MvsJobOutput.java

/*
 * %Z%%W% %I%
 *
 * =========================================================================
 * Licensed Materials - Property of IBM
 * "Restricted Materials of IBM"
 * (C) Copyright IBM Corp. 2011. All Rights Reserved
 * 
 * DISCLAIMER: 
 * The following [enclosed] code is sample code created by IBM 
 * Corporation.  This sample code is not part of any standard IBM product 
 * and is provided to you solely for the purpose of assisting you in the 
 * development of your applications.  The code is provided 'AS IS', 
 * without warranty of any kind.  IBM shall not be liable for any damages 
 * arising out of your use of the sample code, even if they have been 
 * advised of the possibility of such damages.
 * =========================================================================
 */
package com.ibm.jzos.sample;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Iterator;
import java.util.Properties;
import java.util.StringTokenizer;

import com.ibm.jzos.Exec;
import com.ibm.jzos.RcException;
import com.ibm.jzos.ZUtil;

/**
 * Sample program which reads all sysout data for a MvsJob (jobname and jobid),
 * and writes the output to a specified Writer.
 * 
 * The class relies on the sample REXX script "jobOutput", spawned as a child process
 * via the {@link com.ibm.jzos.Exec} class.
 * 
 * @since 2.1.0
 */
public class MvsJobOutput {
    
    public static final String JOB_STATUS_CMD = "jobStatus";
	public static final String JOB_OUTPUT_CMD = "jobOutput";
	
	/**
	 * A sample main method that writes sysout output for
	 * a job to System.out (STDOUT).
	 * 
	 * The first argument is the jobname, and the second argument
	 * is the jobid (JOBnnnnn).
	 */
	public static void main(String[] args) throws IOException {
	    
		if (args.length < 2 ) {
		    throw new IllegalArgumentException("Missing arguments: jobname jobid");
		}
		
		MvsJob mvsJob = new MvsJob(args[0], args[1]);
		
		// print out the status of the job
		// this will throw an exception if there is no such job
		System.out.println("JOB " + mvsJob + " " + getStatus(mvsJob));

		BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
		writeJobOutput(mvsJob, writer);
		writer.close();
	}
	
    /**
     * Returns the job status using the TSO "status" command, which
     * is invoked via the "jobStatus" REXX USS script.
     * 
     * @return String the TSO "STATUS" command status
     * @throws IOException if there was an error communicating with the child REXX script process
     */
    public static String getStatus(MvsJob job) throws IOException {
        Exec exec = new Exec(getStatusCommand(job), getEnvironment());
        exec.run();

        String line = exec.readLine();
        if (line == null) throw new IOException("No output from jobStatus child process");
        
        // close the stream which is connected
        // to the stdin input of the external process
        BufferedWriter wdr = exec.getStdinWriter();
        wdr.close();

        // slurp other output
        while (exec.readLine() != null) {};
        
        int rc = exec.getReturnCode();
        if (rc != 0) {
            throw new RcException("REXX 'jobStatus' process failed: " + line, rc);
        }
        
        StringTokenizer tok = new StringTokenizer(line);
        if (tok.countTokens() < 3 ) {
            throw new IOException("Invalid output from jobStatus child process: " + line);
        }
        
        String next = tok.nextToken();
        
        // skip over message id
        if (next.startsWith("IKJ")) {
            next = tok.nextToken();
        }
        
        if (!next.equalsIgnoreCase("JOB")) {
            throw new IOException("Invalid output from jobStatus child process: " + line);
        }
        
        // skip jobname(jobid)
        tok.nextToken();
        String answer = "";
        
        // concat remaining words
        while (tok.hasMoreTokens()) {
            answer += tok.nextToken();
            
            if (tok.hasMoreTokens()) {
                answer += " ";
            }
        }

        return answer;
    }
    
    /**
     * Returns the command to be executed via Runtime.exec().
     * This is the REXX script 'jobStatus' followed by the jobname and jobid.
     * By default, this script needs to be present in the current PATH.
     * However, if the System variable jzos.script.path is defined, it will
     * be used to prefix 'jobStatus'.
     */
    protected static String getStatusCommand(MvsJob job) {
        String cmdPath = System.getProperty("jzos.script.path", "");
        if (cmdPath.length() > 0 && !cmdPath.endsWith("/")) {
            cmdPath = cmdPath + "/";
        }
        
        cmdPath = cmdPath + JOB_STATUS_CMD
                  + " "
                  + job.getJobname()
                  + " ";
        
        if (job.getJobid() != null) {
            cmdPath = cmdPath + job.getJobid();
        }
        
        return cmdPath;
    }
	
	/**
	 * Writes all of the output for a given job to a writer.
	 * Note: this method flushes the writer, but does not close it.
	 * It is the caller's responsibility to close the writer.
	 */
	public static void writeJobOutput(MvsJob mvsJob, Writer writer) throws IOException {
		Exec exec = new Exec(getJobOutputCommand(mvsJob), getEnvironment());
		exec.run();
		
		try {
			String line;
			while ((line = exec.readLine()) != null) {
				writer.write(line);
				writer.write('\n');
			};
			
			writer.flush();
		}
		finally {
			int rc = exec.getReturnCode();
			if (rc != 0) {
				throw new RcException("REXX 'jobOutput' process failed", rc);
			}
		}
	}
	
	/**
	 * Returns the command to be executed via Runtime.exec().
	 * This is the REXX script 'jobOutput'.
	 * By default, this script needs to be present in the current PATH.
	 * However, if the System variable jzos.script.path is defined, it will be
	 * used to prefix 'jobOutput'.
	 */
	protected static String getJobOutputCommand(MvsJob mvsJob) {
		String cmdPath = System.getProperty("jzos.script.path", "");
		if (cmdPath.length() > 0 && !cmdPath.endsWith("/")) {
			cmdPath = cmdPath + "/";
		}
		
		return cmdPath + JOB_OUTPUT_CMD 
				+ " "
				+ mvsJob.getJobname()
				+ " "
				+ mvsJob.getJobid();
	}

	/**
	 * Returns the environment to use for the child process.
	 * This is the current environment with _BPX_SHAREAS and _BPX_SPAWN_SCRIPT
	 * set to "YES", so that the child process will execute in the same
	 * address space.
	 */
	protected static String[] getEnvironment() {
		Properties p = ZUtil.getEnvironment();
		p.put("_BPX_SHAREAS", "YES");
		p.put("_BPX_SPAWN_SCRIPT", "YES");
		
		String[] environ = new String[p.size()];
		int i = 0;
	    
		for (Iterator<Object> iter = p.keySet().iterator(); iter.hasNext();) {
	    	String key = (String)iter.next();
	    	environ[i++] = key + "=" + p.getProperty(key);
	    }
		
	    return environ;
	}
}