/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat, Inc. and/or its affiliates or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat, Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.search.backend.impl.lucene;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.store.LockObtainFailedException;
import org.slf4j.Logger;
import org.hibernate.search.backend.LuceneWork;
import org.hibernate.search.backend.Workspace;
import org.hibernate.search.backend.impl.lucene.works.LuceneWorkVisitor;
import org.hibernate.search.exception.ErrorHandler;
import org.hibernate.search.exception.impl.ErrorContextBuilder;
import org.hibernate.search.util.LoggerFactory;
/**
* A Runnable containing a unit of changes to be applied to a specific index.
* After creation, use addWork(LuceneWork) to fill the changes queue and then
* run it to apply all changes. After run() this object should be discarded.
*
* A new PerDPQueueProcessor is created for each unit of work, expensive
* resources to be shared across multiple transactions should be created once
* in PerDPResources.
*
* @see Runnable
* @see #addWork(LuceneWork)
* @author Sanne Grinovero
*/
class PerDPQueueProcessor implements Runnable {
private static final Logger log = LoggerFactory.make();
private final Workspace workspace;
private final LuceneWorkVisitor worker;
private final ExecutorService executor;
private final boolean exclusiveIndexUsage;
private final List<LuceneWork> workOnWriter = new ArrayList<LuceneWork>();
private final ErrorHandler handler;
// if any work needs batchmode, set corresponding flag to true:
private boolean batchmode = false;
/**
* @param resources All resources for the given DirectoryProvider are collected
* from this wrapping object.
*/
public PerDPQueueProcessor(PerDPResources resources) {
this.worker = resources.getVisitor();
this.workspace = resources.getWorkspace();
this.executor = resources.getExecutor();
this.exclusiveIndexUsage = resources.isExclusiveIndexUsageEnabled();
this.handler = resources.getErrorHandler();
}
/**
* adds a LuceneWork to the internal queue. Can't remove them.
* @param work
*/
public void addWork(LuceneWork work) {
if ( work.isBatch() ) {
batchmode = true;
log.debug( "Batch mode enabled" );
}
workOnWriter.add( work );
}
/**
* Do all workOnWriter on an IndexWriter.
*/
public void run() {
if ( workOnWriter.isEmpty() ) {
return;
}
log.debug( "Opening an IndexWriter for update" );
ErrorContextBuilder builder = new ErrorContextBuilder();
builder.allWorkToBeDone( workOnWriter );
try {
IndexWriter indexWriter = workspace.getIndexWriter( batchmode );
try {
for ( LuceneWork lw : workOnWriter ) {
lw.getWorkDelegate( worker ).performWork( lw, indexWriter );
builder.workCompleted( lw );
}
workspace.commitIndexWriter();
performOptimizations();
}
finally {
if ( ! exclusiveIndexUsage ) workspace.closeIndexWriter();
}
}
catch ( Throwable tw ) {
//needs to be attempted even for out of memory errors, therefore we catch Throwable
log.error( "Unexpected error in Lucene Backend: ", tw );
try {
handler.handle( builder.errorThatOccurred( tw ).createErrorContext() );
workspace.closeIndexWriter();
}
finally {
//LockObtainFailedException is wrapped in a SearchException by the workspace
//LockObtainFailedException should never ever release the lock
if ( ! (tw.getCause() instanceof LockObtainFailedException) ) {
workspace.forceLockRelease();
}
}
}
}
private void performOptimizations() {
//TODO next line is assuming the OptimizerStrategy will need an IndexWriter;
// would be nicer to have the strategy put an OptimizeWork on the queue,
// or just return "yes please" (true) to some method?
//FIXME will not have a chance to trigger when no "add" activity is done.
// this is correct until we enable modification counts for deletions too.
workspace.optimizerPhase();
}
/**
* Each PerDPQueueProcessor is owned by an Executor,
* which contains the threads allowed to execute this.
* @return the Executor which should run this Runnable.
*/
public ExecutorService getOwningExecutor() {
return executor;
}
}