/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.commons.proxy.factory.javassist;
import javassist.CannotCompileException;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtField;
import javassist.LoaderClassPath;
import javassist.NotFoundException;
import org.apache.commons.proxy.ProxyUtils;
import org.apache.commons.proxy.exception.ObjectProviderException;
import java.util.HashSet;
import java.util.Set;
/**
* Some utility methods for dealing with Javassist. This class is not part of the public API!
*
* @author James Carman
* @since 1.0
*/
class JavassistUtils
{
//----------------------------------------------------------------------------------------------------------------------
// Fields
//----------------------------------------------------------------------------------------------------------------------
public static final String DEFAULT_BASE_NAME = "JavassistUtilsGenerated";
private static int classNumber = 0;
private static final ClassPool classPool = new ClassPool();
static
{
classPool.appendClassPath( new LoaderClassPath( ClassLoader.getSystemClassLoader() ) );
}
private static final Set classLoaders = new HashSet();
//----------------------------------------------------------------------------------------------------------------------
// Static Methods
//----------------------------------------------------------------------------------------------------------------------
/**
* Adds a field to a class.
*
* @param fieldType the field's type
* @param fieldName the field name
* @param enclosingClass the class receiving the new field
* @throws CannotCompileException if a compilation problem occurs
*/
public static void addField( Class fieldType, String fieldName, CtClass enclosingClass )
throws CannotCompileException
{
enclosingClass.addField( new CtField( resolve( fieldType ), fieldName, enclosingClass ) );
}
/**
* Finds the {@link CtClass} corresponding to the Java {@link Class} passed in.
*
* @param clazz the Java {@link Class}
* @return the {@link CtClass}
*/
public static CtClass resolve( Class clazz )
{
synchronized( classLoaders )
{
try
{
final ClassLoader loader = clazz.getClassLoader();
if( loader != null && !classLoaders.contains( loader ) )
{
classLoaders.add( loader );
classPool.appendClassPath( new LoaderClassPath( loader ) );
}
return classPool.get( ProxyUtils.getJavaClassName( clazz ) );
}
catch( NotFoundException e )
{
throw new ObjectProviderException(
"Unable to find class " + clazz.getName() + " in default Javassist class pool.", e );
}
}
}
/**
* Adds interfaces to a {@link CtClass}
*
* @param ctClass the {@link CtClass}
* @param proxyClasses the interfaces
*/
public static void addInterfaces( CtClass ctClass, Class[] proxyClasses )
{
for( int i = 0; i < proxyClasses.length; i++ )
{
Class proxyInterface = proxyClasses[i];
ctClass.addInterface( resolve( proxyInterface ) );
}
}
/**
* Creates a new {@link CtClass} derived from the Java {@link Class} using the default base name.
*
* @param superclass the superclass
* @return the new derived {@link CtClass}
*/
public static CtClass createClass( Class superclass )
{
return createClass( DEFAULT_BASE_NAME, superclass );
}
/**
* Creates a new {@link CtClass} derived from the Java {@link Class} using the supplied base name.
*
* @param baseName the base name
* @param superclass the superclass
* @return the new derived {@link CtClass}
*/
public synchronized static CtClass createClass( String baseName, Class superclass )
{
return classPool.makeClass( baseName + "_" + classNumber++, resolve( superclass ) );
}
/**
* Resolves an array of Java {@link Class}es to an array of their corresponding {@link CtClass}es.
*
* @param classes the Java {@link Class}es
* @return the corresponding {@link CtClass}es
*/
public static CtClass[] resolve( Class[] classes )
{
final CtClass[] ctClasses = new CtClass[classes.length];
for( int i = 0; i < ctClasses.length; ++i )
{
ctClasses[i] = resolve( classes[i] );
}
return ctClasses;
}
}