
1088 |
dl |
1.1 |
|
1089 |
|
|
public boolean hasNext() { |
1090 |
|
|
return next != null; |
1091 |
|
|
} |
1092 |
|
|
|
1093 |
|
|
public E next() { |
1094 |
|
|
if (next == null) |
1095 |
|
|
throw new NoSuchElementException(); |
1096 |
dl |
1.14 |
lastRet = next; |
1097 |
dl |
1.1 |
E x = nextItem; |
1098 |
|
|
advance(); |
1099 |
|
|
return x; |
1100 |
|
|
} |
1101 |
|
|
|
1102 |
|
|
public void remove() { |
1103 |
dl |
1.14 |
Node<E> n = lastRet; |
1104 |
dl |
1.1 |
if (n == null) |
1105 |
|
|
throw new IllegalStateException(); |
1106 |
dl |
1.14 |
lastRet = null; |
1107 |
|
|
final ReentrantLock lock = LinkedBlockingDeque.this.lock; |
1108 |
|
|
lock.lock(); |
1109 |
|
|
try { |
1110 |
jsr166 |
1.21 |
if (n.item != null) |
1111 |
|
|
unlink(n); |
1112 |
dl |
1.14 |
} finally { |
1113 |
|
|
lock.unlock(); |
1114 |
|
|
} |
1115 |
|
|
} |
1116 |
|
|
} |
1117 |
|
|
|
1118 |
jsr166 |
1.21 |
/** Forward iterator */ |
1119 |
|
|
private class Itr extends AbstractItr { |
1120 |
|
|
Node<E> firstNode() { return first; } |
1121 |
|
|
Node<E> nextNode(Node<E> n) { return n.next; } |
1122 |
dl |
1.36 |
// minimal, unsplittable Spliterator implementation |
1123 |
|
|
public boolean tryAdvance(Consumer<? super E> action) { |
1124 |
|
|
if (hasNext()) { |
1125 |
|
|
action.accept(next()); |
1126 |
|
|
return true; |
1127 |
|
|
} |
1128 |
|
|
return false; |
1129 |
|
|
} |
1130 |
|
|
public void forEach(Consumer<? super E> action) { |
1131 |
|
|
while (hasNext()) |
1132 |
|
|
action.accept(next()); |
1133 |
|
|
} |
1134 |
|
|
public int characteristics() { |
1135 |
|
|
return Spliterator.ORDERED | Spliterator.NONNULL | Spliterator.CONCURRENT; |
1136 |
|
|
} |
1137 |
jsr166 |
1.21 |
} |
1138 |
|
|
|
1139 |
|
|
/** Descending iterator */ |
1140 |
dl |
1.16 |
private class DescendingItr extends AbstractItr { |
1141 |
jsr166 |
1.21 |
Node<E> firstNode() { return last; } |
1142 |
|
|
Node<E> nextNode(Node<E> n) { return n.prev; } |
1143 |
dl |
1.14 |
} |
1144 |
|
|
|
1145 |
dl |
1.36 |
static final class LBDSpliterator<E> implements Spliterator<E> { |
1146 |
|
|
// Similar idea to ConcurrentLinkedQueue spliterator |
1147 |
|
|
static final int MAX_BATCH = 1 << 11; // saturate batch size |
1148 |
|
|
final LinkedBlockingDeque<E> queue; |
1149 |
|
|
Node<E> current; // current node; null until initialized |
1150 |
|
|
int batch; // batch size for splits |
1151 |
|
|
boolean exhausted; // true when no more nodes |
1152 |
|
|
long est; // size estimate |
1153 |
jsr166 |
1.37 |
LBDSpliterator(LinkedBlockingDeque<E> queue) { |
1154 |
dl |
1.36 |
this.queue = queue; |
1155 |
|
|
this.est = queue.size(); |
1156 |
|
|
} |
1157 |
|
|
|
1158 |
|
|
public long estimateSize() { return est; } |
1159 |
|
|
|
1160 |
|
|
public Spliterator<E> trySplit() { |
1161 |
|
|
int n; |
1162 |
|
|
final LinkedBlockingDeque<E> q = this.queue; |
1163 |
|
|
final ReentrantLock lock = q.lock; |
1164 |
|
|
if (!exhausted && (n = batch + 1) > 0 && n <= MAX_BATCH) { |
1165 |
|
|
Object[] a = new Object[batch = n]; |
1166 |
|
|
int i = 0; |
1167 |
|
|
Node<E> p = current; |
1168 |
|
|
lock.lock(); |
1169 |
|
|
try { |
1170 |
|
|
if (p != null || (p = q.first) != null) { |
1171 |
|
|
do { |
1172 |
|
|
if ((a[i] = p.item) != null) |
1173 |
|
|
++i; |
1174 |
|
|
} while ((p = p.next) != null && i < n); |
1175 |
|
|
} |
1176 |
|
|
} finally { |
1177 |
|
|
lock.unlock(); |
1178 |
|
|
} |
1179 |
|
|
if ((current = p) == null) { |
1180 |
|
|
est = 0L; |
1181 |
|
|
exhausted = true; |
1182 |
|
|
} |
1183 |
|
|
else if ((est -= i) <= 0L) |
1184 |
|
|
est = 1L; |
1185 |
|
|
return Collections.arraySnapshotSpliterator |
1186 |
|
|
(a, 0, i, Spliterator.ORDERED | Spliterator.NONNULL | |
1187 |
|
|
Spliterator.CONCURRENT); |
1188 |
|
|
} |
1189 |
|
|
return null; |
1190 |
|
|
} |
1191 |
|
|
|
1192 |
|
|
public void forEach(Consumer<? super E> action) { |
