nl.strohalm.cyclos.mobile.client.utils.ConnectRequest.java Source code

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Here is the source code for nl.strohalm.cyclos.mobile.client.utils.ConnectRequest.java

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/*
This file is part of Cyclos (www.cyclos.org).
A project of the Social Trade Organisation (www.socialtrade.org).
    
Cyclos is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
    
Cyclos 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 General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with Cyclos; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
    
 */
package nl.strohalm.cyclos.mobile.client.utils;

import java.util.List;

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.http.client.URL;

/**
 * Handles multiple requests to find a valid url.
 */
public abstract class ConnectRequest {

    private List<ConnectAction> requests;

    public ConnectRequest(List<ConnectAction> requests) {
        this.requests = requests;
        execute();
    }

    /**
     * This method is invoked when a valid url has been found or
     * all requests has been done
     * @param url The valid application url, or null if none found 
     */
    protected abstract void onResponseFinished(String url);

    /**
     * Executes the requests and invokes {@link #onResponseFinished(String)}
     */
    private void execute() {
        if (!requests.isEmpty()) {
            final ConnectAction action = requests.remove(0);
            RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, URL.encode(action.getServiceUrl()));
            builder.setTimeoutMillis(15 * 1000); // 15 secs
            try {
                builder.sendRequest(null, new RequestCallback() {
                    public void onError(Request request, Throwable exception) {
                        // Couldn't connect to server (could be timeout, SOP violation, etc.)
                        // Execute next request if available
                        execute();
                    }

                    public void onResponseReceived(Request request, Response response) {
                        if (200 == response.getStatusCode()) {
                            if (action.isAttachment()) {
                                // Return the url in the attachment
                                onResponseFinished(response.getText());
                            } else if (ConnectionHelper.isJSON(response)) {
                                // Return the given valid url
                                onResponseFinished(action.getAppUrl());
                            } else {
                                // Not valid JSON, execute next request if available
                                execute();
                            }
                        } else {
                            // Server error, execute next request if available
                            execute();
                        }
                    }
                });
            } catch (RequestException e) {
                // Couldn't connect to server, execute next request if available 
                execute();
            }
        } else {
            // End of all requests, no valid url has been found
            onResponseFinished(null);
        }
    }
}