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root/i-scream/projects/cms/source/util/uk/org/iscream/cms/util/Queue.java

Comparing projects/cms/source/util/uk/org/iscream/cms/util/Queue.java (file contents):
Revision 1.14 by tdb, Thu Mar 1 01:05:49 2001 UTC vs.
Revision 1.20 by tdb, Mon Mar 26 17:59:47 2001 UTC

#	Line 1 | Line 1
1		//---PACKAGE DECLARATION---
2	<	package uk.ac.ukc.iscream.util;
2	>	package uk.org.iscream.util;
3
4		//---IMPORTS---
5		import java.util.LinkedList;
6		import java.util.NoSuchElementException;
7		import java.util.Random;
8	<	import uk.ac.ukc.iscream.util.*;
8	>	import uk.org.iscream.util.*;
9
10		/**
11		* A Queue class designed to operate in a multi-threaded environment, with
#	Line 49 | Line 49 | public class Queue {
49		*/
50		public static final int DROP = 3;
51
52	+	/**
53	+	* To allow opposite lookups.
54	+	*/
55	+	public static final String[] algorithms = {"RANDOM", "FIRST", "LAST", "DROP"};
56	+
57		//---STATIC METHODS---
58
59		//---CONSTRUCTORS---
#	Line 92 | Line 97 | public class Queue {
97		// get size before adding to the Queue
98		int s = ((LinkedList) _lists.get(i)).size();
99		// check whether we need to remove an item from the current Queue
100	<	if(_maxSize!=-1 && s==_maxSize && _removeAlgorithm!=DROP) {
100	>	if(_maxSize!=-1 && s>=_maxSize && _removeAlgorithm!=DROP) {
101		// we need to remove an item
102		removeQueueItem((LinkedList) _lists.get(i));
103		}
104		// check if we should add (not if Queue full, and using DROP algorithm)
105	<	if(!(s==_maxSize && _removeAlgorithm==DROP)) {
105	>	if(!(s>=_maxSize && _removeAlgorithm==DROP)) {
106		// add the next item, ensuring we lock
107		synchronized(this) {
108		// LinkedList.add() does the same thing, but this ensures behaviour
#	Line 106 | Line 111 | public class Queue {
111		}
112		// if the queue was empty before the add it is possible
113		// that a consumer is waiting... so we notify them
114	<	if (s == 0) {
115	<	synchronized(((LinkedList) _lists.get(i))) {
111	<	((LinkedList) _lists.get(i)).notifyAll();
112	<	}
114	>	synchronized(((LinkedList) _lists.get(i))) {
115	>	((LinkedList) _lists.get(i)).notifyAll();
116		}
117		}
118		}
#	Line 131 | Line 134 | public class Queue {
134		throw new InvalidQueueException("Requested queue "+queue+" does not exist");
135		}
136		// block if the queue is empty
137	<	if (((LinkedList) _lists.get(queue)).size() == 0) {
138	<	synchronized(((LinkedList) _lists.get(queue))) {
137	>	synchronized(((LinkedList) _lists.get(queue))) {
138	>	if (((LinkedList) _lists.get(queue)).size() == 0) {
139		try { ((LinkedList) _lists.get(queue)).wait(); } catch(Exception e) {}
140		}
141		}
#	Line 201 | Line 204 | public class Queue {
204		if(_maxSize != -1) {
205		status += " maxSize=\""+_maxSize+"\"";
206		}
207	<	status += "</queue>";
207	>	status += "></queue>";
208		return status;
209		}
210
#	Line 242 | Line 245 | public class Queue {
245		*
246		* @return An integer to be passed to the get() method.
247		*/
248	<	public int getQueue() {
248	>	public synchronized int getQueue() {
249		int pos = -1;
250		for(int i=0; i < _lists.size(); i++) {
251		if(_lists.get(i) == null) {
#	Line 266 | Line 269 | public class Queue {
269		*
270		* @param queue The integer identifier for the queue, given by getQueue().
271		*/
272	<	public void removeQueue(int queue) {
272	>	public synchronized void removeQueue(int queue) {
273		_lists.set(queue, null);
274		}
275
#	Line 327 | Line 330 | public class Queue {
330		* Overrides the {@link java.lang.Object#toString() Object.toString()}
331		* method to provide clean logging (every class should have this).
332		*
333	<	* This uses the uk.ac.ukc.iscream.util.FormatName class
333	>	* This uses the uk.org.iscream.util.FormatName class
334		* to format the toString()
335		*
336		* @return the name of this class and its CVS revision.

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