package org.aspectj.apache.bcel.util;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache BCEL" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* "Apache BCEL", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* .
*/
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.Reference;
import java.lang.ref.SoftReference;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;
import org.aspectj.apache.bcel.classfile.ClassParser;
import org.aspectj.apache.bcel.classfile.JavaClass;
/**
* The repository maintains information about which classes have
* been loaded.
*
* It loads its data from the ClassLoader implementation
* passed into its constructor.
*
* @see org.aspectj.apache.bcel.Repository
*
* @version $Id: ClassLoaderRepository.java,v 1.7 2006/08/18 14:51:00 acolyer Exp $
* @author M. Dahm
* @author David Dixon-Peugh
*/
public class ClassLoaderRepository implements Repository {
private static java.lang.ClassLoader bootClassLoader = null;
private java.lang.ClassLoader loader;
private WeakHashMap /**/loadedClassesLocalCache = new WeakHashMap();
private static Map /**/loadedUrlsSharedCache = new HashMap();
public static boolean useSharedCache = true;
private static long timeManipulatingURLs = 0L;
private static long timeSpentLoading = 0L;
private static int classesLoadedCount = 0;
private static int cacheHitsShared = 0;
private static int missSharedEvicted = 0; // Misses in shared cache access due to reference GC
private static int misses = 0;
private int cacheHitsLocal = 0;
private int missLocalEvicted = 0; // Misses in local cache access due to reference GC
static {
useSharedCache = System.getProperty("org.aspectj.apache.bcel.useSharedCache","true").equalsIgnoreCase("true");
}
public ClassLoaderRepository( java.lang.ClassLoader loader ) {
this.loader = (loader != null) ? loader : getBootClassLoader();
}
private static synchronized java.lang.ClassLoader getBootClassLoader() {
if (bootClassLoader == null) {
bootClassLoader = new URLClassLoader(new URL[0]);
}
return bootClassLoader;
}
/**
* Store a new JavaClass into this repository as a soft reference and return the reference
*/
private Reference storeClassAsReference( JavaClass clazz ) {
Reference ref = new SoftReference(clazz);
loadedClassesLocalCache.put( clazz.getClassName(), ref);
clazz.setRepository( this );
return ref;
}
/**
* Store a reference in the shared cache
*/
private void storeReferenceShared(URL url, Reference ref) {
if (useSharedCache) loadedUrlsSharedCache.put(url, ref);
}
/**
* Store a new JavaClass into this Repository.
*/
public void storeClass( JavaClass clazz ) {
storeClassAsReference(clazz);
}
/**
* Remove class from repository
*/
public void removeClass(JavaClass clazz) {
loadedClassesLocalCache.remove(clazz.getClassName());
}
/**
* Find an already defined JavaClass in the local cache.
*/
public JavaClass findClass( String className ) {
Object o = loadedClassesLocalCache.get( className );
if (o != null) {
o = ((Reference)o).get();
if (o != null) {
return (JavaClass)o;
} else {
missLocalEvicted++;
}
}
return null;
}
/**
* Find an already defined JavaClass in the shared cache.
*/
private JavaClass findClassShared(URL url) {
if (!useSharedCache) return null;
Object o = (Reference)loadedUrlsSharedCache.get(url);
if (o != null) {
o = ((Reference)o).get();
if (o != null) {
return (JavaClass)o;
} else {
missSharedEvicted++;
}
}
return null;
}
/**
* Lookup a JavaClass object from the Class Name provided.
*/
public JavaClass loadClass( String className ) throws ClassNotFoundException {
String classFile = className.replace('.', '/');
// Check the local cache
JavaClass clazz = findClass(className);
if (clazz != null) { cacheHitsLocal++; return clazz; }
try {
// Work out the URL
long time = System.currentTimeMillis();
java.net.URL url = (useSharedCache?loader.getResource( classFile + ".class" ):null);
if (useSharedCache && url==null) throw new ClassNotFoundException(className + " not found.");
InputStream is = (useSharedCache?url.openStream():loader.getResourceAsStream( classFile + ".class" ));
timeManipulatingURLs += (System.currentTimeMillis() - time);
// Check the shared cache
clazz = findClassShared(url);
if (clazz != null) { cacheHitsShared++; timeSpentLoading+=(System.currentTimeMillis() - time); return clazz; }
// Didn't find it in either cache
misses++;
if (is == null) { // TODO move this up?
throw new ClassNotFoundException(className + " not found.");
}
ClassParser parser = new ClassParser( is, className );
clazz = parser.parse();
// Store it in both caches
Reference ref = storeClassAsReference( clazz );
storeReferenceShared(url,ref);
timeSpentLoading += (System.currentTimeMillis() - time);
classesLoadedCount++;
return clazz;
} catch (IOException e) {
throw new ClassNotFoundException( e.toString() );
}
}
/**
* Produce a report on cache usage.
*/
public String reportAllStatistics() {
StringBuffer sb = new StringBuffer();
sb.append("BCEL repository report.");
if (!useSharedCache) sb.append(" (Shared cache deactivated)");
sb.append(" Total time spent loading: "+timeSpentLoading+"ms.");
sb.append(" Time manipulating URLs: "+timeManipulatingURLs+"ms.");
sb.append(" Classes loaded: "+classesLoadedCount+".");
if (useSharedCache) sb.append(" URL cache (hits/missDueToEviction): ("+cacheHitsShared+"/"+missSharedEvicted+").");
sb.append(" Local cache (hits/missDueToEviction): ("+cacheHitsLocal+"/"+missLocalEvicted+").");
return sb.toString();
}
public int reportLocalCacheHits() {
return cacheHitsLocal;
}
public static int reportSharedCacheHits() {
return cacheHitsShared;
}
/**
* Reset statistics and clear all caches
*/
public void reset() {
timeManipulatingURLs = 0L;
timeSpentLoading = 0L;
classesLoadedCount = 0;
cacheHitsLocal = 0;
cacheHitsShared = 0;
missSharedEvicted = 0;
missLocalEvicted = 0;
misses = 0;
clear();
clearShared();
}
public JavaClass loadClass(Class clazz) throws ClassNotFoundException {
return loadClass(clazz.getName());
}
/** Clear all entries from the local cache */
public void clear() {
loadedClassesLocalCache.clear();
}
/** Clear all entries from the shared cache */
public static void clearShared() {
loadedUrlsSharedCache.clear();
}
}