/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.uima.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Properties;
import java.util.Vector;
import org.apache.uima.UIMAFramework;
import org.apache.uima.analysis_engine.AnalysisEngine;
import org.apache.uima.cas.CAS;
import org.apache.uima.cas.impl.CASImpl;
import org.apache.uima.resource.CasDefinition;
import org.apache.uima.resource.CasManager;
import org.apache.uima.resource.ResourceInitializationException;
import org.apache.uima.resource.ResourceManager;
import org.apache.uima.resource.metadata.ProcessingResourceMetaData;
/**
* This class represents a simple pool of {@link CAS} instances. This is useful for multithreaded
* applications, where there is a need for multiple CASes to be processed simultaneously. Because
* CAS creation is expensive, it is a good idea to create a pool of reusable CAS instances at
* initialization time, rather than creating a new CAS each time one is needed.
* <p>
* Clients check-out CAS instances from the pool using the {@link #getCas()} method and check-in CAS
* instances using the {@link #releaseCas(CAS)} method.
*
*
*
*/
public class CasPool {
/**
* resource bundle for log messages
*/
private static final String LOG_RESOURCE_BUNDLE = "org.apache.uima.impl.log_messages";
/**
* current class
*/
private static final Class<CasPool> CLASS_NAME = CasPool.class;
private Vector<CAS> mAllInstances = new Vector<CAS>();
private Vector<CAS> mFreeInstances = new Vector<CAS>();
private int mNumInstances;
/**
* Creates a new CasPool
*
* @param aNumInstances
* the number of CAS instances in the pool
* @param aCollectionOfProcessingResourceMetaData
* a collection of
* {@link ProcessingResourceMetaData} objects.
* @param aPerformanceTuningSettings
* Properties object containing framework performance tuning settings using key names
* defined on {@link UIMAFramework} interface
* @param aResourceManager
* the resource manager to use to resolve import declarations within the metadata
*
* @throws ResourceInitializationException
* if the CAS instances could not be created
*/
public CasPool(int aNumInstances, Collection<? extends ProcessingResourceMetaData> aCollectionOfProcessingResourceMetaData,
Properties aPerformanceTuningSettings, ResourceManager aResourceManager)
throws ResourceInitializationException {
mNumInstances = aNumInstances;
fillPool(aCollectionOfProcessingResourceMetaData, aPerformanceTuningSettings, aResourceManager);
}
/**
* Creates a new CasPool
*
* @param aNumInstances
* the number of CAS instances in the pool
* @param aAnalysisEngine
* the analysis engine that will create the CAS instances and which will later be used to
* process them
*
* @throws ResourceInitializationException
* if the CAS instances could not be created
*/
public CasPool(int aNumInstances, AnalysisEngine aAnalysisEngine)
throws ResourceInitializationException {
mNumInstances = aNumInstances;
ArrayList<ProcessingResourceMetaData> mdList = new ArrayList<ProcessingResourceMetaData>();
mdList.add((ProcessingResourceMetaData) aAnalysisEngine.getMetaData());
fillPool(mdList, aAnalysisEngine.getPerformanceTuningSettings(), aAnalysisEngine
.getResourceManager());
}
/**
* Creates a new CasPool
*
* @param aNumInstances
* the number of CAS instances in the pool
* @param aMetaData
* metadata that includes the type system for the CAS
*
* @throws ResourceInitializationException
* if the CAS instances could not be created
*/
public CasPool(int aNumInstances, ProcessingResourceMetaData aMetaData)
throws ResourceInitializationException {
mNumInstances = aNumInstances;
ArrayList<ProcessingResourceMetaData> mdList = new ArrayList<ProcessingResourceMetaData>();
mdList.add(aMetaData);
fillPool(mdList, null, null);
}
/**
* Creates a new CasPool
*
* @param aNumInstances
* the number of CAS instances in the pool
* @param aMetaData
* metadata that includes the type system for the CAS
*
* @throws ResourceInitializationException
* if the CAS instances could not be created
*/
public CasPool(int aNumInstances, ProcessingResourceMetaData aMetaData,
ResourceManager aResourceManager) throws ResourceInitializationException {
mNumInstances = aNumInstances;
ArrayList<ProcessingResourceMetaData> mdList = new ArrayList<ProcessingResourceMetaData>();
mdList.add(aMetaData);
fillPool(mdList, null, aResourceManager);
}
/**
* Creates a new CasPool.
* TODO: do we need this method AND the one that takes a CasManager?
*
* @param aNumInstances
* the number of CAS instances in the pool
* @param aCasDefinition
* the Cas definition, which includes the type system, type priorities, and indexes for
* the CASes in the pool.
* @param aPerformanceTuningSettings
* Properties object containing framework performance tuning settings using key names
* defined on {@link UIMAFramework} interface
*/
public CasPool(int aNumInstances, CasDefinition aCasDefinition,
Properties aPerformanceTuningSettings) throws ResourceInitializationException {
mNumInstances = aNumInstances;
fillPool(aCasDefinition, aPerformanceTuningSettings);
}
/**
* Creates a new CasPool
*
* @param aNumInstances
* the number of CAS instances in the pool
* @param aCasManager
* CAS Manager that will be used to create the CAS. The CAS Manager
* holds the CAS Definition. Also all CASes created from the same
* CAS Manager will share identical TypeSystem objects.
