Nirvana Java Client: Deleting a Channel

This example demonstrates how to delete a Nirvana channel programmatically.

Usage

ndelchan <channel name>  

<Required Arguments> 

<channel name> - Channel name parameter for the channel to delete


Note: -? provides help on environment variables

Application Source Code

See also:

• nSampleApp

/**
 *
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package com.pcbsys.nirvana.apps;
import com.pcbsys.nirvana.client.*;
/**
 * Deletes a nirvana channel
 */
public class deleteChannel extends nSampleApp {
  private static deleteChannel mySelf=null;
  /**
   * This method demonstrates the Nirvana API calls necessary to delete
   * a channel.
   * It is called after all command line arguments have been received and
   * validated
   *
   * @param realmDetails a String[] containing the possible RNAME values
   * @param channelName the channel name to delete
   */
  private void doit(String[] realmDetails, String channelName ) {
    mySelf.constructSession(realmDetails);
    //Deletes the specified channel
    try{
      //Create a channel attributes object
      nChannelAttributes nca = new nChannelAttributes();
      nca.setName( channelName );
      //Delete the channel
      mySession.deleteChannel( nca );
 	  System.out.println("Deleting "+channelName);
    }
    //Handle errors
    catch(nChannelNotFoundException cnfe){
    	
    	try {
			nChannelAttributes[] chanAts = mySession.getChannels(channelName);
			//If the specified channel is actually a folder, ask if the user wishes to delete all channels in this folder.
			if(chanAts.length!=0){
				System.out.println(channelName+" is a folder, do you wish to delete all channels within this folder and it's subfolders? y/n");
				char c =(char) System.in.read();
				if(c=='y'){
					for(nChannelAttributes x:chanAts){
						System.out.println("Deleting "+x.getName());
						mySession.deleteChannel(x);
					}
					
				}
				
			}
			
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
			}
    }
    catch (nSecurityException se) {
      System.out.println("Unsufficient permissions for the requested operation.");
      System.out.println("Please check the ACL settings on the server.");
      se.printStackTrace();
      System.exit(1);
    }
    catch (nSessionNotConnectedException snce) {
      System.out.println("The session object used is not physically connected to the Nirvana realm.");
      System.out.println("Please ensure the realm is up and check your RNAME value.");
      snce.printStackTrace();
      System.exit(1);
    }
    catch (nUnexpectedResponseException ure) {
      System.out.println("The Nirvana REALM has returned an unexpected response.");
      System.out.println("Please ensure the Nirvana REALM and client API used are compatible.");
      ure.printStackTrace();
      System.exit(1);
    }
    catch (nUnknownRemoteRealmException urre) {
      System.out.println("The channel specified resided in a remote realm which could not be found.");
      System.out.println("Please ensure the channel name specified is correct.");
      urre.printStackTrace();
      System.exit(1);
    }
    catch (nRequestTimedOutException rtoe) {
      System.out.println("The requested operation has timed out waiting for a response from the REALM.");
      System.out.println("If this is a very busy REALM ask your administrator to increase the client timeout values.");
      rtoe.printStackTrace();
      System.exit(1);
    }
    catch (nBaseClientException nbce) {
      System.out.println("An error occured while creating the Channel Attributes object.");
      nbce.printStackTrace();
      System.exit(1);
    }
    //Close the session we opened
    try{
      nSessionFactory.close ( mySession );
    }
    catch(Exception ex){}
    //Close any other sessions within this JVM so that we can exit
    nSessionFactory.shutdown ( );
  }
  protected void processArgs(String[] args){
    switch (args.length){
      case 1:
        if (args[0].equals("-?")) {
          Usage();
          UsageEnv();
        }
        System.getProperties().put("CHANNAME",args[0]);
        break;
    }
  }
  public static void main( String[] args ) {
    //Create an instance for this class
    mySelf = new deleteChannel();
    //Process command line arguments
    mySelf.processArgs(args);
    //Process Environment Variables
    nSampleApp.processEnvironmentVariables();
    //Check the channel name specified
    String channelName=null;
    if ( System.getProperty( "CHANNAME" ) != null )
      channelName= System.getProperty( "CHANNAME" ) ;
    else{
      Usage();
      System.exit( 1 );
    }
    //Check the local realm details
    String RNAME=null;
    if ( System.getProperty( "RNAME" ) != null )
      RNAME= System.getProperty( "RNAME" ) ;
    else{
      Usage();
      System.exit( 1 );
    }
    //Process the local REALM RNAME details
    String[] rproperties = new String[4];
    rproperties=parseRealmProperties(RNAME);
    //delete the channel specified
    mySelf.doit(rproperties, channelName);
  }
  /**
   * Prints the usage message for this class
   */
  private static void Usage() {
    System.out.println( "Usage ...\n" );
    System.out.println("ndelchan <channel name>  \n");
    System.out.println(
      "<Required Arguments> \n");
    System.out.println(
      "<channel name> - Channel name parameter for the channel to delete" );
    System.out.println(
      "\n\nNote: -? provides help on environment variables \n");
  }
} // End of deleteChannel Class