/*
* Copyright 2008 Google Inc.
*
* 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 com.google.gwt.dev.shell;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
/**
* Class for wrapping Java things for JavaScript.
*/
public class JavaDispatchImpl implements JavaDispatch {
private final CompilingClassLoader classLoader;
private final Object target;
/**
* This constructor initializes a dispatcher for handling static members.
*
* @param ccl class loader to use for dispatching member access
*/
public JavaDispatchImpl(CompilingClassLoader ccl) {
classLoader = ccl;
target = null;
}
/**
* This constructor initializes a dispatcher around a particular instance.
*
* @param ccl class loader to use for dispatching member access
* @param target the instance object to use for dispatching member accesses
*
* @throws NullPointerException if target is null
*/
public JavaDispatchImpl(CompilingClassLoader ccl, Object target) {
if (target == null) {
throw new NullPointerException("target cannot be null");
}
classLoader = ccl;
this.target = target;
}
/**
* @param dispId the unique number of a field
* @return the field
*/
public Field getField(int dispId) {
Member member = getMember(dispId);
if (member instanceof SyntheticClassMember) {
try {
Field f = SyntheticClassMember.class.getDeclaredField("clazz");
assert f != null;
return f;
} catch (SecurityException e) {
} catch (NoSuchFieldException e) {
}
assert false : "Should never get here";
}
return (Field) member;
}
/**
* @param dispId the unique number of a field
* @return true the value of the field
* @throws IllegalArgumentException
*/
public Object getFieldValue(int dispId) {
Member member = getMember(dispId);
if (member instanceof SyntheticClassMember) {
return member.getDeclaringClass();
}
Field field = (Field) member;
try {
return field.get(target);
} catch (IllegalAccessException e) {
// should never, ever happen
e.printStackTrace();
throw new RuntimeException(e);
}
}
/**
* @param dispId the unique number of a method
* @return the method
*/
public MethodAdaptor getMethod(int dispId) {
Member m = getMember(dispId);
if (m instanceof Method) {
return new MethodAdaptor((Method) m);
} else if (m instanceof Constructor) {
return new MethodAdaptor((Constructor<?>) m);
} else {
throw new RuntimeException();
}
}
public Object getTarget() {
return target;
}
/**
* @param dispId the unique number of a method or field
* @return true if the dispId represents a field
*/
public boolean isField(int dispId) {
if (dispId < 0) {
return false;
}
Member member = getMember(dispId);
return member instanceof Field || member instanceof SyntheticClassMember;
}
/**
* @param dispId the unique number of a method or field
* @return true if the dispId represents a method
*/
public boolean isMethod(int dispId) {
if (dispId < 0) {
return false;
}
Member m = getMember(dispId);
return (m instanceof Method) || (m instanceof Constructor);
}
/**
* @param dispId the unique number of a field
* @param value the value to assign to the field
* @throws IllegalArgumentException
*/
public void setFieldValue(int dispId, Object value) {
Field field = (Field) getMember(dispId);
try {
field.set(target, value);
} catch (IllegalAccessException e) {
// should never, ever happen
e.printStackTrace();
throw new RuntimeException(e);
}
}
/**
* @param dispId the unique number of a method or field
* @return the member
*/
protected Member getMember(int dispId) {
DispatchClassInfo clsInfo = classLoader.getClassInfoByDispId(dispId);
return clsInfo.getMember(dispId);
}
}