--- projects/cms/source/util/uk/org/iscream/cms/util/Queue.java	2001/03/14 23:25:29	1.16
+++ projects/cms/source/util/uk/org/iscream/cms/util/Queue.java	2001/05/29 17:02:35	1.22
@@ -1,11 +1,11 @@
 //---PACKAGE DECLARATION---
-package uk.org.iscream.util;
+package uk.org.iscream.cms.server.util;
 
 //---IMPORTS---
 import java.util.LinkedList;
 import java.util.NoSuchElementException;
 import java.util.Random;
-import uk.org.iscream.util.*;
+import uk.org.iscream.cms.server.util.*;
 
 /**
  * A Queue class designed to operate in a multi-threaded environment, with
@@ -14,7 +14,7 @@ import uk.org.iscream.util.*;
  * actually contains some elements.
  *
  * @author  $Author: tdb $
- * @version $Id: Queue.java,v 1.16 2001/03/14 23:25:29 tdb Exp $
+ * @version $Id: Queue.java,v 1.22 2001/05/29 17:02:35 tdb Exp $
  */
 public class Queue {
 
@@ -23,7 +23,7 @@ public class Queue {
     /**
      * The current CVS revision of this class
      */
-    public static final String REVISION = "$Revision: 1.16 $";
+    public static final String REVISION = "$Revision: 1.22 $";
     
     /**
      * Pass to constructor to remove a RANDOM item from
@@ -49,6 +49,11 @@ public class Queue {
      */
     public static final int DROP = 3;
     
+    /**
+     * To allow opposite lookups.
+     */
+    public static final String[] algorithms = {"RANDOM", "FIRST", "LAST", "DROP"};
+    
 //---STATIC METHODS---
 
 //---CONSTRUCTORS---  
@@ -89,26 +94,26 @@ public class Queue {
         for(int i=0; i < _lists.size(); i++) {
             // skip over any gaps left in the list
             if(_lists.get(i) != null) {
-                // get size before adding to the Queue
-                int s = ((LinkedList) _lists.get(i)).size();
-                // check whether we need to remove an item from the current Queue
-                if(_maxSize!=-1 && s==_maxSize && _removeAlgorithm!=DROP) {
-                    // we need to remove an item
-                    removeQueueItem((LinkedList) _lists.get(i));
-                }
-                // check if we should add (not if Queue full, and using DROP algorithm)
-                if(!(s==_maxSize && _removeAlgorithm==DROP)) {
-                    // add the next item, ensuring we lock
-                    synchronized(this) {
-                        // LinkedList.add() does the same thing, but this ensures behaviour
-                        ((LinkedList) _lists.get(i)).addLast(o);
+                synchronized(((LinkedList) _lists.get(i))) {
+                    // get size before adding to the Queue
+                    int s = ((LinkedList) _lists.get(i)).size();
+                    // check whether we need to remove an item from the current Queue
+                    if(_maxSize!=-1 && s>=_maxSize && _removeAlgorithm!=DROP) {
+                        // we need to remove an item
+                        removeQueueItem((LinkedList) _lists.get(i));
                     }
-                }
-                // if the queue was empty before the add it is possible
-                // that a consumer is waiting... so we notify them
-                if (s == 0) {
-                    synchronized(((LinkedList) _lists.get(i))) {
-                        ((LinkedList) _lists.get(i)).notifyAll();
+                    // check if we should add (not if Queue full, and using DROP algorithm)
+                    if(!(s>=_maxSize && _removeAlgorithm==DROP)) {
+                        // add the next item, ensuring we lock
+                        synchronized(this) {
+                            // LinkedList.add() does the same thing, but this ensures behaviour
+                            ((LinkedList) _lists.get(i)).addLast(o);
+                        }
+                        // if the queue was empty before the add it is possible
+                        // that a consumer is waiting... so we notify them
+                        //synchronized(((LinkedList) _lists.get(i))) {
+                            ((LinkedList) _lists.get(i)).notifyAll();
+                        //}
                     }
                 }
             }
@@ -131,8 +136,8 @@ public class Queue {
             throw new InvalidQueueException("Requested queue "+queue+" does not exist");
         }
         // block if the queue is empty
-        if (((LinkedList) _lists.get(queue)).size() == 0) {
-            synchronized(((LinkedList) _lists.get(queue))) {
+        synchronized(((LinkedList) _lists.get(queue))) {
+            if (((LinkedList) _lists.get(queue)).size() == 0) {
                 try { ((LinkedList) _lists.get(queue)).wait(); } catch(Exception e) {}
             }
         }
@@ -242,7 +247,7 @@ public class Queue {
      *
      * @return An integer to be passed to the get() method.
      */
-    public int getQueue() {
+    public synchronized int getQueue() {
         int pos = -1;
         for(int i=0; i < _lists.size(); i++) {
             if(_lists.get(i) == null) {
@@ -266,7 +271,7 @@ public class Queue {
      *
      * @param queue The integer identifier for the queue, given by getQueue().
      */
-    public void removeQueue(int queue) {
+    public synchronized void removeQueue(int queue) {
         _lists.set(queue, null);
     }
     
@@ -327,7 +332,7 @@ public class Queue {
      * Overrides the {@link java.lang.Object#toString() Object.toString()}
      * method to provide clean logging (every class should have this).
      *
-     * This uses the uk.org.iscream.util.FormatName class
+     * This uses the uk.org.iscream.cms.server.util.FormatName class
      * to format the toString()
      *
      * @return the name of this class and its CVS revision.