tapestry-framework/src/org/apache/tapestry/enhance/javassist/EnhancedClass.java

//  Copyright 2004 The Apache Software Foundation
//
// 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.apache.tapestry.enhance.javassist;

import javassist.ClassPool;
import javassist.CtClass;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.tapestry.enhance.BaseEnhancedClass;
import org.apache.tapestry.enhance.EnhancedClassLoader;
import org.apache.tapestry.enhance.IEnhancer;
import org.apache.tapestry.enhance.MethodSignature;

import java.util.HashSet;
import java.util.Set;

/**
 *  Represents a class to be enhanced using Javassist. 
 *
 *  @author Mindbridge
 *  @version $Id$
 *  @since 3.0
 */
public class EnhancedClass extends BaseEnhancedClass
{
    private static final Log LOG = LogFactory.getLog(EnhancedClass.class);

    private String _className;
    private Class _parentClass;
    private EnhancedClassFactory _classFactory;

    private ClassFabricator _classFabricator = null;

    private Set _methods = new HashSet();

    public EnhancedClass(String className, Class parentClass, EnhancedClassFactory classFactory)
    {
        _className = className;
        _parentClass = parentClass;
        _classFactory = classFactory;
    }

    /**
     * @see org.apache.tapestry.enhance.IEnhancedClass#getClassName()
     */
    public String getClassName()
    {
        return _className;
    }

    public CtClass getObjectType(String type)
    {
        return _classFactory.getObjectType(type);
    }

    public ClassFabricator getClassFabricator()
    {
        if (_classFabricator == null)
        {
            CtClass jaParentClass = getObjectType(_parentClass.getName());
            ClassPool classPool = _classFactory.getClassPool();
            _classFabricator = new ClassFabricator(_className, jaParentClass, classPool);
        }
        return _classFabricator;
    }

    /**
     * @see org.apache.tapestry.enhance.IEnhancedClass#createProperty(java.lang.String, java.lang.String)
     */
    public void createProperty(String propertyName, String propertyType)
    {
        createProperty(propertyName, propertyType, null, false);
    }

    /**
     * @see org.apache.tapestry.enhance.IEnhancedClass#createProperty(java.lang.String, java.lang.String, java.lang.String, boolean)
     */
    public void createProperty(
            String propertyName,
            String propertyType,
            String readMethodName,
            boolean persistent)
    {
        IEnhancer enhancer =
                new CreatePropertyEnhancer(
                        propertyName,
                        getObjectType(propertyType),
                        readMethodName,
                        persistent);
        addEnhancer(enhancer);
    }

    /**
     * @see org.apache.tapestry.enhance.IEnhancedClass#createAutoParameter(java.lang.String, java.lang.String, java.lang.String, java.lang.String)
     */
    public void createAutoParameter(
            String propertyName,
            String parameterName,
            String typeClassName,
            String readMethodName)
    {
        IEnhancer enhancer =
                new CreateAutoParameterEnhancer(
                        this,
                        propertyName,
                        parameterName,
                        getObjectType(typeClassName),
                        readMethodName);
        addEnhancer(enhancer);
    }

    /**
     * @see org.apache.tapestry.enhance.IEnhancedClass#createEnhancedSubclass()
     */
    public Class createEnhancedSubclass()
    {
        performEnhancement();

        ClassFabricator cf = getClassFabricator();
        cf.commit();

        String enhancedClassName = getClassName();
        byte[] enhancedClassBytes = cf.getByteCode();

        EnhancedClassLoader loader = _classFactory.getEnhancedClassLoader();
        return loader.defineClass(
                enhancedClassName,
                enhancedClassBytes,
                _parentClass.getProtectionDomain());
    }

    public void addInterface(Class type)
    {
        getClassFabricator().addInterface(type);
    }

    public void addMethod(int modifiers, MethodSignature signature, String body)
    {
        getClassFabricator().addMethod(modifiers, signature, body);
        _methods.add(signature);
    }

    public void addField(String name, Class type)
    {
        getClassFabricator().createField(getClassFabricator().getCtClass(type), name);
    }

    public void addConstructor(Class[] parameterTypes, Class[] exceptions, String body)
    {
        getClassFabricator().addConstructor(parameterTypes, exceptions, body);
    }

    public boolean containsMethod(MethodSignature signature)
    {
        return _methods.contains(signature);
    }
}