From bb0ad05d71baa66fe90e5d093b58f0bb76d300de Mon Sep 17 00:00:00 2001
From: David McKnight <dmcknigh@ca.ibm.com>
Date: Thu, 4 Dec 2008 21:28:19 +0000
Subject: [PATCH] [255390] check memory to determine whether to queue

---
 .../core/util/DataElementRemover.java         | 37 ++++++++++++++++---
 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/internal/core/util/DataElementRemover.java b/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/internal/core/util/DataElementRemover.java
index e71aa809a72..529dacdd28a 100644
--- a/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/internal/core/util/DataElementRemover.java
+++ b/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/internal/core/util/DataElementRemover.java
@@ -12,8 +12,8 @@
  * Emily Bruner, Mazen Faraj, Adrian Storisteanu, Li Ding, and Kent Hawley.
  * 
  * Contributors:
- * {Name} (company) - description of contribution.
  *  David McKnight  (IBM)  - [202822] don't need to remove children from map here
+ *  David McKnight  (IBM)  - [255390] check memory to determine whether to queue
  *******************************************************************************/
 
 package org.eclipse.dstore.internal.core.util;
@@ -96,25 +96,48 @@ public class DataElementRemover extends Handler
 		numGCed++;
 	}
 
+	
 	public synchronized void addToQueueForRemoval(DataElement element)
-	{		
+	{
 		synchronized (_queue) 
 		{
-			
+			if(isMemoryThresholdExceeded()) {
+				if(element.isSpirit()) {
+					unmap(element);
+				}
+				
+				// do immediate clearing of queue since we're low on memory
+				clearQueue(true);
+				return;
+			}
 			if (_dataStore.isDoSpirit() && _dataStore == element.getDataStore())
 			{
 				QueueItem item = new QueueItem(element, System.currentTimeMillis());
 				_queue.add(item);
 			}
 		}
+		notifyInput();
+	}
+
+	private boolean isMemoryThresholdExceeded(){
+		// trying to avoid using Java 1.5
+		Runtime runtime = Runtime.getRuntime();
+		long freeMem = runtime.freeMemory();
+
+		if (freeMem < 10000){
+
+			return true;
+		}
+		
+		return false;
 	}
 	
 	public void handle()
 	{
-		clearQueue();
+		clearQueue(false);
 	}
 	
-	public synchronized void clearQueue()
+	public synchronized void clearQueue(boolean force)
 	{
 		synchronized (_queue)
 		{
@@ -139,7 +162,7 @@ public class DataElementRemover extends Handler
 			_dataStore.memLog("Size of queue: " + _queue.size()); //$NON-NLS-1$
 			
 			ArrayList toRefresh = new ArrayList();
-			while (_queue.size() > 0 && System.currentTimeMillis() - ((QueueItem) _queue.getFirst()).timeStamp > _expiryTime)
+			while (_queue.size() > 0 && (force || System.currentTimeMillis() - ((QueueItem) _queue.getFirst()).timeStamp > _expiryTime))
 			{
 				DataElement toBeDisconnected = ((QueueItem) _queue.removeFirst()).dataElement;
 				if (!toBeDisconnected.isSpirit()) 
@@ -149,6 +172,7 @@ public class DataElementRemover extends Handler
 					DataElement parent = toBeDisconnected.getParent();
 					if (!toRefresh.contains(parent))
 					{
+						//System.out.println("disconnect parent:"+parent.getName());
 						toRefresh.add(toBeDisconnected.getParent());
 					}
 						//_dataStore.refresh(toBeDisconnected);
@@ -169,6 +193,7 @@ public class DataElementRemover extends Handler
 			_dataStore.memLog("Elements disconnected so far: " + numDisconnected); //$NON-NLS-1$
 			_dataStore.memLog("Spirit elements cleaned so far: " + numRemoved); //$NON-NLS-1$
 			_dataStore.memLog("DataElements GCed so far: " + numGCed); //$NON-NLS-1$
+			System.gc();
 		}
 	}