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root/i-scream/experimental/server/Queue/Queue.java
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Comparing experimental/server/Queue/Queue.java (file contents):
Revision 1.5 by tdb, Tue Jan 23 20:14:09 2001 UTC vs.
Revision 1.8 by tdb, Mon Feb 26 01:05:16 2001 UTC

# Line 1 | Line 1
1   //---PACKAGE DECLARATION---
2 < package uk.ac.ukc.iscream.util;
2 > //package uk.ac.ukc.iscream.util;
3  
4   //---IMPORTS---
5   import java.util.LinkedList;
6   import java.util.NoSuchElementException;
7 < import uk.ac.ukc.iscream.util.*;
7 > //import uk.ac.ukc.iscream.util.*;
8  
9   /**
10   * A Queue class designed to operate in a multi-threaded environment, with
# Line 62 | Line 62 | public class Queue {
62       * This method returns an object from the front of a given queue.
63       * It will block until data exists in the queue if required.
64       *
65 +     * @param The queue to retrieve data from.
66       * @return The object from the front of the queue.
67       * @throws InvalidQueueException if the queue does not exist.
68       */
# Line 95 | Line 96 | public class Queue {
96       * shutdown() type methods that may have problems closing
97       * if the thread of control is waiting on a queue.
98       *
99 <     * @param queue the queue to release
99 >     * @param queue the queue to release.
100       */
101      public void releaseQueue(int queue) {
102          synchronized(((LinkedList) _lists.get(queue))) {
103                  ((LinkedList) _lists.get(queue)).notifyAll();
104          }
105      }
106 +
107 +    /**
108 +     * This method erases the contents of a given queue. This
109 +     * method should be used with care. It can only empty one
110 +     * internal queue, not all of them. This must be called
111 +     * multiple times to empty all queues.
112 +     *
113 +     * @param queue the queue to empty.
114 +     */
115 +    public void clearQueue(int queue) {
116 +        synchronized(this) {
117 +            ((LinkedList) _lists.get(queue)).clear();
118 +        }
119 +    }
120      
121      /**
122 <     * This method returns a textual status of the queues. It
123 <     * is merely for observation, and would most likely be used
124 <     * by a larger "monitoring" component. Information returned
125 <     * includes the current size of each queue, and the total
126 <     * items passed through.
122 >     * This method returns an XML textual status of the queues.
123 >     * It is merely for observation, and would most likely be
124 >     * used by a larger "monitoring" component. Information
125 >     * returned includes the current size of each queue, and
126 >     * the total items passed through.
127       *
128 <     * @return A String message containing status information.
128 >     * @return A String message containing status information in XML format
129       */
130 <    public String status() {
131 <        String status = "";
130 >    public String xmlStatus() {
131 >        String status = "<queue ";
132          for(int i=0; i < _lists.size(); i++) {
133              // check for null entries
134              if(_lists.get(i) != null) {
135 <                status += "Queue number "+i+" contains "+((LinkedList) _lists.get(i)).size()+" elements";
121 <                status += "\n";
135 >                status += "queue"+i+"=\""+((LinkedList) _lists.get(i)).size()+"\" ";
136              }
137              else {
138 <                status += "Slot number "+i+" is currently empty";
125 <                status += "\n";
138 >                status += "queue"+i+"=\"[deleted]\" ";
139              }
140          }
141 <        status += "A total of "+_count+" elements have been added to the queues";
141 >        status += "total=\""+_count+"\"></queue>";
142          return status;
143      }
144      
# Line 136 | Line 149 | public class Queue {
149       *
150       * @param queue The queue number to query.
151       * @return the current size of the queue.
152 +     * @throws InvalidQueueException if the queue does not exist.
153       */
154      public int queueSize(int queue) throws InvalidQueueException {
155          if (queue >= _lists.size() || _lists.get(queue) == null) {
# Line 148 | Line 162 | public class Queue {
162       * Returns the total numer of elements to have passed
163       * through this queue (ie. a counter on the add method).
164       *
165 <     * @return the element-ometer
165 >     * @return the element-ometer.
166       */
167      public int elementCount() {
168          return _count;
# Line 194 | Line 208 | public class Queue {
208      }
209      
210      /**
211 +     * Start a monitor on our own Queue. This will log XML
212 +     * statistics about our Queue to a given Queue (could be
213 +     * the one being monitored).
214 +     *
215 +     * @param interval The long interval, in milliseconds, at which to take samples
216 +     * @param destQueue The queue to monitor to
217 +     * @param name A name to identify this Queue with
218 +     * @return whether we succeeded
219 +     */
220 +    public boolean startMonitor(long interval, Queue destQueue, String name) {
221 +        if(_queueMon == null) {
222 +            // start a monitor
223 +            _queueMon = new QueueMonitor(this, destQueue, interval, name);
224 +            _queueMon.start();
225 +            return true;
226 +        }
227 +        else {
228 +            // already have a monitor running
229 +            return false;
230 +        }
231 +    }
232 +    
233 +    /**
234 +     * Start a monitor on our own Queue. This will log XML
235 +     * statistics about our Queue to this Queue.
236 +     *
237 +     * @param interval The long interval, in milliseconds, at which to take samples
238 +     * @param name A name to identify this Queue with
239 +     * @return whether we succeeded
240 +     */
241 +    public boolean startMonitor(long interval, String name) {
242 +        return startMonitor(interval, this, name);
243 +    }
244 +    
245 +    /**
246 +     * Stop a monitor on our Queue if we have on running.
247 +     *
248 +     * @return whether we succeeded
249 +     */
250 +    public boolean stopMonitor() {
251 +        if(_queueMon != null) {
252 +            // stop a monitor
253 +            _queueMon.shutdown();
254 +            _queueMon = null;
255 +            return true;
256 +        }
257 +        else {
258 +            // no monitor running
259 +            return false;
260 +        }
261 +    }
262 +    
263 +    /**
264       * Overrides the {@link java.lang.Object#toString() Object.toString()}
265       * method to provide clean logging (every class should have this).
266       *
267       * This uses the uk.ac.ukc.iscream.util.FormatName class
268       * to format the toString()
269       *
270 <     * @return the name of this class and its CVS revision
270 >     * @return the name of this class and its CVS revision.
271       */
272      public String toString() {
273          return FormatName.getName(
# Line 225 | Line 292 | public class Queue {
292       * passed through, for statistical purposes.
293       */
294      private int _count = 0;
295 +    
296 +    /**
297 +     * A reference to our QueueMonitor, if we have one.
298 +     */
299 +    private QueueMonitor _queueMon = null;
300      
301      /**
302       * This is the friendly identifier of the

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