com.goodow.wind.server.rpc.SnapshotHandler.java Source code

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Here is the source code for com.goodow.wind.server.rpc.SnapshotHandler.java

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/*
 * Copyright 2012 Goodow.com
 * 
 * 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.goodow.wind.server.rpc;

import com.goodow.wind.channel.rpc.Constants;
import com.goodow.wind.model.util.Pair;
import com.goodow.wind.server.model.JsonLoader;
import com.goodow.wind.server.model.ObjectId;
import com.goodow.wind.server.model.SessionId;

import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.inject.Inject;
import com.google.walkaround.slob.server.AccessDeniedException;
import com.google.walkaround.slob.server.SlobNotFoundException;
import com.google.walkaround.slob.server.SlobStore.ConnectResult;
import com.google.walkaround.util.server.servlet.AbstractHandler;

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

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

import elemental.json.JsonType;

public class SnapshotHandler extends AbstractHandler {
    private static final Logger log = Logger.getLogger(SnapshotHandler.class.getName());

    @Inject
    private JsonLoader loader;

    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        String key = requireParameter(req, Constants.Params.ID);
        String versionString = optionalParameter(req, Constants.Params.VERSION, null);
        @Nullable
        Long version = versionString == null ? null : Long.parseLong(versionString);

        JsonObject obj;
        try {
            if (version == null) {
                String sid = requireParameter(req, Constants.Params.SESSION_ID);
                String jsonType = optionalParameter(req, Constants.Params.KIND, null);
                Pair<ConnectResult, String> pair = loader.loadOrCreate(key, new SessionId(sid),
                        jsonType == null ? null : JsonType.valueOf(jsonType));
                obj = serialize(pair);
            } else {
                String snapshot = loader.loadStaticAtVersion(new ObjectId(key), version);
                obj = new JsonObject();
                obj.add(Constants.Params.SNAPSHOT, new JsonParser().parse(snapshot));
            }
        } catch (AccessDeniedException e) {
            log.log(Level.SEVERE, "Object not found or access denied", e);
            return;
        } catch (SlobNotFoundException e) {
            log.log(Level.SEVERE, "Object not found or access denied", e);
            return;
        } catch (IOException e) {
            log.log(Level.SEVERE, "Server error loading object", e);
            return;
        }

        resp.setContentType("application/json");
        Util.writeJsonResult(resp.getWriter(), obj.toString());
    }

    private final JsonObject serialize(Pair<ConnectResult, String> pair) {
        JsonObject obj = new JsonObject();
        obj.addProperty(Constants.Params.TOKEN, pair.first.getChannelToken());
        obj.addProperty(Constants.Params.VERSION, pair.first.getVersion());
        obj.add(Constants.Params.SNAPSHOT, new JsonParser().parse(pair.second));
        return obj;
    }
}