/*******************************************************************************
* Copyright 2011 Google Inc. All Rights Reserved.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* 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.gdt.eclipse.designer.webkit.jsni;
import java.lang.ref.WeakReference;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import com.google.gdt.eclipse.designer.webkit.jsni.LowLevelWebKit.DispatchMethod;
import com.google.gdt.eclipse.designer.webkit.jsni.LowLevelWebKit.DispatchObject;
import com.google.gwt.dev.shell.CompilingClassLoader;
import com.google.gwt.dev.shell.JavaDispatch;
import com.google.gwt.dev.shell.JavaDispatchImpl;
import com.google.gwt.dev.shell.JsValue;
import com.google.gwt.dev.shell.JsValueGlue;
import com.google.gwt.dev.shell.MethodAdaptor;
/**
* Wraps an arbitrary Java Object as a Dispatch component. The class was motivated by the need to
* expose Java objects into JavaScript.
*
* An instance of this class with no target is used to globally access all static methods or fields.
*/
class WebKitDispatchAdapter<H extends Number> implements DispatchObject<H> {
WeakReference<CompilingClassLoader> classLoaderRef;
JavaDispatch javaDispatch;
/**
* This constructor initializes as the static dispatcher, which handles only static method calls
* and field references.
*
* @param cl
* this class's classLoader
*/
WebKitDispatchAdapter(CompilingClassLoader cl) {
javaDispatch = new JavaDispatchImpl(cl);
this.classLoaderRef = new WeakReference<CompilingClassLoader>(cl);
}
/**
* This constructor initializes a dispatcher, around a particular instance.
*
* @param cl
* this class's classLoader
* @param target
* the object being wrapped as an IDispatch
*/
WebKitDispatchAdapter(CompilingClassLoader cl, Object target) {
javaDispatch = new JavaDispatchImpl(cl, target);
this.classLoaderRef = new WeakReference<CompilingClassLoader>(cl);
}
public H getField(H jsContext, String name) {
LowLevelWebKit.pushJsContext(jsContext);
CompilingClassLoader classLoader = classLoaderRef.get();
if (classLoader == null) {
throw new RuntimeException("Invalid class loader.");
}
try {
int dispId = getDispId(name);
if (dispId < 0) {
return LowLevelWebKit.getJsUndefined(jsContext);
}
if (javaDispatch.isField(dispId)) {
Field field = javaDispatch.getField(dispId);
JsValueWebKit<H> jsValue = new JsValueWebKit<H>();
JsValueGlue.set(jsValue, classLoader, field.getType(), javaDispatch.getFieldValue(dispId));
H jsval = jsValue.getJsValue();
// Native code will eat an extra ref.
LowLevelWebKit.gcProtect(jsContext, jsval);
return jsval;
} else {
MethodAdaptor method = javaDispatch.getMethod(dispId);
AccessibleObject obj = method.getUnderlyingObject();
DispatchMethod<?> dispMethod = (DispatchMethod<?>) classLoader.getWrapperForObject(obj);
if (dispMethod == null) {
dispMethod = new MethodDispatch<H>(classLoader, method);
classLoader.putWrapperForObject(obj, dispMethod);
}
// Native code eats the same ref it gave us.
return LowLevelWebKit.wrapDispatchMethod(jsContext, method.toString(), dispMethod);
}
} finally {
LowLevelWebKit.popJsContext(jsContext);
}
}
public Object getTarget() {
return javaDispatch.getTarget();
}
public void setField(H jsContext, String name, H value) {
CompilingClassLoader classLoader = classLoaderRef.get();
if (classLoader == null) {
throw new RuntimeException("Invalid class loader.");
}
LowLevelWebKit.pushJsContext(jsContext);
try {
JsValue jsValue = new JsValueWebKit<H>(value);
int dispId = getDispId(name);
if (dispId < 0) {
// TODO (knorton): We could allow expandos, but should we?
throw new RuntimeException("No such field " + name);
}
if (javaDispatch.isMethod(dispId)) {
throw new RuntimeException("Cannot reassign method " + name);
}
Field field = javaDispatch.getField(dispId);
Object val = JsValueGlue.get(jsValue, classLoader, field.getType(), "setField");
javaDispatch.setFieldValue(dispId, val);
} finally {
LowLevelWebKit.popJsContext(jsContext);
}
}
private int getDispId(String member) {
try {
return Integer.valueOf(member);
} catch (Throwable e) {
CompilingClassLoader classLoader = classLoaderRef.get();
if (classLoader == null) {
throw new RuntimeException("Invalid class loader.");
}
return classLoader.getDispId(member);
}
}
@Override
public String toString() {
return getTarget().toString();
}
}