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- 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
- * <http://www.apache.org/>.
- */
-
- import java.io.IOException;
- import java.io.InputStream;
- import java.lang.ref.Reference;
- import java.lang.ref.ReferenceQueue;
- import java.lang.ref.SoftReference;
- import java.net.URL;
- import java.net.URLClassLoader;
- import java.util.AbstractMap;
- import java.util.Collections;
- import java.util.HashMap;
- import java.util.HashSet;
- import java.util.Map;
- import java.util.Set;
- 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 1.13 2009/09/09 19:56:20 aclement Exp $
- * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
- * @author David Dixon-Peugh
- */
- public class ClassLoaderRepository implements Repository {
- private static java.lang.ClassLoader bootClassLoader = null;
- private ClassLoaderReference loaderRef;
-
- // Choice of cache...
- private WeakHashMap<URL, SoftReference<JavaClass>> localCache = new WeakHashMap<>();
- private static SoftHashMap /* <URL,JavaClass> */sharedCache = new SoftHashMap(Collections.synchronizedMap(new HashMap<>()));
-
- // For fast translation of the classname *intentionally not static*
- private SoftHashMap /* <String,URL> */nameMap = new SoftHashMap(new HashMap(), false);
-
- public static boolean useSharedCache =
- System.getProperty("org.aspectj.apache.bcel.useSharedCache", "true").equalsIgnoreCase("true");
-
- // Cache not found classes as well to prevent unnecessary file I/O operations
- public static boolean useUnavailableClassesCache =
- System.getProperty("org.aspectj.apache.bcel.useUnavailableClassesCache", "false").equalsIgnoreCase("true");
- // Ignore cache clear requests to not build up the cache over and over again
- public static boolean ignoreCacheClearRequests =
- System.getProperty("org.aspectj.apache.bcel.ignoreCacheClearRequests", "false").equalsIgnoreCase("true");
-
- // Second cache for the unavailable classes
- private static Set<String> unavailableClasses = new HashSet<String>();
-
- private static int cacheHitsShared = 0;
- private static int missSharedEvicted = 0; // Misses in shared cache access due to reference GC
- private long timeManipulatingURLs = 0L;
- private long timeSpentLoading = 0L;
- private int classesLoadedCount = 0;
- private int misses = 0;
- private int cacheHitsLocal = 0;
- private int unavailableClassesCacheHits = 0;
- private int missLocalEvicted = 0; // Misses in local cache access due to reference GC
-
- public ClassLoaderRepository(java.lang.ClassLoader loader) {
- this.loaderRef = new DefaultClassLoaderReference((loader != null) ? loader : getBootClassLoader());
- }
-
- public ClassLoaderRepository(ClassLoaderReference loaderRef) {
- this.loaderRef = loaderRef;
- }
-
- private static synchronized java.lang.ClassLoader getBootClassLoader() {
- if (bootClassLoader == null) {
- bootClassLoader = new URLClassLoader(new URL[0]);
- }
- return bootClassLoader;
- }
-
- // Can track back to its key
- public static class SoftHashMap extends AbstractMap {
- private Map<Object, SpecialValue> map;
- boolean recordMiss = true; // only interested in recording miss stats sometimes
- private ReferenceQueue rq = new ReferenceQueue();
-
- public SoftHashMap(Map<Object, SpecialValue> map) {
- this.map = map;
- }
-
- public SoftHashMap() {
- this(new HashMap());
- }
-
- public SoftHashMap(Map map, boolean b) {
- this(map);
- this.recordMiss = b;
- }
-
- class SpecialValue extends SoftReference {
- private final Object key;
-
- SpecialValue(Object k, Object v) {
- super(v, rq);
- this.key = k;
- }
- }
-
- private void processQueue() {
- SpecialValue sv = null;
- while ((sv = (SpecialValue) rq.poll()) != null) {
- map.remove(sv.key);
- }
- }
-
- @Override
- public Object get(Object key) {
- SpecialValue value = map.get(key);
- if (value == null)
- return null;
- if (value.get() == null) {
- // it got GC'd
- map.remove(value.key);
- if (recordMiss)
- missSharedEvicted++;
- return null;
- } else {
- return value.get();
- }
- }
-
- @Override
- public Object put(Object k, Object v) {
- processQueue();
- return map.put(k, new SpecialValue(k, v));
- }
-
- @Override
- public Set entrySet() {
- return map.entrySet();
- }
-
- @Override
- public void clear() {
- if (!ignoreCacheClearRequests) {
- processQueue();
- map.clear();
- }
- }
-
- @Override
- public int size() {
- processQueue();
- return map.size();
- }
-
- @Override
- public Object remove(Object k) {
- processQueue();
- SpecialValue value = map.remove(k);
- if (value == null)
- return null;
- return value.get();
- }
- }
-
- /**
- * Store a new JavaClass into this repository as a soft reference and return the reference
- */
- private void storeClassAsReference(URL url, JavaClass clazz) {
- if (useSharedCache) {
- clazz.setRepository(null); // can't risk setting repository, we'll get in a pickle!
- sharedCache.put(url, clazz);
- } else {
- clazz.setRepository(this);
- localCache.put(url, new SoftReference<>(clazz));
- }
- }
-
- /**
- * Store a new JavaClass into this Repository.
