// IBM_PROLOG_BEGIN_TAG 
// This is an automatically generated prolog. 
//  
// bos720 src/bos/usr/samples/ahafs/samplePrograms/evMon/mon_1event.java 1.1 
//  
// Licensed Materials - Property of IBM 
//  
// Restricted Materials of IBM 
//  
// COPYRIGHT International Business Machines Corp. 2009 
// All Rights Reserved 
//  
// US Government Users Restricted Rights - Use, duplication or 
// disclosure restricted by GSA ADP Schedule Contract with IBM Corp. 
//  
// IBM_PROLOG_END_TAG 
import java.io.*;
public class mon_1event
{
    static String   prog="java mon_1event";
    private static void syntax()
    {
        System.out.println("\nSYNTAX:"+ prog +" <aha-monitor-file> [<key>=<value>] ");
        System.out.println(" where: ");
        System.out.println("  <aha-monitor-file> : Pathname of an AHA file with suffix \".mon\".");
        System.out.println("  The possible keys and their values are:");
        System.out.println("   --------------------------------------------------------------- ");
        System.out.println("        Keys  |       values             |      comments           ");
        System.out.println("   =============================================================== ");
        System.out.println("    CHANGED   | YES (default)            | Monitors state-change.  ");
        System.out.println("   -----------|--------------------------|------------------------ ");
        System.out.println("    THRESH_HI | Positive Integer         | Monitors high threshold.");
        System.out.println("   ----------------------------------------------------------------\n");
        System.out.println("Examples: ");
        System.out.println("   1: "+ prog +" /aha/fs/utilFs.monFactory/var.mon  \"THRESH_HI=95\"");
        System.out.println("   2: "+ prog +" /aha/fs/modFile.monFactory/etc/passwd.mon \"CHANGED=YES\" ");
        System.out.println("   3: "+ prog +" /aha/mem/vmo.monFactory/npskill.mon  ");
    }

    public static void main(String args[])
    {
        if (args.length < 1)
        {
                syntax();
                return ;
        }
                        
        // Create the file object
        File f = new File(args[0]);
        if (! f.exists())  // File does not exist.
        {
            String  parent=f.getParent();
            // See if the parent directory exists.
            if (parent != null)
            {
                // Create the parent directory object.
                File d = new File(parent);
                if (!d.exists()) // If it does not exist.
                {
                    // Create the parent directory.
                    if (! d.mkdirs())
                    {
                        System.out.println("Directory "+ parent +" is not created!");
                        return;
                    }
                }

                // Now create the file.
                try
                {
                    f.createNewFile();
                } catch (Exception e)
                {
                    e.printStackTrace();
                }
            }
        }

        System.out.println("Monitor file name  :"+ args[0]);
        // Get the write string (i.e. interest) to monitor the event.
        String wrStr = "WAIT_TYPE=WAIT_IN_READ";
        if ((args.length >= 2) && (args[1] != null))
        {
            wrStr = wrStr + ";" + args[1];
        }
        else
        {
            wrStr = wrStr + ";" + "CHANGED=YES";
        }
        System.out.println("Write String       :"+wrStr);

        // NOTE: Do not close the writer stream before reading the file using the 
        //       read() or its variant which is required to start monitoring the event.
        //       If the writer stream is closed, the specified interest to monitor
        //       the event is deleted and hence read() will not start monitoring
        //       the event.

        // Open a writer and specify the inetrest.
        BufferedWriter bw = null;
        try
        {
            // Open the writer
            bw = new BufferedWriter(new FileWriter(f));

            // Write the interest
            bw.write(wrStr, 0, wrStr.length());

            // Flush the stream to make sure the interest is written.
            bw.flush();

        } catch (Exception e)
        {
            e.printStackTrace();
        }


        // Open a reader and wait for the occurrence of event using read() or its variant.
        BufferedReader br = null;
        try 
        {
            // Open the reader
            br = new BufferedReader(new FileReader(f));  
            
            System.out.println("Entering read() to wait till the event corresponding to the AHA node "
                               +args[0]+" occurs.");
            System.out.println("Please issue a command from another window to trigger this event.\n");
   
            String rdStr = null;
            // Wait for the event to occur by reading the input stream.
            while ( (rdStr = br.readLine()) != null)
            {
                // Print the content
                System.out.println(rdStr);      
            }
        } catch (Exception e)
        {
            e.printStackTrace();
        }

        // Now, close the reader and writer streams.
        if (br != null)
        {
            try
            {
                br.close();
            } catch (Exception e)
            {
                e.printStackTrace();
            }
        }
        if (bw != null)
        {
            try
            {
                bw.close();
            } catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    } // main
}