VerifierWebWorker.java

/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 *
 *      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.drools.workbench.services.verifier.webworker.client;

import com.google.gwt.core.client.EntryPoint;
import org.drools.workbench.services.verifier.api.client.configuration.RunnerType;
import org.drools.workbench.services.verifier.plugin.client.api.WebWorkerException;
import org.drools.workbench.services.verifier.plugin.client.api.WebWorkerLogMessage;
import org.jboss.errai.enterprise.client.jaxrs.MarshallingWrapper;

public class VerifierWebWorker
        implements EntryPoint {

    private Receiver receiver;

    public void onModuleLoad() {
        setUpListener();

        log( "Creating receiver." );

        this.receiver = new Receiver(
                new Poster(),
                RunnerType.GWT );
    }

    private native void setUpListener()/*-{

        var that = this;

        // Here is the meat. We use self.onmessage to listen to String messages sent from the main application
        // and then redirect them to our GWT code.
        $wnd.receiveFromMainApp = $entry(function (gg) {
            that.@org.drools.workbench.services.verifier.webworker.client.VerifierWebWorker::received(Ljava/lang/String;)(gg)
        });

        self.onmessage = function (event) {
            $wnd.receiveFromMainApp(event.data);
        };

        // GWT uses the window console for logging and errors.
        // If we do not setup our own we get an NPE about missing console, rather than what the actual error is.
        if (!$wnd.window) {
            $wnd.window = {};
        }

        var myConsole = {};

        myConsole.error = function (message) {
            that.@org.drools.workbench.services.verifier.webworker.client.VerifierWebWorker::log(Ljava/lang/String;)(message)
        }

        myConsole.log = function (message) {
            that.@org.drools.workbench.services.verifier.webworker.client.VerifierWebWorker::log(Ljava/lang/String;)(message)
        }

        if (!$wnd.window.console) {
            $wnd.window.console = myConsole;
        }

    }-*/;

    public void log( final String message ) {
        postToMainApp( MarshallingWrapper.toJSON( new WebWorkerLogMessage( message ) ) );
    }

    public void error( final String message ) {
        postToMainApp( MarshallingWrapper.toJSON( new WebWorkerException( message ) ) );
    }

    public void received( final String json ) {


        Object o = null;
        try {
            o = MarshallingWrapper.fromJSON( json );
        } catch ( final Exception e ) {
            error( "Failed to create and object out of the following JSON: " + json );
        }

        if ( o != null ) {
            receiver.received( o );
        }
    }

    /**
     * This is what our GWT codes use to post messages for the main application, we always use JSON objects.
     *
     * The GWT core codes might use postMessage for exceptions for example and these are in plain text.
     * Those are used only for hard, unexpected failures.
     *
     * @param json
     */
    public native void postToMainApp( final String json )/*-{
        postMessage(json);
    }-*/;
}