- */
- public void storeClass(JavaClass clazz) {
- storeClassAsReference(toURL(clazz.getClassName()), clazz);
- }
-
- /**
- * Remove class from repository
- */
- public void removeClass(JavaClass clazz) {
- if (useSharedCache)
- sharedCache.remove(toURL(clazz.getClassName()));
- else
- localCache.remove(toURL(clazz.getClassName()));
- }
-
- /**
- * Find an already defined JavaClass in the local cache.
- */
- public JavaClass findClass(String className) {
- if (useSharedCache)
- return findClassShared(toURL(className));
- else
- return findClassLocal(toURL(className));
- }
-
- private JavaClass findClassLocal(URL url) {
- Object o = localCache.get(url);
- 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) {
- return (JavaClass) sharedCache.get(url);
- }
-
- private URL toURL(String className) {
- URL url = (URL) nameMap.get(className);
- if (url == null) {
- String classFile = className.replace('.', '/');
- url = loaderRef.getClassLoader().getResource(classFile + ".class");
- nameMap.put(className, url);
- }
- return url;
- }
-
- /**
- * Lookup a JavaClass object from the classname provided.
- */
- public JavaClass loadClass(String className) throws ClassNotFoundException {
- // Quick evaluation of unavailable classes to prevent unnecessary file I/O
- if (useUnavailableClassesCache && unavailableClasses.contains(className)) {
- unavailableClassesCacheHits++;
- throw new ClassNotFoundException(className + " not found.");
- }
-
- long time = System.currentTimeMillis();
- java.net.URL url = toURL(className);
- timeManipulatingURLs += (System.currentTimeMillis() - time);
- if (url == null) {
- if (useUnavailableClassesCache) {
- unavailableClasses.add(className);
- }
- throw new ClassNotFoundException(className + " not found - unable to determine URL");
- }
-
- JavaClass clazz = null;
- // Look in the appropriate cache
- if (useSharedCache) {
- clazz = findClassShared(url);
- if (clazz != null) {
- cacheHitsShared++;
- return clazz;
- }
- } else {
- clazz = findClassLocal(url);
- if (clazz != null) {
- cacheHitsLocal++;
- return clazz;
- }
- }
-
- // Didn't find it in either cache
- misses++;
-
- try {
- // Load it
- String classFile = className.replace('.', '/');
- InputStream is = (useSharedCache ? url.openStream() : loaderRef.getClassLoader().getResourceAsStream(
- classFile + ".class"));
- if (is == null) {
- if (useUnavailableClassesCache) {
- unavailableClasses.add(className);
- }
- throw new ClassNotFoundException(className + " not found using url " + url);
- }
- ClassParser parser = new ClassParser(is, className);
- clazz = parser.parse();
-
- // Cache it
- storeClassAsReference(url, clazz);
-
- timeSpentLoading += (System.currentTimeMillis() - time);
- classesLoadedCount++;
- return clazz;
- } catch (IOException e) {
- if (useUnavailableClassesCache) {
- unavailableClasses.add(className);
- }
- throw new ClassNotFoundException(e.toString());
- }
- }
-
- /**
- * Produce a report on cache usage.
- */
- public String report() {
- StringBuilder sb = new StringBuilder();
- sb.append("BCEL repository report.");
- if (useSharedCache)
- sb.append(" (shared cache)");
- else
- sb.append(" (local cache)");
- sb.append(" Total time spent loading: " + timeSpentLoading + "ms.");
- sb.append(" Time spent manipulating URLs: " + timeManipulatingURLs + "ms.");
- sb.append(" Classes loaded: " + classesLoadedCount + ".");
- if (useSharedCache) {
- sb.append(" Shared cache size: " + sharedCache.size());
- sb.append(" Shared cache (hits/missDueToEviction): (" + cacheHitsShared + "/" + missSharedEvicted + ").");
- } else {
- sb.append(" Local cache size: " + localCache.size());
- sb.append(" Local cache (hits/missDueToEviction): (" + cacheHitsLocal + "/" + missLocalEvicted + ").");
- }
- return sb.toString();
- }
-
- /**
- * Returns an array of the stats, for testing, the order is fixed: 0=time spent loading (static) 1=time spent manipulating URLs
- * (static) 2=classes loaded (static) 3=cache hits shared (static) 4=misses in shared due to eviction (static) 5=cache hits
- * local 6=misses in local due to eviction 7=shared cache size
- */
- public long[] reportStats() {
- return new long[] { timeSpentLoading, timeManipulatingURLs, classesLoadedCount, cacheHitsShared, missSharedEvicted,
- cacheHitsLocal, missLocalEvicted, sharedCache.size(), unavailableClassesCacheHits };
- }
-
- /**
- * Reset statistics and clear all caches
- */
- public void reset() {
- timeManipulatingURLs = 0L;
- timeSpentLoading = 0L;
- classesLoadedCount = 0;
- cacheHitsLocal = 0;
- cacheHitsShared = 0;
- missSharedEvicted = 0;
- missLocalEvicted = 0;
- unavailableClassesCacheHits = 0;
- misses = 0;
- clear();
- }
-
- public JavaClass loadClass(Class clazz) throws ClassNotFoundException {
- return loadClass(clazz.getName());
- }
-
- /** Clear all entries from the local cache */
- public void clear() {
- if (!ignoreCacheClearRequests) {
- if (useSharedCache) {
- sharedCache.clear();
- } else {
- localCache.clear();
- }
- unavailableClasses.clear();
- }
- }
-
- }
|