BeanCopier.java
/*
* Copyright 2003,2004 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 net.sf.cglib.beans;
import java.beans.PropertyDescriptor;
import java.lang.reflect.*;
import java.security.ProtectionDomain;
import net.sf.cglib.core.*;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Type;
import java.util.*;
/**
* @author Chris Nokleberg
*/
abstract public class BeanCopier
{
private static final BeanCopierKey KEY_FACTORY =
(BeanCopierKey)KeyFactory.create(BeanCopierKey.class);
private static final Type CONVERTER =
TypeUtils.parseType("net.sf.cglib.core.Converter");
private static final Type BEAN_COPIER =
TypeUtils.parseType("net.sf.cglib.beans.BeanCopier");
private static final Signature COPY =
new Signature("copy", Type.VOID_TYPE, new Type[]{ Constants.TYPE_OBJECT, Constants.TYPE_OBJECT, CONVERTER });
private static final Signature CONVERT =
TypeUtils.parseSignature("Object convert(Object, Class, Object)");
interface BeanCopierKey {
public Object newInstance(String source, String target, boolean useConverter);
}
public static BeanCopier create(Class source, Class target, boolean useConverter) {
Generator gen = new Generator();
gen.setSource(source);
gen.setTarget(target);
gen.setUseConverter(useConverter);
return gen.create();
}
abstract public void copy(Object from, Object to, Converter converter);
public static class Generator extends AbstractClassGenerator {
private static final Source SOURCE = new Source(BeanCopier.class.getName());
private Class source;
private Class target;
private boolean useConverter;
public Generator() {
super(SOURCE);
}
public void setSource(Class source) {
if(!Modifier.isPublic(source.getModifiers())){
setNamePrefix(source.getName());
}
this.source = source;
}
public void setTarget(Class target) {
if(!Modifier.isPublic(target.getModifiers())){
setNamePrefix(target.getName());
}
this.target = target;
}
public void setUseConverter(boolean useConverter) {
this.useConverter = useConverter;
}
protected ClassLoader getDefaultClassLoader() {
return source.getClassLoader();
}
protected ProtectionDomain getProtectionDomain() {
return ReflectUtils.getProtectionDomain(source);
}
public BeanCopier create() {
Object key = KEY_FACTORY.newInstance(source.getName(), target.getName(), useConverter);
return (BeanCopier)super.create(key);
}
public void generateClass(ClassVisitor v) {
Type sourceType = Type.getType(source);
Type targetType = Type.getType(target);
ClassEmitter ce = new ClassEmitter(v);
ce.begin_class(Constants.V1_8,
Constants.ACC_PUBLIC,
getClassName(),
BEAN_COPIER,
null,
Constants.SOURCE_FILE);
EmitUtils.null_constructor(ce);
CodeEmitter e = ce.begin_method(Constants.ACC_PUBLIC, COPY, null);
PropertyDescriptor[] getters = ReflectUtils.getBeanGetters(source);
PropertyDescriptor[] setters = ReflectUtils.getBeanSetters(target);
Map names = new HashMap();
for (int i = 0; i < getters.length; i++) {
names.put(getters[i].getName(), getters[i]);
}
Local targetLocal = e.make_local();
Local sourceLocal = e.make_local();
if (useConverter) {
e.load_arg(1);
e.checkcast(targetType);
e.store_local(targetLocal);
e.load_arg(0);
e.checkcast(sourceType);
e.store_local(sourceLocal);
} else {
e.load_arg(1);
e.checkcast(targetType);
e.load_arg(0);
e.checkcast(sourceType);
}
for (int i = 0; i < setters.length; i++) {
PropertyDescriptor setter = setters[i];
PropertyDescriptor getter = (PropertyDescriptor)names.get(setter.getName());
if (getter != null) {
MethodInfo read = ReflectUtils.getMethodInfo(getter.getReadMethod());
MethodInfo write = ReflectUtils.getMethodInfo(setter.getWriteMethod());
if (useConverter) {
Type setterType = write.getSignature().getArgumentTypes()[0];
e.load_local(targetLocal);
e.load_arg(2);
e.load_local(sourceLocal);
e.invoke(read);
e.box(read.getSignature().getReturnType());
EmitUtils.load_class(e, setterType);
e.push(write.getSignature().getName());
e.invoke_interface(CONVERTER, CONVERT);
e.unbox_or_zero(setterType);
e.invoke(write);
} else if (compatible(getter, setter)) {
e.dup2();
e.invoke(read);
e.invoke(write);
}
}
}
e.return_value();
e.end_method();
ce.end_class();
}
private static boolean compatible(PropertyDescriptor getter, PropertyDescriptor setter) {
// TODO: allow automatic widening conversions?
return setter.getPropertyType().isAssignableFrom(getter.getPropertyType());
}
protected Object firstInstance(Class type) {
return ReflectUtils.newInstance(type);
}
protected Object nextInstance(Object instance) {
return instance;
}
}
}