eu.stratosphere.pact.client.web.PactJobJSONServlet.java Source code

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Here is the source code for eu.stratosphere.pact.client.web.PactJobJSONServlet.java

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/***********************************************************************************************************************
 *
 * Copyright (C) 2010 by the Stratosphere project (http://stratosphere.eu)
 *
 * 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 eu.stratosphere.pact.client.web;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;

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 eu.stratosphere.pact.client.nephele.api.Client;
import eu.stratosphere.pact.client.nephele.api.PactProgram;

public class PactJobJSONServlet extends HttpServlet {

    /** Serial UID for serialization interoperability. */
    private static final long serialVersionUID = 558077298726449201L;

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

    // ------------------------------------------------------------------------

    private static final String JOB_PARAM_NAME = "job";

    // ------------------------------------------------------------------------

    private final File jobStoreDirectory; // the directory in which the jobs are stored

    public PactJobJSONServlet(File jobStoreDirectory) {
        this.jobStoreDirectory = jobStoreDirectory;
    }

    /*
     * (non-Javadoc)
     * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest,
     * javax.servlet.http.HttpServletResponse)
     */
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("application/json");

        String jobName = req.getParameter(JOB_PARAM_NAME);
        if (jobName == null) {
            LOG.warn("Received request without job parameter name.");
            resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            return;
        }

        // check, if the jar exists
        File jarFile = new File(jobStoreDirectory, jobName);
        if (!jarFile.exists()) {
            LOG.warn("Received request for non-existing jar file.");
            resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            return;
        }

        // create the pact plan
        PactProgram pactProgram;
        try {
            pactProgram = new PactProgram(jarFile, new String[0]);
        } catch (Throwable t) {
            LOG.info("Instantiating the PactProgram for '" + jarFile.getName() + "' failed.", t);
            resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            resp.getWriter().print(t.getMessage());
            return;
        }

        String jsonPlan = null;
        String programDescription = null;

        try {
            jsonPlan = Client.getPreviewAsJSON(pactProgram);
        } catch (Throwable t) {
            LOG.error("Failed to create json dump of pact program.", t);
        }

        try {
            programDescription = pactProgram.getDescription();
        } catch (Throwable t) {
            LOG.error("Failed to create description of pact program.", t);
        }

        if (jsonPlan == null && programDescription == null) {
            resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            return;
        } else {
            resp.setStatus(HttpServletResponse.SC_OK);
            PrintWriter wrt = resp.getWriter();
            wrt.print("{ \"jobname\": \"");
            wrt.print(jobName);
            if (jsonPlan != null) {
                wrt.print("\", \"plan\": ");
                wrt.println(jsonPlan);
            }
            if (programDescription != null) {
                wrt.print(", \"description\": \"");
                wrt.print(escapeString(programDescription));
            }

            wrt.print("\"");
            wrt.println("}");
        }
    }

    protected String escapeString(String str) {
        int len = str.length();
        char[] s = str.toCharArray();
        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < len; i += 1) {
            char c = s[i];
            if ((c == '\\') || (c == '"') || (c == '/')) {
                sb.append('\\');
                sb.append(c);
            } else if (c == '\b')
                sb.append("\\b");
            else if (c == '\t')
                sb.append("\\t");
            else if (c == '\n')
                sb.append("<br>");
            else if (c == '\f')
                sb.append("\\f");
            else if (c == '\r')
                sb.append("\\r");
            else if (c == '>')
                sb.append("&gt;");
            else if (c == '<')
                sb.append("&lt;");
            else {
                if (c < ' ') {
                    // Unreadable throw away
                } else {
                    sb.append(c);
                }
            }
        }

        return sb.toString();
    }
}