org.jboss.resteasy.util.MethodHashing Maven / Gradle / Ivy
package org.jboss.resteasy.util;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.lang.reflect.Method;
import java.security.DigestOutputStream;
import java.security.MessageDigest;
/**
* @author Bill Burke
* @version $Revision: 1 $
*/
public class MethodHashing
{
public static long methodHash(Method method)
throws Exception
{
Class[] parameterTypes = method.getParameterTypes();
StringBuilder methodDesc = new StringBuilder(method.getName()).append("(");
for (int j = 0; j < parameterTypes.length; j++)
{
methodDesc.append(getTypeString(parameterTypes[j]));
}
methodDesc.append(")").append(getTypeString(method.getReturnType()));
return createHash(methodDesc.toString());
}
public static long createHash(String methodDesc)
throws Exception
{
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;
}
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('.', '/') + ";";
}
}
}