com.google.gwt.dev.shell.mac.WebKitDispatchAdapter.java Source code

Introduction

Here is the source code for com.google.gwt.dev.shell.mac.WebKitDispatchAdapter.java

Source

/*******************************************************************************
 * 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.gwt.dev.shell.mac;

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.util.Collection;

import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.collections.Predicate;

import com.google.gdt.eclipse.designer.mac.BrowserShellMac;
import com.google.gdt.eclipse.designer.mac.BrowserShellMac.DispatchMethod;
import com.google.gdt.eclipse.designer.mac.BrowserShellMac.DispatchObject;
import com.google.gwt.dev.shell.CompilingClassLoader;
import com.google.gwt.dev.shell.DispatchClassInfo;
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.Jsni;
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 implements DispatchObject {

    protected final CompilingClassLoader classLoader;

    protected final JavaDispatch javaDispatch;

    /**
     * This constructor initializes as the static dispatcher, which handles only
     * static method calls and field references.
     * 
     * @param cl this class's classLoader
     */
    protected WebKitDispatchAdapter(CompilingClassLoader cl) {
        javaDispatch = new JavaDispatchImpl(cl);
        this.classLoader = 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.classLoader = cl;
    }

    public final CompilingClassLoader getClassLoader() {
        return classLoader;
    }

    public long getField(String member) {
        int dispId = getDispId(member);
        if (dispId < 0) {
            return BrowserShellMac.jsUndefined();
        }
        if (!javaDispatch.isField(dispId)) {
            return BrowserShellMac.jsUndefined();
        }
        Field field = javaDispatch.getField(dispId);
        JsValueSaf jsValue = new JsValueSaf();
        JsValueGlue.set(jsValue, classLoader, field.getType(), javaDispatch.getFieldValue(dispId));
        long jsval = jsValue.getJsValue();
        return jsval;
    }

    public Object getWrappedMethod(String member) {
        int dispId = getDispId(member);
        if (dispId < 0) {
            return null;
        }
        if (!javaDispatch.isMethod(dispId)) {
            return null;
        }
        final MethodAdaptor method = javaDispatch.getMethod(dispId);
        AccessibleObject obj = method.getUnderlyingObject();
        DispatchMethod dispMethod = (DispatchMethod) classLoader.getWrapperForObject(obj);
        if (dispMethod == null) {
            dispMethod = new MethodDispatch(classLoader, method);
            classLoader.putWrapperForObject(obj, dispMethod);
        }
        return dispMethod;
    }

    @SuppressWarnings("unchecked")
    public String[] getFields() {
        try {
            DispatchClassInfo classInfo = classLoader.getClassInfoFromClassName(getTarget().getClass().getName());
            Collection<Field> selected = CollectionUtils.select(classInfo.getMembers(), new Predicate() {
                public boolean evaluate(Object object) {
                    return object instanceof Field;
                }
            });
            String[] result = new String[selected.size()];
            int index = 0;
            for (Field field : selected) {
                String jsFieldName = "@" + field.getDeclaringClass().getName() + "::" + field.getName();
                result[index++] = Jsni.WBP_MEMBER + classLoader.getDispId(jsFieldName);
            }
            return result;
        } catch (Throwable e) {
            return new String[0];
        }
    }

    public Object getTarget() {
        return javaDispatch.getTarget();
    }

    public void setField(String member, long value) {
        JsValue jsValue = new JsValueSaf(value);
        int dispId = getDispId(member);
        if (dispId < 0) {
            // TODO (knorton): We could allow expandos, but should we?
            throw new RuntimeException("No such field " + member);
        }
        if (javaDispatch.isMethod(dispId)) {
            throw new RuntimeException("Cannot reassign method " + member);
        }
        Field field = javaDispatch.getField(dispId);
        Object val = JsValueGlue.get(jsValue, classLoader, field.getType(), "setField");
        javaDispatch.setFieldValue(dispId, val);
    }

    @Override
    public String toString() {
        return getTarget().toString();
    }

    private int getDispId(String member) {
        if (member.startsWith(Jsni.WBP_MEMBER)) {
            try {
                return Integer.valueOf(member.substring(Jsni.WBP_MEMBER.length()));
            } catch (Throwable e) {
                return -1;
            }
        } else {
            return classLoader.getDispId(member);
        }
    }

}