org.cruxframework.crux.plugin.gadget.rebind.rpc.CruxGadgetProxyCreator.java Source code

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Here is the source code for org.cruxframework.crux.plugin.gadget.rebind.rpc.CruxGadgetProxyCreator.java

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/*
 * Copyright 2011 cruxframework.org.
 * 
 * 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.cruxframework.crux.plugin.gadget.rebind.rpc;

import java.io.PrintWriter;

import org.cruxframework.crux.core.client.utils.EscapeUtils;
import org.cruxframework.crux.core.rebind.rpc.CruxProxyCreator;
import org.cruxframework.crux.plugin.gadget.util.HangoutUtils;

import com.google.gwt.core.ext.GeneratorContext;
import com.google.gwt.core.ext.RebindMode;
import com.google.gwt.core.ext.RebindResult;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.typeinfo.JClassType;
import com.google.gwt.gadgets.client.gwtrpc.GadgetsGwtRpc;
import com.google.gwt.user.client.rpc.ServiceDefTarget;
import com.google.gwt.user.rebind.ClassSourceFileComposerFactory;
import com.google.gwt.user.rebind.SourceWriter;

/**
 * This class overrides the Crux Proxy Creator to add a wrapper class around the original generated class. 
 * 
 * <p>
 * The wrapper redirects the original request through a proxy, as described on:<br>
 *  http://code.google.com/p/gwt-google-apis/wiki/GadgetsFAQ#How_can_I_get_GWT_RPC_to_work_in_a_Gadget?
 * </p>
 * 
 * 
 * @author Thiago da Rosa de Bustamante 
 *
 */
public class CruxGadgetProxyCreator extends CruxProxyCreator {
    private static final String WRAPPER_SUFFIX = "_GadgetWrapper";
    private TreeLogger logger;

    /**
     * @param type
     */
    public CruxGadgetProxyCreator(JClassType type) {
        super(type);
    }

    /**
     * @see com.google.gwt.user.rebind.rpc.ProxyCreator#create(com.google.gwt.core.ext.TreeLogger, com.google.gwt.core.ext.GeneratorContext)
     */
    @Override
    public RebindResult create(TreeLogger logger, GeneratorContext context) throws UnableToCompleteException {
        this.logger = logger;
        RebindResult result = super.create(logger, context);
        String cruxServiceTypeName = result.getResultTypeName();

        return createGadgetWrapper(context, cruxServiceTypeName);
    }

    /**
     * @param logger
     * @param context
     * @param cruxServiceTypeName
     * @return
     * @throws UnableToCompleteException 
     */
    private RebindResult createGadgetWrapper(GeneratorContext context, String cruxServiceTypeName)
            throws UnableToCompleteException {
        SourceWriter srcWriter = getSourceWriter(logger, context, cruxServiceTypeName);

        String gadgetWrapperName = getGadgetProxyQualifiedName();
        if (srcWriter == null) {
            return new RebindResult(RebindMode.USE_EXISTING, gadgetWrapperName);
        }

        generateGadgetProxyContructor(srcWriter);

        srcWriter.commit(logger);

        return new RebindResult(RebindMode.USE_ALL_NEW_WITH_NO_CACHING, gadgetWrapperName);
    }

    /**
     * @param srcWriter
     */
    private void generateGadgetProxyContructor(SourceWriter srcWriter) {
        srcWriter.println("public " + getGadgetProxySimpleName() + "() {");
        srcWriter.indent();

        srcWriter.println("super();");

        if (HangoutUtils.isHangoutGadget()) {
            srcWriter.println("GadgetsGwtRpc.redirectThroughProxy((ServiceDefTarget) this, "
                    + EscapeUtils.quote(HangoutUtils.getDeployURL()) + ");");
        } else {
            srcWriter.println("GadgetsGwtRpc.redirectThroughProxy((ServiceDefTarget) this);");
        }

        srcWriter.outdent();
        srcWriter.println("}");
    }

    /**
     * @param logger
     * @param ctx
     * @param cruxServiceTypeName 
     * @return
     */
    private SourceWriter getSourceWriter(TreeLogger logger, GeneratorContext ctx, String cruxServiceTypeName) {
        String name[] = getPackageAndClassName(getGadgetProxyQualifiedName());
        String packageName = name[0];
        String className = name[1];
        PrintWriter printWriter = ctx.tryCreate(logger, packageName, className);
        if (printWriter == null) {
            return null;
        }

        ClassSourceFileComposerFactory composerFactory = new ClassSourceFileComposerFactory(packageName, className);

        composerFactory.addImport(GadgetsGwtRpc.class.getCanonicalName());
        composerFactory.addImport(ServiceDefTarget.class.getCanonicalName());

        composerFactory.setSuperclass(cruxServiceTypeName);

        return composerFactory.createSourceWriter(ctx, printWriter);
    }

    /**
     * @return
     */
    private String getGadgetProxyQualifiedName() {
        return serviceIntf.getQualifiedSourceName() + WRAPPER_SUFFIX;
    }

    /**
     * @return
     */
    private String getGadgetProxySimpleName() {
        return serviceIntf.getSimpleSourceName() + WRAPPER_SUFFIX;
    }
}