GridHelloWorldExample.java

Step-By-Step

1. Import GridGain classes.
2. Define Grid Task ID.
3. Add Grid Start and Stop.
4. Add Grid Task Local Deployment.
5. Add Grid Task Execution.

1. Import GridGain classes.

import org.gridgain.grid.*;

2. Define Grid Task ID.

public static final String TASK_TYPE_ID = "GridHelloWordTask";

You can use a constant or use direct String value.

3. Add Grid Start and Stop.

GridFactory.start();
        
try {
    ...
}
finally {
    GridFactory.stop(true);
}

finally clause allows for graceful grid shutdown in case of the exceptions.

4. Add Grid Task Local Deployment.

grid.deployTask(new GridTaskAdapter(TASK_TYPE_ID, GridHelloWorldJob.class.getName()));

Notice that we use an adapter for GridTask that takes task type ID and class name of the root job.

5. Add Grid Task Execution.

grid.execute(TASK_TYPE_ID, "Hello, World!");

Full Source Code

You can copy and paste this source code into your Java editor:

/*
 * LICENSE AGREEMENT
 * 
 * GRIDGAIN 1.0 - GRID COMPUTING FOR JAVA.
 * COPYRIGHT (C) 2005-2007 GRIDGAIN SYSTEMS. ALL RIGHTS RESERVED.
 * 
 * THIS IS FREE SOFTWARE; YOU CAN REDISTRIBUTE IT AND/OR
 * MODIFY IT UNDER THE TERMS OF THE GNU LESSER GENERAL PUBLIC
 * LICENSE AS PUBLISHED BY THE FREE SOFTWARE FOUNDATION; EITHER
 * VERSION 2.1 OF THE LICENSE, OR (AT YOUR OPTION) ANY LATER 
 * VERSION.
 * 
 * THIS LIBRARY 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 LESSER GENERAL PUBLIC LICENSE FOR MORE DETAILS.
 * 
 * YOU SHOULD HAVE RECEIVED A COPY OF THE GNU LESSER GENERAL PUBLIC
 * LICENSE ALONG WITH THIS LIBRARY; IF NOT, WRITE TO THE FREE 
 * SOFTWARE FOUNDATION, INC., 51 FRANKLIN ST, FIFTH FLOOR, BOSTON, MA  
 * 02110-1301 USA
 */


package org.gridgain.examples.helloworld.grid;

import org.apache.log4j.*;
import org.gridgain.grid.*;

/**
 * This example demonstrates a simple use of GridGain grid.
 * <p>
 * String "Hello, World!" is passed as an argument for execution
 * of <tt>HelloWorld</tt> task. As an outcome, two participating
 * nodes will print out a single word from "Hello, World!" string.
 * One node will print out "Hello, " and the other will printout
 * "World!". If there is only one node participating, then it will
 * print out both words.
 * <p>
 * Grid job {@link GridHelloWorldJob} handles actual splitting
 * into sub-jobs, remote execution, and result aggregation
 * (see {@link GridJob}).
 *
 * @author 2005-2007 Copyright (C) GridGain Systems. All Rights Reserved.
 * @version 1.0.0-07022007
 */
public final class GridHelloWorldExample {
    /** Task type ID (value is <tt>GridHelloWorldTask</tt>). */
    public static final String TASK_TYPE_ID = "GridHelloWordTask";

    /** Log4j logger. */
    private static final Logger log = Logger.getLogger(GridHelloWorldExample.class);

    /**
     * Ensure singleton.
     */
    private GridHelloWorldExample() {
        // No-op.
    }
    
    /**
     * Execute <tt>HelloWorld</tt> example on the grid.
     * 
     * @param args Command line arguments, none required.
     * @throws GridException If example execution failed.
     */
    public static void main(String[] args) throws GridException {
        GridFactory.start();
        
        try {
            Grid grid = GridFactory.getGrid();

            // Explicitly deploy task prior to executing.  
            // Since peer class loading is enabled, all 
            // participating nodes will deploy this task
            // from this node automatically.
            grid.deployTask(new GridTaskAdapter(TASK_TYPE_ID, GridHelloWorldJob.class.getName()));
            
            // Execute Hello World task.
            grid.execute(TASK_TYPE_ID, "Hello, World!");
            
            if (log.isInfoEnabled() == true) {
                log.info(">>> Executed \"Hello, World!\" <<<");
            }
        }
        finally {
            GridFactory.stop(true);
        }
    }
}

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