---

JobTool.java

Go to the documentation of this file.

package net.threebit.utils.sosc;

/*
        Copyright 2003 Shawn Deleurme
        Copyright 2003 Kevin O'Donnell

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; either version 2 of the License, or
        (at your option) any later version.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program; if not, write to the Free Software
        Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

import java.io.*;
import java.sql.*;
import java.util.*;
import javax.servlet.http.*;
import java.lang.reflect.*;

public class JobTool {

        private static JobTool jobTool = null;

        private static boolean ready = false;

        private DbTool db = null;

        public final String JOB_TABLE = "jobToolJobs";

        public final String JOB_ARGUMENTS = "jobToolArguments";

        public final String JOB_LOG = "jobToolLog";

        private ArrayList jobs = new ArrayList();

        public JobTool (DbTool dbTool) {
                this.db = dbTool;
        }

        public synchronized static JobTool initialize(DbTool dbTool) throws Exception {
                ready = true;
                jobTool = new JobTool(dbTool);
                return getInstance();
        }

        public synchronized static JobTool getInstance() throws Exception {
                if (! ready) { throw new IllegalStateException("JobTool not ready.  Call initialize() first."); }
                return jobTool;
        }

        public void addJob (String queue, String description, String type, String className, Map args) throws Exception {

                // The only supported type at this time.
                if (queue == null || queue.length() == 0) { throw new Exception("Queue '" + queue + "' is not valid."); }
                if (! type.equals("java")) { throw new Exception("Type '" + type + "' is not supported."); }

                // Safer to assign an empty map than check for nulls throughout the method
                if (args == null) { args = new HashMap(); }

                synchronized (this) {
                        // Insert a new job into the database.
                        db.update(
                                " insert into " + JOB_TABLE +
                                "   (queue, description, type, class) \n" +
                                " values (\n" +
                                "   " + db.quote(queue) + ", \n" +
                                "   " + db.quote(description) + ", \n" +
                                "   " + db.quote(type) + ", \n" +
                                "   " + db.quote(className) + " \n" +
                                " ); "
                        );

                        // This is syncrhonized and therefore safe
                        int newId = db.getInt("select max(id) from " + JOB_TABLE + ";");
                        System.out.println("Job " + newId + " created");

                        for (Iterator i = args.keySet().iterator(); i.hasNext(); ) {
                                String key = (String) i.next();
                                String val = (String) args.get(key);
                                db.update(
                                        " insert into " + JOB_ARGUMENTS +
                                        "   (job,k,v) \n" +
                                        " values (\n" +
                                        "   " + newId + ", \n" +
                                        "   " + db.quote(key) + ", \n" +
                                        "   " + db.quote(val) + " \n" +
                                        " ); "
                                );
                        }
                        db.commit();

                        // Log the creation
                        log(newId,"Job queued");
                }
        }

        public Job runJob (String queue, Map args2) throws Exception {

                int jobId;
                Map row = null;
                Map args1 = null;
                Job job = null;

                synchronized (this) {

                        // Get the next job to run.
                        String s = db.getString("select min(id) from " + JOB_TABLE + " where state = 0 and queue = " + db.quote(queue) + ";");
                        if (s == null || s.equals("null")) {
                                System.out.println("No jobs for queue: " + queue);
                                return null;
                        }
                        else {
                                jobId = Integer.valueOf(s).intValue();
                        }

                        // Get the job data
                        ResultSet r = db.query(" select * from " + JOB_TABLE + " where id = " + jobId);
                        row = db.toMap(r);
                        r.close();

                        // Get the job arguments (if any)
                        r = db.query(" select * from " + JOB_ARGUMENTS + " where job = " + jobId);
                        args1 = new HashMap();
                        while (r.next()) {
                                args1.put( r.getString("k"), r.getString("v"));
                        }
                        r.close();

                        // Mark the job as "running" now then go unsynchronized
                        db.update(" update " + JOB_TABLE + " set updated = getdate(), state = 1 where id = " + jobId);
                        db.commit();

                        // Find the class and it's contructor
                        log(jobId,"initializing");
                        String className = (String) row.get("class");
                        Class classy = Class.forName(className);
                        Constructor constructor = classy.getConstructor(new Class[] { int.class, String.class, Map.class, Map.class });
                        job = (Job) constructor.newInstance(new Object[] { new Integer(jobId), row.get("description"), args1, args2 });

                        // Keep a link to the running job
                        jobs.add(job);
                }

                // Run the job
                log(jobId,"executing");
                job.execute();

                // END OF JOB RUN

                synchronized (this) {
                        jobs.remove(job);
                        // Mark the job as completed
                        db.update(" update " + JOB_TABLE + " set updated = getdate(), state = 2 where id = " + jobId);
                        log(jobId,"finished");
                        db.commit();
                }

                // return real job object when done.
                return null;

        }

        public void log (int jobId, String text) throws Exception {
                synchronized (this) {
                        db.update(" insert into " + JOB_LOG + " (job,text) values (" + jobId + "," + db.quote(text) + ");");
                }
        }

}

---