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1
4 package demo.sharedqueue;
5
6 import java.net.InetAddress  ;
7 import java.net.UnknownHostException ;
8 import java.util.Collections ;
9 import java.util.HashMap ;
10 import java.util.LinkedList ;
11 import java.util.List ;
12 import java.util.ListIterator ;
13 import java.util.Random ;
14
15 public class Queue {
16 private List queue = Collections.synchronizedList(new LinkedList ());
17 private List workers = Collections.synchronizedList(new LinkedList ());
18 private List completedJobs = Collections.synchronizedList(new LinkedList ());
19 private int nextJobId;
20 private int port;
21 private static final int MAX_HISTORY_LENGTH = 15;
22 private static final int MAX_QUEUE_LENGTH = 150;
23
24 public Queue(int port) {
25 this.port = port;
26 this.nextJobId = 1;
27 }
28
29 public Job getJob() {
30 synchronized (queue) {
31 while (queue.size() == 0) {
32 try {
33 queue.wait();
34 }
35 catch (InterruptedException e) {
36 throw new RuntimeException (e);
37 }
38 }
39 return (Job) queue.remove(0);
40 }
41 }
42
43 public String getXmlData() {
44 String data = "<workqueue>";
46 synchronized (queue) {
47 ListIterator i = queue.listIterator();
48 while (i.hasNext()) {
49 Job job = (Job) i.next();
50 data += job.toXml();
51 }
52 }
53 data += "</workqueue>";
54
55 data += "<completed>";
57 synchronized (completedJobs) {
58 ListIterator i = completedJobs.listIterator();
59 while (i.hasNext()) {
60 Job job = (Job) i.next();
61 data += job.toXml();
62 }
63 }
64 data += "</completed>";
65
66 data += "<consumers>";
68 synchronized (workers) {
69 ListIterator i = workers.listIterator();
70 while (i.hasNext()) {
71 Worker worker = (Worker) i.next();
72 data += worker.toXml();
73 }
74 }
75 data += "</consumers>";
76 return data;
77 }
78
79 public Worker createWorker(String nodeId) {
80 synchronized (workers) {
81 Worker worker = new Worker(this, port, nodeId);
82 workers.add(worker);
83 Thread t = new Thread (worker);
84 t.setDaemon(true);
85 t.start();
86 return worker;
87 }
88 }
89
90 public Worker getWorker(String nodeId) {
91 synchronized (workers) {
92 ListIterator i = workers.listIterator();
93 while (i.hasNext()) {
94 Worker worker = (Worker) i.next();
95 if (worker.getNodeId().equals(nodeId)) {
96 return worker;
97 }
98 }
99 }
100 return null;
101 }
102
103 public void log(Job job) {
104 synchronized (completedJobs) {
105 completedJobs.add(0, job);
106 if (completedJobs.size() > MAX_HISTORY_LENGTH) {
107 completedJobs.remove(completedJobs.size() - 1);
108 }
109 }
110 }
111
112 public void reap() {
113 synchronized (workers) {
114 ListIterator i = workers.listIterator();
115 while (i.hasNext()) {
116 Worker worker = (Worker) i.next();
117 if (worker.expire()) {
118 i.remove();
119 }
120 }
121 }
122 }
123
124 public void addJob() {
125 synchronized (queue) {
126 if (queue.size() >= MAX_QUEUE_LENGTH) {
127 return;
128 }
129
130 Job job = new Job(Queue.getHostName() + " " + this.port, this.nextJobId);
131 this.nextJobId = this.nextJobId < 999 ? this.nextJobId + 1 : 1;
132 queue.add(job);
133 queue.notifyAll();
134 }
135 }
136
137 public void addJob(Job job) {
138 synchronized (queue) {
139 queue.add(job);
140 queue.notifyAll();
141 }
142 }
143
144 public static String getHostName() {
145 try {
146 InetAddress addr = InetAddress.getLocalHost();
147 byte[] ipAddr = addr.getAddress();
148 return addr.getHostName();
149 }
150 catch (UnknownHostException e) {
151 return "Unknown";
152 }
153 }
154 }
155 |
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