com.google.walkaround.wave.server.rpc.HistoryHandler.java Source code

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Here is the source code for com.google.walkaround.wave.server.rpc.HistoryHandler.java

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/*
 * Copyright 2011 Google Inc. All Rights Reserved.
 *
 * 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 com.google.walkaround.wave.server.rpc;

import com.google.inject.Inject;
import com.google.walkaround.slob.server.AccessDeniedException;
import com.google.walkaround.slob.server.ChangeDataSerializer;
import com.google.walkaround.slob.server.SlobStoreSelector;
import com.google.walkaround.slob.server.SlobNotFoundException;
import com.google.walkaround.slob.server.SlobStore;
import com.google.walkaround.slob.server.SlobStore.HistoryResult;
import com.google.walkaround.slob.shared.ChangeData;
import com.google.walkaround.slob.shared.SlobId;
import com.google.walkaround.util.server.servlet.AbstractHandler;
import com.google.walkaround.util.server.servlet.BadRequestException;
import com.google.walkaround.wave.server.ObjectSession;
import com.google.walkaround.wave.server.servlet.ServletUtil;
import com.google.walkaround.wave.shared.SharedConstants.Params;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

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

import javax.annotation.Nullable;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author danilatos@google.com (Daniel Danilatos)
 */
public class HistoryHandler extends AbstractHandler {

    @SuppressWarnings("unused")
    private static final Logger log = Logger.getLogger(HistoryHandler.class.getName());

    @Inject
    SlobStoreSelector storeSelector;
    @Inject
    ObjectSession session;

    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        try {
            inner(req, resp);
        } catch (JSONException e) {
            throw new Error(e);
        } catch (SlobNotFoundException e) {
            throw new BadRequestException("Object not found or access denied", e);
        } catch (AccessDeniedException e) {
            throw new BadRequestException("Object not found or access denied", e);
        }
    }

    private void inner(HttpServletRequest req, HttpServletResponse resp)
            throws IOException, JSONException, SlobNotFoundException, AccessDeniedException {
        long startVersion;
        @Nullable
        Long endVersion;
        try {
            startVersion = Long.parseLong(requireParameter(req, Params.START_REVISION));
            String endVersionString = req.getParameter(Params.END_REVISION);
            if (endVersionString == null) {
                endVersion = null;
            } else {
                endVersion = Long.parseLong(endVersionString);
            }
        } catch (NumberFormatException nfe) {
            throw new BadRequestException(nfe);
        }

        SlobId objectId = session.getObjectId();
        SlobStore store = storeSelector.get(session.getStoreType()).getSlobStore();
        JSONObject result = new JSONObject();
        HistoryResult history = store.loadHistory(objectId, startVersion, endVersion);
        result.put("history", serializeHistory(startVersion, history.getData()));
        result.put("more", history.hasMore());

        resp.setContentType("application/json");
        ServletUtil.writeJsonResult(resp.getWriter(), result.toString());
    }

    static JSONArray serializeHistory(long startVersion, List<ChangeData<String>> entries) throws JSONException {
        JSONArray history = new JSONArray();
        int index = 0;
        for (ChangeData<String> data : entries) {
            history.put(index, ChangeDataSerializer.dataToClientJson(data, startVersion + index + 1));
            index++;
        }
        return history;
    }
}