[Jrobin-commits] src/org/jrobin/core RrdNioBackend.java,1.14,1.15

[Sasa M. <sa...@us...>]

Update of /cvsroot/jrobin/src/org/jrobin/core
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv20180/org/jrobin/core

Modified Files:
	RrdNioBackend.java 
Log Message:
Workaround for strange NIO exceptions (finally).

Index: RrdNioBackend.java
===================================================================
RCS file: /cvsroot/jrobin/src/org/jrobin/core/RrdNioBackend.java,v
retrieving revision 1.14
retrieving revision 1.15
diff -C2 -d -r1.14 -r1.15
*** RrdNioBackend.java	16 Jul 2004 08:01:14 -0000	1.14
--- RrdNioBackend.java	16 Jul 2004 14:16:38 -0000	1.15
***************
*** 33,49 ****
  
  /**
!  * JRobin backend which is used to store RRD data to ordinary files on the disk
!  * by using java.nio.* package. This is the default backend engine since JRobin 1.4.0.
   */
  public class RrdNioBackend extends RrdFileBackend {
  	/**
! 	 * Defines if the <code>System.gc()</code> method should be executed when necessary.
! 	 * NIO backend uses large in-memory buffer to cache file data. The buffer remains 'active'
! 	 * (by prohibiting file re-creation, for example) as long as it is not garbage collected.
! 	 * By forcing <code>gc()</code> where appropriate, memory gets freed sooner and file
! 	 * re-creation won't fail.<p>
  	 *
! 	 * The constant is set to true initially and currently there is no API to change it
! 	 * during runtime.<p>
  	 */
  	public static final boolean SHOULD_GC = true;
--- 33,53 ----
  
  /**
!  * JRobin backend which is used to store RRD data to ordinary disk files
!  * by using fast java.nio.* package. This is the default backend engine since JRobin 1.4.0.
   */
  public class RrdNioBackend extends RrdFileBackend {
  	/**
! 	 * Defines <code>System.gc()</code> usage policy for this backend.<p>
  	 *
! 	 * NIO backend uses potentially large in-memory buffer to cache file data.
! 	 * The buffer remains 'active' (by prohibiting file re-creation with the smaller file size)
! 	 * as long as it is not garbage-collected. By forcing <code>System.gc()</code> call where
! 	 * appropriate, this backend will free in-memory buffers sooner and file re-creation won't fail.<p>
! 	 *
! 	 * The constant is set to <b><code>true</code></b> initially and currently there is no
! 	 * API to change it during runtime.
! 	 *
! 	 * Garbage collection will be forced only in some special circumstances.
! 	 * It should not affect the speed of your application significantly.<p>
  	 */
  	public static final boolean SHOULD_GC = true;
***************
*** 51,57 ****
  	static {
  		if(SHOULD_GC) {
! 			Runtime.getRuntime().addShutdownHook(new Thread() {
  				public void run() {
! 					System.gc();
  				}
  			});
--- 55,63 ----
  	static {
  		if(SHOULD_GC) {
! 			final Runtime runtime = Runtime.getRuntime();
! 			runtime.addShutdownHook(new Thread() {
  				public void run() {
! 					runtime.runFinalization();
! 					runtime.gc();
  				}
  			});
***************
*** 68,72 ****
  			throws IOException {
  		super(path, readOnly, lockMode);
! 		map(false, readOnly);
  		this.syncMode = syncMode;
  		if(syncMode == RrdNioBackendFactory.SYNC_BACKGROUND && !readOnly) {
--- 74,78 ----
  			throws IOException {
  		super(path, readOnly, lockMode);
! 		map(readOnly);
  		this.syncMode = syncMode;
  		if(syncMode == RrdNioBackendFactory.SYNC_BACKGROUND && !readOnly) {
***************
*** 75,90 ****
  	}
  
! 	private void map(boolean isShorter, boolean readOnly) throws IOException {
! 		if(isShorter) {
! 			byteBuffer = null;
! 			if(SHOULD_GC) {
! 				System.gc();
! 			}
! 		}
! 		long newLength = getLength();
! 		if(newLength > 0) {
  			FileChannel.MapMode mapMode =
  				readOnly? FileChannel.MapMode.READ_ONLY: FileChannel.MapMode.READ_WRITE;
! 			byteBuffer = channel.map(mapMode, 0, newLength);
  		}
  	}
--- 81,93 ----
  	}
  
! 	private void map(boolean readOnly) throws IOException {
! 		long length = getLength();
! 		if(length > 0) {
  			FileChannel.MapMode mapMode =
  				readOnly? FileChannel.MapMode.READ_ONLY: FileChannel.MapMode.READ_WRITE;
! 			byteBuffer = channel.map(mapMode, 0, length);
! 		}
! 		else {
! 			byteBuffer = null;
  		}
  	}
***************
*** 106,112 ****
  	 */
  	protected void setLength(long newLength) throws IOException {
! 		boolean isShorter = newLength < getLength();
  		super.setLength(newLength);
! 		map(isShorter, false);
  	}
  
--- 109,121 ----
  	 */
  	protected void setLength(long newLength) throws IOException {
! 		if(newLength < getLength()) {
! 			// the file will be truncated
! 			if(SHOULD_GC) {
! 				byteBuffer = null;
! 				System.gc();
! 			}
! 		}
  		super.setLength(newLength);
! 		map(false);
  	}