org.waveprotocol.box.webclient.client.SnapshotFetcher.java Source code

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Here is the source code for org.waveprotocol.box.webclient.client.SnapshotFetcher.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.waveprotocol.box.webclient.client;

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 org.waveprotocol.box.common.comms.jso.WaveViewSnapshotJsoImpl;
import org.waveprotocol.box.webclient.common.SnapshotSerializer;
import org.waveprotocol.box.webclient.common.communication.callback.SimpleCallback;
import org.waveprotocol.wave.client.debug.logger.DomLogger;
import org.waveprotocol.wave.common.logging.LoggerBundle;
import org.waveprotocol.wave.communication.gwt.JsonMessage;
import org.waveprotocol.wave.communication.json.JsonException;
import org.waveprotocol.wave.model.id.InvalidIdException;
import org.waveprotocol.wave.model.id.WaveId;
import org.waveprotocol.wave.model.operation.OperationException;
import org.waveprotocol.wave.model.wave.InvalidParticipantAddress;
import org.waveprotocol.wave.model.wave.data.DocumentFactory;
import org.waveprotocol.wave.model.wave.data.WaveViewData;
import org.waveprotocol.wave.model.waveref.WaveRef;
import org.waveprotocol.wave.util.escapers.GwtWaverefEncoder;

/**
 * Helper class to fetch wavelet snapshots using the snapshot fetch service.
 *
 * @author josephg@gmail.com (Joseph Gentle)
 */
public final class SnapshotFetcher {
    private static final LoggerBundle LOG = new DomLogger("SnapshotFetcher");
    private static final String FETCH_URL_BASE = "/fetch";

    private SnapshotFetcher() {
    }

    private static String getUrl(WaveRef waveRef) {
        String pathSegment = GwtWaverefEncoder.encodeToUriPathSegment(waveRef);
        return FETCH_URL_BASE + "/" + pathSegment;
    }

    /**
     * Fetches a wave view snapshot from the static fetch servlet.
     *
     * @param waveId The wave to fetch
     * @param callback A callback through which the fetched wave will be returned.
     */
    public static void fetchWave(WaveId waveId, final SimpleCallback<WaveViewData, Throwable> callback,
            final DocumentFactory<?> docFactory) {
        String url = getUrl(WaveRef.of(waveId));
        LOG.trace().log("Fetching wavelet ", waveId.toString(), " at ", url);

        RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, url);
        requestBuilder.setCallback(new RequestCallback() {
            @Override
            public void onResponseReceived(Request request, Response response) {
                LOG.trace().log("Snapshot response recieved: ", response.getText());
                // Pull the snapshot out of the response object and return it using
                // the provided callback function.
                if (response.getStatusCode() != Response.SC_OK) {
                    callback.onFailure(new RequestException("Got back status code " + response.getStatusCode()));
                } else if (!response.getHeader("Content-Type").startsWith("application/json")) {
                    callback.onFailure(new RuntimeException("Fetch service did not return json"));
                } else {
                    WaveViewData waveView;
                    try {
                        WaveViewSnapshotJsoImpl snapshot = JsonMessage.parse(response.getText());
                        waveView = SnapshotSerializer.deserializeWave(snapshot, docFactory);
                    } catch (OperationException e) {
                        callback.onFailure(e);
                        return;
                    } catch (InvalidParticipantAddress e) {
                        callback.onFailure(e);
                        return;
                    } catch (InvalidIdException e) {
                        callback.onFailure(e);
                        return;
                    } catch (JsonException e) {
                        callback.onFailure(e);
                        return;
                    }
                    callback.onSuccess(waveView);
                }
            }

            @Override
            public void onError(Request request, Throwable exception) {
                LOG.error().log("Snapshot error: ", exception);
                callback.onFailure(exception);
            }
        });

        try {
            requestBuilder.send();
        } catch (RequestException e) {
            callback.onFailure(e);
        }
    }
}