* @param aPerformanceTuningSettings
* Properties object containing framework performance tuning settings using key names
* defined on {@link UIMAFramework} interface
*/
public CasPool(int aNumInstances, CasManager aCasManager,
Properties aPerformanceTuningSettings) throws ResourceInitializationException {
mNumInstances = aNumInstances;
fillPool(aCasManager, aPerformanceTuningSettings);
}
/**
* Checks out a CAS from the pool.
*
* @return a CAS instance. Returns <code>null</code> if none are available (in which case the
* client may {@link Object#wait()} on this object in order to be notified when an
* instance becomes available).
*/
public synchronized CAS getCas() {
if (!mFreeInstances.isEmpty()) {
return (CAS) mFreeInstances.remove(0);
} else {
// no instances available
return null;
}
}
/**
* Checks in a CAS to the pool. This automatically calls the {@link CAS#reset()} method, to ensure
* that when the CAS is later retrieved from the pool it will be ready to use. Also notifies other
* Threads that may be waiting for an instance to become available.
*
* @param aCas
* the Cas to release
*/
public synchronized void releaseCas(CAS aCas) {
// note the pool stores references to the InitialView of each CAS
CAS cas = aCas.getView(CAS.NAME_DEFAULT_SOFA);
// make sure this CAS actually belongs to this pool and is checked out
if (!mAllInstances.contains(cas) || mFreeInstances.contains(cas)) {
UIMAFramework.getLogger(CLASS_NAME).logrb(Level.WARNING, CLASS_NAME.getName(), "releaseCas",
LOG_RESOURCE_BUNDLE, "UIMA_return_cas_to_pool__WARNING");
} else {
// reset CAS
cas.reset();
// restore the ClassLoader and unlock the CAS, since release() can be called
// from within a CAS Multiplier.
((CASImpl)cas).restoreClassLoaderUnlockCas();
// Add the CAS to the end of the free instances List
mFreeInstances.add(cas);
}
// Notify any threads waiting on this object
notifyAll();
}
/**
* Checks out a CAS from the pool. If none is currently available, wait for the specified amount
* of time for one to be checked in.
*
* @param aTimeout
* the time to wait in milliseconds. A value of <=0 will wait forever.
*
* @return a CAS instance. Returns <code>null</code> if none are available within the specified
* timeout period.
*/
public synchronized CAS getCas(long aTimeout) {
// long startTime = new Date().getTime();
long startTime = System.currentTimeMillis();
CAS cas;
while ((cas = getCas()) == null) {
try {
wait(aTimeout);
} catch (InterruptedException e) {
}
// if (aTimeout > 0 && (new Date().getTime() - startTime) >= aTimeout) {
if (aTimeout > 0 && (System.currentTimeMillis() - startTime) >= aTimeout) {
// Timeout has expired
return null;
}
}
return cas;
}
/**
* Gets the size of this pool (the total number of CAS instances that it can hold).
*
* @return the size of this pool
*/
public int getSize() {
return mNumInstances;
}
/**
* Gets the number of CASes currently available in this pool.
* @return the numberof available CASes
*/
public int getNumAvailable() {
return getFreeInstances().size();
}
/**
* @param componentDescriptionsOrMetaData
* @param performanceTuningSettings
* @param resourceManager
*/
private void fillPool(Collection<? extends ProcessingResourceMetaData> mdList, Properties performanceTuningSettings,
ResourceManager resourceManager) throws ResourceInitializationException {
CasDefinition casDef = new CasDefinition(mdList, resourceManager);
fillPool(casDef, performanceTuningSettings);
}
private void fillPool(CasDefinition casDef, Properties performanceTuningSettings)
throws ResourceInitializationException {
// create first CAS from metadata
CAS c0 = CasCreationUtils.createCas(casDef, performanceTuningSettings);
// set owner so cas.release() can return it to the pool
((CASImpl) c0).setOwner(casDef.getCasManager());
mAllInstances.add(c0);
mFreeInstances.add(c0);
// create additional CASes that share same type system
for (int i = 1; i < mNumInstances; i++) {
CAS c = CasCreationUtils.createCas(casDef, performanceTuningSettings, c0.getTypeSystem());
((CASImpl) c).setOwner(casDef.getCasManager());
mAllInstances.add(c);
mFreeInstances.add(c);
}
}
private void fillPool(CasManager casManager, Properties performanceTuningSettings)
throws ResourceInitializationException {
// create additional CASes that share same type system
for (int i = 0; i < mNumInstances; i++) {
CAS c = casManager.createNewCas(performanceTuningSettings);
((CASImpl) c).setOwner(casManager);
mAllInstances.add(c);
mFreeInstances.add(c);
}
}
protected Vector<CAS> getAllInstances() {
return mAllInstances;
}
protected Vector<CAS> getFreeInstances() {
return mFreeInstances;
}
}