org.aspectj.weaver.tools.cache.DefaultCacheKeyResolver Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2012 Contributors.
* All rights reserved.
* This program and the accompanying materials are made available
* under the terms of the Eclipse Public License v1.0
* which accompanies this distribution and is available at
* http://eclipse.org/legal/epl-v10.html
*
* Contributors:
* John Kew (vmware) initial implementation
*******************************************************************************/
package org.aspectj.weaver.tools.cache;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.zip.CRC32;
/**
* Naive default class and classloader hashing implementation useful
* for some multi-classloader environments.
*
* This implementation creates classloader scopes of the form:
* "ExampleClassLoaderName.[crc hash]"
*
* And weaved class keys of the form:
* "com.foo.BarClassName.[bytes len][crc].weaved"
*
* And generated class keys of the form:
* "com.foo.BarClassName$AjClosure.generated
*/
public class DefaultCacheKeyResolver implements CacheKeyResolver {
public static final String GENERATED_SUFFIX = ".generated";
public static final String WEAVED_SUFFIX = ".weaved";
/**
* Create a scope from a set of urls and aspect urls. Creates scope
* of the form "ExampleClassLoaderName.[md5sum]" or
* "ExampleClassLoaderName.[crc]"
*
* @param cl the classloader which uses the cache, can be null
* @param aspects the aspects
* @return a unique string for URLClassloaders, otherwise a non-unique classname
*/
public String createClassLoaderScope(ClassLoader cl, List aspects) {
String name = cl != null ? cl.getClass().getSimpleName() : "unknown";
List hashableStrings = new LinkedList();
StringBuilder hashable = new StringBuilder(256);
// Add the list of loader urls to the hash list
if (cl != null && cl instanceof URLClassLoader) {
URL[] urls = ((URLClassLoader) cl).getURLs();
for (int i = 0; i < urls.length; i++) {
hashableStrings.add(urls[i].toString());
}
}
hashableStrings.addAll(aspects);
Collections.sort(hashableStrings);
for (Iterator it = hashableStrings.iterator(); it.hasNext(); ) {
String url = it.next();
hashable.append(url);
}
String hash = null;
byte[] bytes = hashable.toString().getBytes();
hash = crc(bytes);
return name + '.' + hash;
}
private String crc(byte[] input) {
CRC32 crc32 = new CRC32();
crc32.update(input);
return String.valueOf(crc32.getValue());
}
public String getGeneratedRegex() {
return ".*" + GENERATED_SUFFIX;
}
public String getWeavedRegex() {
return ".*" + WEAVED_SUFFIX;
}
/**
* Converts a cache key back to a className
*
* @param key to convert
* @return className, e.g. "com.foo.Bar"
*/
public String keyToClass(String key) {
if (key.endsWith(GENERATED_SUFFIX)) {
return key.replaceAll(GENERATED_SUFFIX + "$", "");
}
if (key.endsWith(WEAVED_SUFFIX)) {
return key.replaceAll("\\.[^.]+" + WEAVED_SUFFIX, "");
}
return key;
}
public CachedClassReference weavedKey(String className, byte[] original_bytes) {
String hash = crc(original_bytes);
return new CachedClassReference(className + "." + hash + WEAVED_SUFFIX, className);
}
public CachedClassReference generatedKey(String className) {
return new CachedClassReference(className + GENERATED_SUFFIX, className);
}
}