Mega Code Archive
Create a unique hash for Constructor and method
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/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This 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 2.1 of
* the License, or (at your option) any later version.
*
* This software 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 this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.security.DigestOutputStream;
import java.security.MessageDigest;
import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;
/**
* Create a unique hash for
*
* @author <a href="mailto:marc@jboss.org">Marc Fleury</a>
* @version $Revision: 2787 $
*/
@SuppressWarnings("unchecked")
public class MethodHashing {
// Constants -----------------------------------------------------
// Static --------------------------------------------------------
static Map hashMap = new WeakHashMap();
public static Method findMethodByHash(Class clazz, long hash) throws Exception {
Method[] methods = clazz.getDeclaredMethods();
for (int i = 0; i < methods.length; i++) {
if (methodHash(methods[i]) == hash)
return methods[i];
}
if (clazz.getSuperclass() != null) {
return findMethodByHash(clazz.getSuperclass(), hash);
}
return null;
}
public static Constructor findConstructorByHash(Class clazz, long hash) throws Exception {
Constructor[] cons = clazz.getDeclaredConstructors();
for (int i = 0; i < cons.length; i++) {
if (constructorHash(cons[i]) == hash)
return cons[i];
}
if (clazz.getSuperclass() != null) {
return findConstructorByHash(clazz.getSuperclass(), hash);
}
return null;
}
public static long methodHash(Method method) throws Exception {
Class[] parameterTypes = method.getParameterTypes();
String methodDesc = method.getName() + "(";
for (int j = 0; j < parameterTypes.length; j++) {
methodDesc += getTypeString(parameterTypes[j]);
}
methodDesc += ")" + getTypeString(method.getReturnType());
long hash = 0;
ByteArrayOutputStream bytearrayoutputstream = new ByteArrayOutputStream(512);
MessageDigest messagedigest = MessageDigest.getInstance("SHA");
DataOutputStream dataoutputstream = new DataOutputStream(new DigestOutputStream(
bytearrayoutputstream, messagedigest));
dataoutputstream.writeUTF(methodDesc);
dataoutputstream.flush();
byte abyte0[] = messagedigest.digest();
for (int j = 0; j < Math.min(8, abyte0.length); j++)
hash += (long) (abyte0[j] & 0xff) << j * 8;
return hash;
}
public static long constructorHash(Constructor method) throws Exception {
Class[] parameterTypes = method.getParameterTypes();
String methodDesc = method.getName() + "(";
for (int j = 0; j < parameterTypes.length; j++) {
methodDesc += getTypeString(parameterTypes[j]);
}
methodDesc += ")";
long hash = 0;
ByteArrayOutputStream bytearrayoutputstream = new ByteArrayOutputStream(512);
MessageDigest messagedigest = MessageDigest.getInstance("SHA");
DataOutputStream dataoutputstream = new DataOutputStream(new DigestOutputStream(
bytearrayoutputstream, messagedigest));
dataoutputstream.writeUTF(methodDesc);
dataoutputstream.flush();
byte abyte0[] = messagedigest.digest();
for (int j = 0; j < Math.min(8, abyte0.length); j++)
hash += (long) (abyte0[j] & 0xff) << j * 8;
return hash;
}
/**
* Calculate method hashes. This algo is taken from RMI.
*
* @param intf
* @return the map
*/
public static Map getInterfaceHashes(Class intf) {
// Create method hashes
Method[] methods = intf.getDeclaredMethods();
HashMap map = new HashMap();
for (int i = 0; i < methods.length; i++) {
Method method = methods[i];
try {
long hash = methodHash(method);
map.put(method.toString(), new Long(hash));
} catch (Exception e) {
}
}
return map;
}
static String getTypeString(Class cl) {
if (cl == Byte.TYPE) {
return "B";
} else if (cl == Character.TYPE) {
return "C";
} else if (cl == Double.TYPE) {
return "D";
} else if (cl == Float.TYPE) {
return "F";
} else if (cl == Integer.TYPE) {
return "I";
} else if (cl == Long.TYPE) {
return "J";
} else if (cl == Short.TYPE) {
return "S";
} else if (cl == Boolean.TYPE) {
return "Z";
} else if (cl == Void.TYPE) {
return "V";
} else if (cl.isArray()) {
return "[" + getTypeString(cl.getComponentType());
} else {
return "L" + cl.getName().replace('.', '/') + ";";
}
}
/*
* The use of hashCode is not enough to differenciate methods we override the
* hashCode
*
* The hashes are cached in a static for efficiency RO: WeakHashMap needed to
* support undeploy
*/
public static long calculateHash(Method method) {
Map methodHashes = (Map) hashMap.get(method.getDeclaringClass());
if (methodHashes == null) {
methodHashes = getInterfaceHashes(method.getDeclaringClass());
// Copy and add
WeakHashMap newHashMap = new WeakHashMap();
newHashMap.putAll(hashMap);
newHashMap.put(method.getDeclaringClass(), methodHashes);
hashMap = newHashMap;
}
return ((Long) methodHashes.get(method.toString())).longValue();
}
}
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