com.calclab.emite.base.util.Platform.java Source code

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Here is the source code for com.calclab.emite.base.util.Platform.java

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/*
 * ((e)) emite: A pure Google Web Toolkit XMPP library
 * Copyright (c) 2008-2011 The Emite development team
 * 
 * This file is part of Emite.
 *
 * Emite is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * Emite is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with Emite.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.calclab.emite.base.util;

import java.util.List;
import java.util.logging.Logger;

import javax.annotation.Nullable;

import com.calclab.emite.base.xml.XMLBuilder;
import com.calclab.emite.base.xml.XMLPacket;
import com.calclab.emite.core.AsyncResult;
import com.google.common.collect.Lists;
import com.google.common.net.HttpHeaders;
import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;

/**
 * Methods with a special GWT implementation.
 * 
 * TODO: create Java versions of these methods.
 */
public final class Platform {

    private static final Logger logger = Logger.getLogger(Platform.class.getName());

    private static final List<Request> requests;

    static {
        requests = Lists.newArrayList();

        // On close it cancels all the pending requests except the "terminate" request
        Window.addWindowClosingHandler(new Window.ClosingHandler() {
            @Override
            public void onWindowClosing(@Nullable final Window.ClosingEvent event) {
                int i = requests.size() - 2;
                logger.finer("Cancelling " + (i + 1) + " pending requests.");
                for (; i >= 0; i--) {
                    requests.get(i).cancel();
                }
                logger.finer("Cancelled all requests.");
            }
        });
    }

    /**
     * Schedule an action to run in the future.
     * 
     * @param msecs delay before running the action (in milliseconds)
     * @param action the action to run
     */
    public static final void schedule(final int msecs, final ScheduledAction action) {
        new Timer() {
            @Override
            public void run() {
                action.run();
            }
        }.schedule(msecs);
    }

    /**
     * Send a BOSH HTTP request to a server.
     * 
     * @param httpBase the base URL to send the request
     * @param request the request contents
     * @param callback a callback to process the response
     */
    public static final void sendXML(final String httpBase, final XMLPacket request,
            final AsyncResult<XMLPacket> callback) {
        final RequestBuilder builder = new RequestBuilder(RequestBuilder.POST, httpBase);
        builder.setHeader(HttpHeaders.CONTENT_TYPE, "text/xml; charset=utf-8");
        //builder.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache");
        //builder.setHeader(HttpHeaders.PRAGMA, "no-cache");
        // TODO : Hard coded timeout to 6s, but we should set it to the wait + a delta
        // builder.setTimeoutMillis(6000);
        try {
            final Request req = builder.sendRequest(request.toString(), new RequestCallback() {
                @Override
                public void onResponseReceived(@Nullable final Request req, @Nullable final Response res) {
                    requests.remove(req);
                    if (res.getStatusCode() != Response.SC_OK) {
                        callback.onError(new RequestException(
                                "Invalid status " + res.getStatusCode() + ": " + res.getStatusText()));
                        return;
                    }

                    final XMLPacket response = XMLBuilder.fromXML(res.getText());
                    if (response == null || !"body".equals(response.getTagName())) {
                        callback.onError(new RequestException("Bad response: " + res.getText()));
                        return;
                    }

                    callback.onSuccess(response);
                }

                @Override
                public void onError(@Nullable final Request req, @Nullable final Throwable throwable) {
                    logger.severe("GWT CONNECTOR ERROR: " + throwable.getMessage());
                    requests.remove(req);
                    callback.onError(throwable);
                }
            });
            requests.add(req);
        } catch (final RequestException e) {
            callback.onError(e);
        } catch (final Exception e) {
            logger.severe("Some GWT connector exception: " + e.getMessage());
            callback.onError(e);
        }
    }

    private Platform() {
    }

}