fi.jasoft.uidlcompressor.client.ui.UIDLCompressorApplicationConnection.java Source code

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Here is the source code for fi.jasoft.uidlcompressor.client.ui.UIDLCompressorApplicationConnection.java

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/*
 * Copyright 2011 John Ahlroos
 *
 * 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 fi.jasoft.uidlcompressor.client.ui;

import java.util.Date;

import com.google.gwt.http.client.Header;
import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.vaadin.terminal.gwt.client.ApplicationConnection;
import com.vaadin.terminal.gwt.client.VConsole;

/**
 * Client side widget which communicates with the server. Messages from the
 * server are shown as HTML and mouse clicks are sent to the server.
 * 
 * @author John Ahlroos / www.jasoft.fi
 */
public class UIDLCompressorApplicationConnection extends ApplicationConnection {

    /**
     * Decompresses a GZIP+Base64 encoded string into its original form
     * 
     * @param base64String
     *            The input string
     * @return The original string before GZip compression and Base64 encoding
     */
    private static final native String decompressBase64Gzip(String base64String)
    /*-{
     return $wnd.JXG.Util.utf8Decode($wnd.JXG.decompress(base64String));
    }-*/;

    /*
     * (non-Javadoc)
     * 
     * @see
     * com.vaadin.terminal.gwt.client.ApplicationConnection#doAsyncUIDLRequest
     * (java.lang.String, java.lang.String,
     * com.google.gwt.http.client.RequestCallback)
     */
    @Override
    protected void doAsyncUIDLRequest(String uri, String payload, final RequestCallback requestCallback)
            throws RequestException {

        // Wrap the request callback
        RequestCallback wrappedCallback = new RequestCallback() {
            public void onResponseReceived(Request request, final Response response) {

                Response jsonResponse = new Response() {

                    /*
                     * Caching the decoded json string in case getText() is
                     * called several times
                     */
                    private String decodedJson;

                    @Override
                    public String getText() {
                        String base64 = response.getText();
                        if (base64.startsWith("for(")) {
                            // Server is sending json, digress
                            return base64;
                        }

                        if (decodedJson == null) {
                            long start = new Date().getTime();
                            decodedJson = decompressBase64Gzip(base64);
                            long end = new Date().getTime();
                            VConsole.log("Decoding JSON took " + (end - start) + "ms");
                        }

                        return decodedJson;
                    }

                    @Override
                    public String getStatusText() {
                        return response.getStatusText();
                    }

                    @Override
                    public int getStatusCode() {
                        return response.getStatusCode();
                    }

                    @Override
                    public String getHeadersAsString() {
                        return response.getHeadersAsString();
                    }

                    @Override
                    public Header[] getHeaders() {
                        return response.getHeaders();
                    }

                    @Override
                    public String getHeader(String header) {
                        return response.getHeader(header);
                    }
                };

                requestCallback.onResponseReceived(request, jsonResponse);
            }

            public void onError(Request request, Throwable exception) {
                requestCallback.onError(request, exception);
            }
        };

        // TODO Add payload compression here
        super.doAsyncUIDLRequest(uri, payload, wrappedCallback);
    }
}