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1
55 package org.lateralnz.common.util;
56
57 import java.io.Serializable  ;
58 import java.util.ArrayList ;
59
60 import org.lateralnz.common.wrapper.IntHolder;
61
62
68 public class Queue implements Serializable , Constants {
69 private InnerArrayList queue = new InnerArrayList();
70 private IntHolder messageIdx = new IntHolder(0);
71 private int cleanupSize = 100;
72 private boolean blocking = false;
73
74 public Queue() {
75 this(100, false);
76 }
77
78 public Queue(boolean blocking) {
79 this(100, blocking);
80 }
81
82 public Queue(int cleanupSize) {
83 this(cleanupSize, false);
84 }
85
86 public Queue(int cleanupSize, boolean blocking) {
87 this.cleanupSize = cleanupSize;
88 this.blocking = blocking;
89 }
90
91 public int getSize() {
92 return queue.size() - messageIdx.value;
93 }
94
95 public synchronized void add(Object obj) {
96 queue.add(obj);
97
98 if (messageIdx.value > cleanupSize) {
99 int removed = queue.remove(0, cleanupSize);
100 messageIdx.value -= removed;
101 }
102
103 if (blocking) {
104 try {
105 notify();
106 }
107 catch (IllegalMonitorStateException itme) {
108 System.err.println("illegal monitor state");
109 }
110 }
111 }
112
113 private boolean available() {
114 if (messageIdx.value >= 0 && messageIdx.value < queue.size()) {
115 return true;
116 }
117 else {
118 return false;
119 }
120 }
121
122 public synchronized Object get() throws InterruptedException {
123 if (blocking) {
124 while (!available()) {
125 wait();
126 }
127 }
128
129 Object rtn = null;
130 int idx = messageIdx.value;
131
132 if (available()) {
133 messageIdx.value++;
134 rtn = queue.get(idx);
135 }
136
137 return rtn;
138 }
139
140
143 private class InnerArrayList extends ArrayList {
144
147 public int remove(int start, int end) {
148 if (start > size()) {
149 return 0;
150 }
151 if (end > size()) {
152 end = size();
153 }
154
155 this.removeRange(start, end);
156 return end - start;
157 }
158 }
159
160 public static final void main(String [] args) throws Exception {
162 final Queue queue = new Queue(true);
163 final ArrayList test = new ArrayList ();
164
165 final int max = 10000;
166
167 Thread t = new Thread () {
168 public void run() {
169 java.util.Random rand = new java.util.Random ();
170 for (int i = 0; i < max; i++) {
171 queue.add("test" + i);
172 try { sleep(rand.nextInt(5)); } catch (Exception e) { }
173 }
174 }
175 };
176
177 for (int i = 0; i < 5; i++) {
178 final int idx = i;
179 Thread l = new Thread () {
180 public void run() {
181 java.util.Random rand = new java.util.Random ();
182 while (true) {
183 try {
184 System.out.println("#" + idx + " listening");
185 Object obj = queue.get();
186 if (obj == null) {
187 System.out.println(">>ERROR<<");
188 System.exit(1);
189 }
190 System.out.println("#" + idx + " got " + obj);
191 test.add(obj);
192 if (test.size() >= max) {
193 System.exit(0);
194 }
195 sleep(rand.nextInt(10));
196 }
197 catch (Exception e) { }
198 }
199 }
200 };
201 l.start();
202 }
203
204 t.start();
205 }
206 } |
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