/*
* Copyright (C) 2012 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jboss.errai;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.security.ProtectionDomain;
import java.util.regex.Pattern;
/**
* A class file "transformer" that ignores the original class definition,
* instead generating a class that is completely empty.
*
* @author Jonathan Fuerth <jfuerth@gmail.com>
*/
public class ClientLocalClassHider implements ClassFileTransformer {
private final Pattern hiddenClassNamePattern;
private final boolean debug;
public ClientLocalClassHider(Pattern hiddenClassNamePattern, boolean debug) {
this.hiddenClassNamePattern = hiddenClassNamePattern;
this.debug = debug;
if (debug) {
System.out.println("client-local-class-hider: hiding classes that match the regular expression: " + hiddenClassNamePattern);
}
}
/**
* Generates a class with a no-args public constructor.
*
* @param loader
* ignored.
* @param className
* The generated class has this package and name.
* @param classBeingRedefined
* ignored.
* @param protectionDomain
* ignored.
* @param classfileBuffer
* ignored.
* @return bytecode for an empty class whose package and class name are
* determined by the {@code className} parameter.
*/
public byte[] transform(ClassLoader loader, String className,
Class<?> classBeingRedefined, ProtectionDomain protectionDomain,
byte[] classfileBuffer) throws IllegalClassFormatException {
if (!hiddenClassNamePattern.matcher(className).matches()) {
if (debug) {
System.out.println("client-local-class-hider: not hiding " + className);
}
return null;
}
if (debug) {
System.out.println("client-local-class-hider: hiding " + className);
}
return EmtpyClassGenerator.generateEmptyClass(className);
}
}