/*
* JasperReports - Free Java Reporting Library.
* Copyright (C) 2001 - 2009 Jaspersoft Corporation. All rights reserved.
* http://www.jaspersoft.com
*
* Unless you have purchased a commercial license agreement from Jaspersoft,
* the following license terms apply:
*
* This program is part of JasperReports.
*
* JasperReports is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JasperReports 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 JasperReports. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Contributors:
* Peter Severin - peter_p_s@users.sourceforge.net
*/
package net.sf.jasperreports.engine.design;
import java.io.Serializable;
import java.util.Map;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.fill.JREvaluator;
import net.sf.jasperreports.engine.util.JRClassLoader;
import net.sf.jasperreports.engine.util.JRProperties;
import org.apache.commons.collections.ReferenceMap;
/**
* @author Teodor Danciu (teodord@users.sourceforge.net)
* @version $Id: JRAbstractJavaCompiler.java 3690 2010-04-06 12:23:17Z shertage $
*/
public abstract class JRAbstractJavaCompiler extends JRAbstractCompiler
{
/**
* Property that indicates whether a legacy fix for a JVM issue related to
* evaluator classes generated by JasperReports is enabled. The fix is
* enabled by default.
*
* Due to the fix, the garbage collector might not be able to collect
* a classloader that loaded JasperReports classes. This would be
* inconvenient in scenarios in which JasperReports classes are repeatedly
* loaded by different classloaders, e.g. when JasperReports is part of
* the classpath of a web application which is often reloaded. In such
* scenarios, set this property to false.
*/
public static final String PROPERTY_EVALUATOR_CLASS_REFERENCE_FIX_ENABLED = JRProperties.PROPERTY_PREFIX +
"evaluator.class.reference.fix.enabled";
// @JVM Crash workaround
// Reference to the loaded class class in a per thread map
private static ThreadLocal classFromBytesRef = new ThreadLocal();
private static final Object CLASS_CACHE_NULL_KEY = new Object();
private static Map classCache = new ReferenceMap(ReferenceMap.WEAK, ReferenceMap.SOFT);
protected JRAbstractJavaCompiler(boolean needsSourceFiles)
{
super(needsSourceFiles);
}
protected JREvaluator loadEvaluator(Serializable compileData, String className) throws JRException
{
JREvaluator evaluator = null;
try
{
Class clazz = getClassFromCache(className);
if (clazz == null)
{
clazz = JRClassLoader.loadClassFromBytes(className, (byte[]) compileData);
putClassInCache(className, clazz);
}
if (JRProperties.getBooleanProperty(PROPERTY_EVALUATOR_CLASS_REFERENCE_FIX_ENABLED))
{
//FIXME multiple classes per thread?
classFromBytesRef.set(clazz);
}
evaluator = (JREvaluator) clazz.newInstance();
}
catch (Exception e)
{
throw new JRException("Error loading expression class : " + className, e);
}
return evaluator;
}
protected static Object classCacheKey()
{
ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
return contextClassLoader == null ? CLASS_CACHE_NULL_KEY : contextClassLoader;
}
protected static synchronized Class getClassFromCache(String className)
{
Object key = classCacheKey();
Map contextMap = (Map) classCache.get(key);
Class cachedClass = null;
if (contextMap != null)
{
cachedClass = (Class) contextMap.get(className);
}
return cachedClass;
}
protected static synchronized void putClassInCache(String className, Class loadedClass)
{
Object key = classCacheKey();
Map contextMap = (Map) classCache.get(key);
if (contextMap == null)
{
contextMap = new ReferenceMap(ReferenceMap.HARD, ReferenceMap.SOFT);
classCache.put(key, contextMap);
}
contextMap.put(className, loadedClass);
}
}