eu.stratosphere.nephele.jobmanager.web.QosStatisticsServlet.java Source code

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Here is the source code for eu.stratosphere.nephele.jobmanager.web.QosStatisticsServlet.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 eu.stratosphere.nephele.jobmanager.web;

import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codehaus.jettison.json.JSONException;
import org.codehaus.jettison.json.JSONObject;

import eu.stratosphere.nephele.jobgraph.JobID;

/**
 * A Servlet that caches and serves qos statistics as JSON.
 * 
 * @author Sascha Wolke
 */
public class QosStatisticsServlet extends HttpServlet {

    private static final long serialVersionUID = 250891613311115346L;

    private static final Log LOG = LogFactory.getLog(QosStatisticsServlet.class);

    private static final ConcurrentHashMap<JobID, JobStatistic> jobStatistics = new ConcurrentHashMap<JobID, JobStatistic>();

    private static JobID lastStartedJob = null;

    private static long INITIAL_REFRESH_INTERVAL = 1000;

    public QosStatisticsServlet() {
    }

    public static abstract class JobStatistic {
        public abstract JobID getJobId();

        public abstract long getCreationTimestamp();

        public abstract JSONObject getJobMetadata() throws JSONException;

        public abstract JSONObject getStatistics(JSONObject jobJson) throws JSONException;

        public abstract JSONObject getStatistics(JSONObject jobJson, long startTimestamp) throws JSONException;

        public abstract long getRefreshInterval();

        public abstract int getMaxEntriesCount();
    }

    public static void putStatistic(JobID jobId, JobStatistic statistics) {
        jobStatistics.put(jobId, statistics);
        lastStartedJob = jobId;
    }

    public static void removeJob(JobID jobId) {
        jobStatistics.remove(jobId);

        if (lastStartedJob == jobId)
            lastStartedJob = null;
    }

    private JobID getLastCreatedJob() {
        if (lastStartedJob != null) {
            return lastStartedJob;
        } else {
            JobID lastCreated = null;
            long ts = -1;

            for (JobStatistic job : jobStatistics.values()) {
                if (job.getCreationTimestamp() > ts) {
                    lastCreated = job.getJobId();
                    ts = job.getCreationTimestamp();
                }
            }

            return lastCreated;
        }
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            resp.setStatus(HttpServletResponse.SC_OK);
            resp.setContentType("application/json");

            JSONObject jobs = new JSONObject();
            JobID job;
            long startTimestamp = -1;

            if (req.getParameter("job") != null && !req.getParameter("job").isEmpty())
                job = JobID.fromHexString(req.getParameter("job"));
            else
                job = getLastCreatedJob();

            if (req.getParameter("startTimestamp") != null && !req.getParameter("startTimestamp").isEmpty())
                startTimestamp = Long.parseLong(req.getParameter("startTimestamp"));

            for (JobID id : jobStatistics.keySet()) {
                JSONObject jobDetails = jobStatistics.get(id).getJobMetadata();

                if (job != null && job.equals(id)) {
                    if (startTimestamp > 0)
                        jobStatistics.get(id).getStatistics(jobDetails, startTimestamp);
                    else
                        jobStatistics.get(id).getStatistics(jobDetails);
                }

                jobs.put(id.toString(), jobDetails);
            }

            JSONObject result = new JSONObject();
            if (job != null && jobStatistics.containsKey(job)) {
                result.put("currentJob", job);
                result.put("refreshInterval", jobStatistics.get(job).getRefreshInterval());
                result.put("maxEntriesCount", jobStatistics.get(job).getMaxEntriesCount());
            } else {
                result.put("refreshInterval", INITIAL_REFRESH_INTERVAL);
                result.put("maxEntriesCount", 0);
            }
            result.put("jobs", jobs);
            result.write(resp.getWriter());

        } catch (JSONException e) {
            LOG.error("JSON Error: " + e.getMessage(), e);
            resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            resp.setContentType("application/json");
            resp.getWriter().println("{ status: \"internal error\", message: \"" + e.getMessage() + "\" }");
        }
    }
}