// IODispatcher.java
// (C) 2009 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 20.03.2009 on http://yacy.net
//
// $LastChangedDate: 2011-06-30 17:37:14 +0200 (Do, 30. Jun 2011) $
// $LastChangedRevision: 7809 $
// $LastChangedBy: orbiter $
//
// LICENSE
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package net.yacy.kelondro.rwi;
import java.io.File;
import java.io.IOException;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Semaphore;
import net.yacy.kelondro.blob.ArrayStack;
import net.yacy.kelondro.logging.Log;
import net.yacy.kelondro.util.MemoryControl;
/**
* this is a concurrent merger that can merge single files that are queued for merging.
* when several ReferenceContainerArray classes host their ReferenceContainer file arrays,
* they may share a single ReferenceContainerMerger object which does the sharing for all
* of them. This is the best way to do the merging, because it does heavy IO access and
* such access should not be performed concurrently, but queued. This class is the
* manaagement class for queueing of merge jobs.
*
* to use this class, first instantiate a object and then start the concurrent execution
* of merging with a call to the start() - method. To shut down all mergings, call terminate()
* only once.
*/
public class IODispatcher extends Thread {
private Semaphore controlQueue;
private final Semaphore termination;
private ArrayBlockingQueue<MergeJob> mergeQueue;
private ArrayBlockingQueue<DumpJob<? extends Reference>> dumpQueue;
//private ReferenceFactory<ReferenceType> factory;
private boolean terminate;
private final int writeBufferSize;
public IODispatcher(final int dumpQueueLength, final int mergeQueueLength, final int writeBufferSize) {
this.termination = new Semaphore(0);
this.controlQueue = new Semaphore(0);
this.dumpQueue = new ArrayBlockingQueue<DumpJob<? extends Reference>>(dumpQueueLength);
this.mergeQueue = new ArrayBlockingQueue<MergeJob>(mergeQueueLength);
this.writeBufferSize = writeBufferSize;
this.terminate = false;
}
public void terminate() {
if (this.termination != null && this.controlQueue != null && isAlive()) {
this.terminate = true;
this.controlQueue.release();
// await termination
try {
this.termination.acquire();
} catch (final InterruptedException e) {
Log.logException(e);
}
}
}
@SuppressWarnings("unchecked")
protected synchronized void dump(final ReferenceContainerCache<? extends Reference> cache, final File file, final ReferenceContainerArray<? extends Reference> array) {
if (this.dumpQueue == null || this.controlQueue == null || !isAlive()) {
Log.logWarning("IODispatcher", "emergency dump of file " + file.getName());
if (!cache.isEmpty()) cache.dump(file, (int) Math.min(MemoryControl.available() / 3, this.writeBufferSize), true);
} else {
@SuppressWarnings("rawtypes")
final
DumpJob<? extends Reference> job = new DumpJob(cache, file, array);
// check if the dispatcher is running
if (isAlive()) {
try {
this.dumpQueue.put(job);
Log.logInfo("IODispatcher", "appended dump job for file " + file.getName());
} catch (final InterruptedException e) {
Log.logException(e);
cache.dump(file, (int) Math.min(MemoryControl.available() / 3, this.writeBufferSize), true);
} finally {
this.controlQueue.release();
}
} else {
job.dump();
Log.logWarning("IODispatcher", "dispatcher is not alive, just dumped file " + file.getName());
}
}
}
protected synchronized int queueLength() {
return (this.controlQueue == null || !isAlive()) ? 0 : this.controlQueue.availablePermits();
}
protected synchronized void merge(final File f1, final File f2, final ReferenceFactory<? extends Reference> factory, final ArrayStack array, final File newFile) {
if (this.mergeQueue == null || this.controlQueue == null || !isAlive()) {
if (f2 == null) {
Log.logWarning("IODispatcher", "emergency rewrite of file " + f1.getName() + " to " + newFile.getName());
} else {
Log.logWarning("IODispatcher", "emergency merge of files " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
}
array.mergeMount(f1, f2, factory, newFile, (int) Math.min(MemoryControl.available() / 3, this.writeBufferSize));
} else {
final MergeJob job = new MergeJob(f1, f2, factory, array, newFile);
if (isAlive()) {
try {
this.mergeQueue.put(job);
if (f2 == null) {
Log.logInfo("IODispatcher", "appended rewrite job of file " + f1.getName() + " to " + newFile.getName());
} else {
