Embedding Pig Scripts in Java Applications

You are familiar with running pig scripts via the command line. Now what if you intend to run Apache Pig as part of your Java applications?

Pig Modes

There are two modes as shown in http://pig.apache.org/docs/r0.7.0/setup.html#Run+Modes

PigServer

This is the main class for embedding Apache Pig as part of your java applications.


import org.apache.pig.PigServer;

=================
 PigServer pigServer = null;
String mode = "local";
 String pigScriptName = null;

Map<String,String> params = null;

List<String> paramFiles = null;

        try {
            pigServer = new PigServer(mode);
            pigServer.setBatchOn();
            pigServer.debugOn();
            InputStream is = getClass().getClassLoader().getResourceAsStream(pigScriptName);
            if(params != null){
                pigServer.registerScript(is, params);
            } else if(paramFiles != null){
                pigServer.registerScript(is, paramFiles);
            } else {
                pigServer.registerScript(is);
            }
            pigServer.executeBatch();
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            if(pigServer != null){
                pigServer.shutdown();
            }
        }
==========================
Note: the variable mode can be "local" or "mapreduce".

PigServer can take two additional parameters while registering your pig script.

• Params: this is a key/value map passed that can be referenced in your pigscript as $key.
• ParamFiles: takes in filenames that contain the parameters.

You can register the script with the PigServer without providing any params.

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All the best!

Reference: http://everythingbigdata.blogspot.com/2012/07/apache-pig-tips.html