1193 |
|
|
if (action == null) throw new NullPointerException(); |
1194 |
|
|
final LinkedBlockingDeque<E> q = this.queue; |
1195 |
|
|
final ReentrantLock lock = q.lock; |
1196 |
|
|
if (!exhausted) { |
1197 |
|
|
exhausted = true; |
1198 |
|
|
Node<E> p = current; |
1199 |
|
|
do { |
1200 |
|
|
E e = null; |
1201 |
|
|
lock.lock(); |
1202 |
|
|
try { |
1203 |
|
|
if (p == null) |
1204 |
|
|
p = q.first; |
1205 |
|
|
while (p != null) { |
1206 |
|
|
e = p.item; |
1207 |
|
|
p = p.next; |
1208 |
|
|
if (e != null) |
1209 |
|
|
break; |
1210 |
|
|
} |
1211 |
|
|
} finally { |
1212 |
|
|
lock.unlock(); |
1213 |
|
|
} |
1214 |
|
|
if (e != null) |
1215 |
|
|
action.accept(e); |
1216 |
|
|
} while (p != null); |
1217 |
|
|
} |
1218 |
|
|
} |
1219 |
|
|
|
1220 |
|
|
public boolean tryAdvance(Consumer<? super E> action) { |
1221 |
|
|
if (action == null) throw new NullPointerException(); |
1222 |
|
|
final LinkedBlockingDeque<E> q = this.queue; |
1223 |
|
|
final ReentrantLock lock = q.lock; |
1224 |
|
|
if (!exhausted) { |
1225 |
|
|
E e = null; |
1226 |
|
|
lock.lock(); |
1227 |
|
|
try { |
1228 |
|
|
if (current == null) |
1229 |
|
|
current = q.first; |
1230 |
|
|
while (current != null) { |
1231 |
|
|
e = current.item; |
1232 |
|
|
current = current.next; |
1233 |
|
|
if (e != null) |
1234 |
|
|
break; |
1235 |
|
|
} |
1236 |
|
|
} finally { |
1237 |
|
|
lock.unlock(); |
1238 |
|
|
} |
1239 |
|
|
if (e != null) { |
1240 |
|
|
action.accept(e); |
1241 |
|
|
return true; |
1242 |
|
|
} |
1243 |
|
|
exhausted = true; |
1244 |
|
|
} |
1245 |
|
|
return false; |
1246 |
|
|
} |
1247 |
|
|
|
1248 |
|
|
public int characteristics() { |
1249 |
|
|
return Spliterator.ORDERED | Spliterator.NONNULL | |
1250 |
|
|
Spliterator.CONCURRENT; |
1251 |
|
|
} |
1252 |
|
|
} |
1253 |
|
|
|
1254 |
|
|
Spliterator<E> spliterator() { |
1255 |
|
|
return new LBDSpliterator<E>(this); |
1256 |
|
|
} |
1257 |
|
|
public Stream<E> stream() { |
1258 |
|
|
return Streams.stream(spliterator()); |
1259 |
|
|
} |
1260 |
|
|
|
1261 |
|
|
public Stream<E> parallelStream() { |
1262 |
|
|
return Streams.parallelStream(spliterator()); |
1263 |
|
|
} |
1264 |
|
|
|
1265 |
dl |
1.1 |
/** |
1266 |
jsr166 |
1.34 |
* Saves this deque to a stream (that is, serializes it). |
1267 |
dl |
1.1 |
* |
1268 |
|
|
* @serialData The capacity (int), followed by elements (each an |
1269 |
jsr166 |
1.21 |
* {@code Object}) in the proper order, followed by a null |
1270 |
dl |
1.1 |
*/ |
1271 |
|
|
private void writeObject(java.io.ObjectOutputStream s) |
1272 |
|
|
throws java.io.IOException { |
1273 |
jsr166 |
1.21 |
final ReentrantLock lock = this.lock; |
1274 |
dl |
1.1 |
lock.lock(); |
1275 |
|
|
try { |
1276 |
|
|
// Write out capacity and any hidden stuff |
1277 |
|
|
s.defaultWriteObject(); |
1278 |
|
|
// Write out all elements in the proper order. |
1279 |
|
|
for (Node<E> p = first; p != null; p = p.next) |
1280 |
|
|
s.writeObject(p.item); |
1281 |
|
|
// Use trailing null as sentinel |
1282 |
|
|
s.writeObject(null); |
1283 |
|
|
} finally { |
1284 |
|
|
lock.unlock(); |
1285 |
|
|
} |
1286 |
|
|
} |
1287 |
|
|
|
1288 |
|
|
/** |
1289 |
jsr166 |
1.31 |
* Reconstitutes this deque from a stream (that is, deserializes it). |
1290 |
dl |
1.1 |
*/ |
1291 |
|
|
private void readObject(java.io.ObjectInputStream s) |
1292 |
|
|
throws java.io.IOException, ClassNotFoundException { |
1293 |
|
|
s.defaultReadObject(); |
1294 |
|
|
count = 0; |
1295 |
|
|
first = null; |
1296 |
|
|
last = null; |
1297 |
|
|
// Read in all elements and place in queue |
1298 |
|
|
for (;;) { |
1299 |
jsr166 |
1.21 |
@SuppressWarnings("unchecked") |
1300 |
dl |
1.1 |
E item = (E)s.readObject(); |
1301 |
|
|
if (item == null) |
1302 |
|
|
break; |
1303 |
|
|
add(item); |
1304 |
|
|
} |
1305 |
|
|
} |
1306 |
jsr166 |
1.3 |
|
1307 |
dl |
1.1 |
} |