Log.logInfo("IODispatcher", "appended merge job of files " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
}
} catch (final InterruptedException e) {
Log.logWarning("IODispatcher", "interrupted: " + e.getMessage(), e);
array.mergeMount(f1, f2, factory, newFile, (int) Math.min(MemoryControl.available() / 3, this.writeBufferSize));
} finally {
this.controlQueue.release();
}
} else {
job.merge();
if (f2 == null) {
Log.logWarning("IODispatcher", "dispatcher not running, merged files " + f1.getName() + " to " + newFile.getName());
} else {
Log.logWarning("IODispatcher", "dispatcher not running, rewrote file " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
}
}
}
}
@Override
public void run() {
MergeJob mergeJob;
DumpJob<? extends Reference> dumpJob;
try {
loop: while (true) try {
this.controlQueue.acquire();
// prefer dump actions to flush memory to disc
if (!this.dumpQueue.isEmpty()) {
File f = null;
try {
dumpJob = this.dumpQueue.take();
f = dumpJob.file;
dumpJob.dump();
} catch (final InterruptedException e) {
Log.logSevere("IODispatcher", "main run job was interrupted (1)", e);
Log.logException(e);
} catch (final Exception e) {
Log.logSevere("IODispatcher", "main run job had errors (1), dump to " + f + " failed.", e);
Log.logException(e);
}
continue loop;
}
// otherwise do a merge operation
if (!this.mergeQueue.isEmpty()) {
File f = null, f1 = null, f2 = null;
try {
mergeJob = this.mergeQueue.take();
f = mergeJob.newFile;
f1 = mergeJob.f1;
f2 = mergeJob.f2;
mergeJob.merge();
} catch (final InterruptedException e) {
Log.logSevere("IODispatcher", "main run job was interrupted (2)", e);
Log.logException(e);
} catch (final Exception e) {
if (f2 == null) {
Log.logSevere("IODispatcher", "main run job had errors (2), dump to " + f + " failed. Input file is " + f1, e);
} else {
Log.logSevere("IODispatcher", "main run job had errors (2), dump to " + f + " failed. Input files are " + f1 + " and " + f2, e);
}
Log.logException(e);
}
continue loop;
}
// check termination
if (this.terminate) {
Log.logInfo("IODispatcher", "caught termination signal");
break;
}
Log.logSevere("IODispatcher", "main loop in bad state, dumpQueue.size() = " + this.dumpQueue.size() + ", mergeQueue.size() = " + this.mergeQueue.size() + ", controlQueue.availablePermits() = " + this.controlQueue.availablePermits());
assert false : "this process statt should not be reached"; // this should never happen
} catch (final Exception e) {
Log.logSevere("IODispatcher", "main run job failed (X)", e);
Log.logException(e);
}
Log.logInfo("IODispatcher", "loop terminated");
} catch (final Exception e) {
Log.logSevere("IODispatcher", "main run job failed (4)", e);
Log.logException(e);
} finally {
Log.logInfo("IODispatcher", "terminating run job");
this.controlQueue = null;
this.dumpQueue = null;
this.mergeQueue = null;
this.termination.release();
}
}
private class DumpJob<ReferenceType extends Reference> {
private final ReferenceContainerCache<ReferenceType> cache;
private final File file;
private final ReferenceContainerArray<ReferenceType> array;
private DumpJob(final ReferenceContainerCache<ReferenceType> cache, final File file, final ReferenceContainerArray<ReferenceType> array) {
this.cache = cache;
this.file = file;
this.array = array;
}
private void dump() {
try {
if (!this.cache.isEmpty()) this.cache.dump(this.file, (int) Math.min(MemoryControl.available() / 3, IODispatcher.this.writeBufferSize), true);
this.array.mountBLOBFile(this.file);
} catch (final IOException e) {
Log.logException(e);
}
}
}
private class MergeJob {
private final File f1, f2, newFile;
private final ArrayStack array;
private final ReferenceFactory<? extends Reference> factory;
private MergeJob(
final File f1,
final File f2,
final ReferenceFactory<? extends Reference> factory,
final ArrayStack array,
final File newFile) {
this.f1 = f1;
this.f2 = f2;
this.factory = factory;
this.newFile = newFile;
this.array = array;
}
private File merge() {
if (!this.f1.exists()) {
Log.logWarning("IODispatcher", "merge of file (1) " + this.f1.getName() + " failed: file does not exists");
return null;
}
if (this.f2 != null && !this.f2.exists()) {
Log.logWarning("IODispatcher", "merge of file (2) " + this.f2.getName() + " failed: file does not exists");
return null;
}
return this.array.mergeMount(this.f1, this.f2, this.factory, this.newFile, (int) Math.min(MemoryControl.available() / 3, IODispatcher.this.writeBufferSize));
}
}
}