diff --git a/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/impl/TempDir.java b/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/impl/TempDir.java
deleted file mode 100644
index eb104aa04ec..00000000000
--- a/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/impl/TempDir.java
+++ /dev/null
@@ -1,111 +0,0 @@
-
-package org.eclipse.birt.data.aggregation.impl;
-
-import java.io.File;
-
-import org.eclipse.birt.data.engine.api.DataEngineThreadLocal;
-
-public class TempDir
-{
-
-	private static TempDir instance;
-
-	private String path;
-
-	private TempDir( String path )
-	{
-		this.path = path;
-	}
-
-	/**
-	 * called one time during starting up the plugin
-	 * @param path
-	 */
-	public static void createInstance( String path )
-	{
-		instance = new TempDir( path );
-	}
-
-	/**
-	 * valid only if createInstance is already called
-	 * @return
-	 */
-	public static TempDir getInstance( )
-	{
-		if( instance == null )
-		{
-			String tempDir = System.getProperty( "java.io.tmpdir" )
-			+ "AggregationPlugin_temp" + File.separator;
-			
-			File f = new File( tempDir );
-			if ( f.exists( ) )
-			{
-				deleteDirectory( f );
-			}
-			instance = new TempDir( tempDir );
-		}
-		return instance;
-	}
-
-	public String getPath( )
-	{
-		if ( DataEngineThreadLocal.getInstance( ).getPathManager( ) != null )
-		{
-			return DataEngineThreadLocal.getInstance( )
-					.getPathManager( )
-					.getTempFileName( "AggregationPlugin_temp", 0, null );
-		}
-		else
-			return path;
-	}
-
-	public static void release( )
-	{
-		if (instance != null)
-		{
-			File f = new File( instance.getPath( ) );
-			if ( f.exists( ) )
-			{
-				deleteDirectory( f );
-			}
-			instance = null;
-		}
-	}
-
-	/**
-	 * 
-	 * @param dir
-	 */
-	private static void deleteDirectory( File dir )
-	{
-		File[] subFiles = dir.listFiles( );
-		if ( subFiles != null )
-		{
-			for ( int i = 0; i < subFiles.length; i++ )
-			{
-				if ( subFiles[i].isDirectory( ) )
-				{
-					deleteDirectory( subFiles[i] );
-				}
-				else
-				{
-					safeDelete( subFiles[i] );
-				}
-
-			}
-		}
-		safeDelete( dir );
-	}
-
-	/**
-	 * 
-	 * @param file
-	 */
-	private static void safeDelete( File file )
-	{
-		if ( !file.delete( ) )
-		{
-			file.deleteOnExit( );
-		}
-	}
-}
diff --git a/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/impl/rank/BaseTopBottomAccumulator.java b/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/impl/rank/BaseTopBottomAccumulator.java
index c46619ad06d..323c0d226b6 100644
--- a/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/impl/rank/BaseTopBottomAccumulator.java
+++ b/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/impl/rank/BaseTopBottomAccumulator.java
@@ -11,10 +11,13 @@
 
 package org.eclipse.birt.data.aggregation.impl.rank;
 
+import java.io.File;
+
 import org.eclipse.birt.data.aggregation.impl.RunningAccumulator;
-import org.eclipse.birt.data.aggregation.impl.TempDir;
+import org.eclipse.birt.data.engine.api.DataEngineThreadLocal;
 import org.eclipse.birt.data.engine.cache.BasicCachedArray;
 import org.eclipse.birt.data.engine.core.DataException;
+import org.eclipse.birt.data.engine.core.security.FileSecurity;
 import org.eclipse.birt.data.engine.i18n.ResourceConstants;
 
 /**
@@ -35,11 +38,23 @@ public abstract class BaseTopBottomAccumulator extends RunningAccumulator {
 	private static Boolean falseValue = Boolean.FALSE;
 	private String tempDir;
 	
-	
-	public BaseTopBottomAccumulator(  )
+	public BaseTopBottomAccumulator( )
 	{
-		this.tempDir = TempDir.getInstance( ).getPath( );
-		targetValue = new BasicCachedArray(tempDir, 0);
+		if ( DataEngineThreadLocal.getInstance( ).getPathManager( ) != null )
+		{
+			tempDir = DataEngineThreadLocal.getInstance( )
+					.getPathManager( )
+					.getTempFileName( "AggregationPlugin_temp",
+							this.hashCode( ),
+							null ) + File.separator;
+		}
+		else
+		{
+			tempDir = System.getProperty( "java.io.tmpdir" )
+					+ "AggregationPlugin_temp" + this.hashCode( )
+					+ File.separator;
+		}
+		targetValue = new BasicCachedArray( tempDir, 0 );
 	}
 
 	/*
@@ -158,4 +173,60 @@ private Boolean populateValue( )
 	 * @return
 	 */
 	protected abstract int adjustNValue( double N );
+	
+	/*
+	 * (non-Javadoc)
+	 * @see org.eclipse.birt.data.engine.api.aggregation.Accumulator#finish()
+	 */
+	public void finish( )
+	{
+		//the calculation has been finish, so we can release the resources
+		if( this.passNo >1 )
+		{
+			File tempFile = new File( tempDir );
+			if ( !FileSecurity.fileExist( tempFile )
+					|| !FileSecurity.fileIsDirectory( tempFile ) )
+			{
+				return;
+			}
+			deleteDirectory( tempFile );			
+		}
+	}
+		
+	/**
+	 * 
+	 * @param dir
+	 */
+	private static void deleteDirectory( File dir )
+	{
+		File[] subFiles = FileSecurity.fileListFiles( dir );
+		if( subFiles != null )
+		{
+			for( int i = 0; i < subFiles.length; i++ )
+			{
+				if( FileSecurity.fileIsDirectory( subFiles[i] ) )
+				{
+					deleteDirectory( subFiles[i] );
+				}
+				else
+				{
+					safeDelete( subFiles[i] );
+				}
+			}
+		}
+		safeDelete( dir );
+	}
+	
+	
+	/**
+	 * 
+	 * @param file
+	 */
+	private static void safeDelete( File file )
+	{
+		if( !FileSecurity.fileDelete( file ) )
+		{
+			FileSecurity.fileDeleteOnExit( file );
+		}
+	}
 }
diff --git a/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/plugin/AggregationPlugin.java b/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/plugin/AggregationPlugin.java
index f8c7ba2203c..86d96dc1019 100644
--- a/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/plugin/AggregationPlugin.java
+++ b/data/org.eclipse.birt.data.aggregation/src/org/eclipse/birt/data/aggregation/plugin/AggregationPlugin.java
@@ -1,10 +1,7 @@
 
 package org.eclipse.birt.data.aggregation.plugin;
 
-import java.io.File;
-
 import org.eclipse.birt.core.plugin.BIRTPlugin;
-import org.eclipse.birt.data.aggregation.impl.TempDir;
 import org.osgi.framework.BundleContext;
 
 public class AggregationPlugin extends BIRTPlugin
@@ -13,15 +10,11 @@ public class AggregationPlugin extends BIRTPlugin
 	public void start( BundleContext context ) throws Exception
 	{
 		super.start( context );
-		String tempDir = System.getProperty( "java.io.tmpdir" )
-				+ "AggregationPlugin_" + this.getBundle( ).hashCode( ) + File.separator;
-		TempDir.createInstance( tempDir );
 	}
 
 	@Override
 	public void stop( BundleContext context ) throws Exception
 	{
-		TempDir.release( );
 		super.stop( context );
 	}
 }