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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

Showing the changes to java/pkg/sun/misc/Queue.java (1 of 18352 files). Show all

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java/pkg/sun/misc/Queue.java+214−0
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1+/*
2+ * Copyright (c) 1996, 2005, Oracle and/or its affiliates. All rights reserved.
3+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4+ *
5+ * This code is free software; you can redistribute it and/or modify it
6+ * under the terms of the GNU General Public License version 2 only, as
7+ * published by the Free Software Foundation. Oracle designates this
8+ * particular file as subject to the "Classpath" exception as provided
9+ * by Oracle in the LICENSE file that accompanied this code.
10+ *
11+ * This code is distributed in the hope that it will be useful, but WITHOUT
12+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14+ * version 2 for more details (a copy is included in the LICENSE file that
15+ * accompanied this code).
16+ *
17+ * You should have received a copy of the GNU General Public License version
18+ * 2 along with this work; if not, write to the Free Software Foundation,
19+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20+ *
21+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22+ * or visit www.oracle.com if you need additional information or have any
23+ * questions.
24+ */
25+
26+package sun.misc;
27+
28+import java.util.Enumeration;
29+import java.util.NoSuchElementException;
30+
31+/**
32+ * Queue: implements a simple queue mechanism. Allows for enumeration of the
33+ * elements.
34+ *
35+ * @author Herb Jellinek
36+ */
37+
38+public class Queue {
39+
40+ int length = 0;
41+
42+ QueueElement head = null;
43+ QueueElement tail = null;
44+
45+ public Queue() {
46+ }
47+
48+ /**
49+ * Enqueue an object.
50+ */
51+ public synchronized void enqueue(Object obj) {
52+
53+ QueueElement newElt = new QueueElement(obj);
54+
55+ if (head == null) {
56+ head = newElt;
57+ tail = newElt;
58+ length = 1;
59+ } else {
60+ newElt.next = head;
61+ head.prev = newElt;
62+ head = newElt;
63+ length++;
64+ }
65+ notify();
66+ }
67+
68+ /**
69+ * Dequeue the oldest object on the queue. Will wait indefinitely.
70+ *
71+ * @return the oldest object on the queue.
72+ * @exception java.lang.InterruptedException if any thread has
73+ * interrupted this thread.
74+ */
75+ public Object dequeue() throws InterruptedException {
76+ return dequeue(0L);
77+ }
78+
79+ /**
80+ * Dequeue the oldest object on the queue.
81+ * @param timeOut the number of milliseconds to wait for something
82+ * to arrive.
83+ *
84+ * @return the oldest object on the queue.
85+ * @exception java.lang.InterruptedException if any thread has
86+ * interrupted this thread.
87+ */
88+ public synchronized Object dequeue(long timeOut)
89+ throws InterruptedException {
90+
91+ while (tail == null) {
92+ wait(timeOut);
93+ }
94+ QueueElement elt = tail;
95+ tail = elt.prev;
96+ if (tail == null) {
97+ head = null;
98+ } else {
99+ tail.next = null;
100+ }
101+ length--;
102+ return elt.obj;
103+ }
104+
105+ /**
106+ * Is the queue empty?
107+ * @return true if the queue is empty.
108+ */
109+ public synchronized boolean isEmpty() {
110+ return (tail == null);
111+ }
112+
113+ /**
114+ * Returns an enumeration of the elements in Last-In, First-Out
115+ * order. Use the Enumeration methods on the returned object to
116+ * fetch the elements sequentially.
117+ */
118+ public final synchronized Enumeration elements() {
119+ return new LIFOQueueEnumerator(this);
120+ }
121+
122+ /**
123+ * Returns an enumeration of the elements in First-In, First-Out
124+ * order. Use the Enumeration methods on the returned object to
125+ * fetch the elements sequentially.
126+ */
127+ public final synchronized Enumeration reverseElements() {
128+ return new FIFOQueueEnumerator(this);
129+ }
130+
131+ public synchronized void dump(String msg) {
132+ System.err.println(">> "+msg);
133+ System.err.println("["+length+" elt(s); head = "+
134+ (head == null ? "null" : (head.obj)+"")+
135+ " tail = "+(tail == null ? "null" : (tail.obj)+""));
136+ QueueElement cursor = head;
137+ QueueElement last = null;
138+ while (cursor != null) {
139+ System.err.println(" "+cursor);
140+ last = cursor;
141+ cursor = cursor.next;
142+ }
143+ if (last != tail) {
144+ System.err.println(" tail != last: "+tail+", "+last);
145+ }
146+ System.err.println("]");
147+ }
148+}
149+
150+final class FIFOQueueEnumerator implements Enumeration {
151+ Queue queue;
152+ QueueElement cursor;
153+
154+ FIFOQueueEnumerator(Queue q) {
155+ queue = q;
156+ cursor = q.tail;
157+ }
158+
159+ public boolean hasMoreElements() {
160+ return (cursor != null);
161+ }
162+
163+ public Object nextElement() {
164+ synchronized (queue) {
165+ if (cursor != null) {
166+ QueueElement result = cursor;
167+ cursor = cursor.prev;
168+ return result.obj;
169+ }
170+ }
171+ throw new NoSuchElementException("FIFOQueueEnumerator");
172+ }
173+}
174+
175+final class LIFOQueueEnumerator implements Enumeration {
176+ Queue queue;
177+ QueueElement cursor;
178+
179+ LIFOQueueEnumerator(Queue q) {
180+ queue = q;
181+ cursor = q.head;
182+ }
183+
184+ public boolean hasMoreElements() {
185+ return (cursor != null);
186+ }
187+
188+ public Object nextElement() {
189+ synchronized (queue) {
190+ if (cursor != null) {
191+ QueueElement result = cursor;
192+ cursor = cursor.next;
193+ return result.obj;
194+ }
195+ }
196+ throw new NoSuchElementException("LIFOQueueEnumerator");
197+ }
198+}
199+
200+class QueueElement {
201+ QueueElement next = null;
202+ QueueElement prev = null;
203+
204+ Object obj = null;
205+
206+ QueueElement(Object obj) {
207+ this.obj = obj;
208+ }
209+
210+ public String toString() {
211+ return "QueueElement[obj="+obj+(prev == null ? " null" : " prev")+
212+ (next == null ? " null" : " next")+"]";
213+ }
214+}