writeoperation.java

高级java2 大学教程(含源码,经典的Java学习教程

// WriteOperation.java
// This application initializes an new Entry object, 
// and deposits this Entry to the JavaSpace.
package com.deitel.advjhtp1.javaspace.write;

// Jini core packages
import net.jini.core.lease.Lease;
import net.jini.core.transaction.TransactionException;

// Jini extension package
import net.jini.space.JavaSpace;

// Java core package
import java.rmi.RemoteException;

// Java extension package
import javax.swing.*;

// Deitel package
import com.deitel.advjhtp1.javaspace.common.*;

public class WriteOperation {

   private JavaSpace space;
   private static final String[] days = { "Monday", "Tuesday",
      "Wednesday", "Thursday", "Friday" };
   private String output = "\n";

   // WriteOperation constructor
   public WriteOperation( String hostname )
   {
      // get the JavaSpace
      String jiniURL = "jini://" +  hostname;
      JavaSpaceFinder findtool = new JavaSpaceFinder( jiniURL );
      space = findtool.getJavaSpace();
   }

   // deposit a new Entry to the JavaSpace
   public void writeEntry( String day )
   {
      // initialize a AttendeeCounter Entry and deposit 
      // Entry object to the JavaSpace
      try {
         AttendeeCounter counter = new AttendeeCounter( day );
         space.write( counter, null, Lease.FOREVER );

         output += "Initialize the Entry: \n";
         output += "   Day: " + day + "\n";
         output += "   Count: 0\n";
      }

      // handle exception network failure 
      catch ( RemoteException exception ) {
         exception.printStackTrace();
      }

      // handle exception invalid transaction
      catch ( TransactionException exception ) {
         exception.printStackTrace();
      }
   }

   // show output
   public void showOutput()
   {
      JTextArea outputArea = new JTextArea();
      outputArea.setText( output );
      JOptionPane.showMessageDialog( null, outputArea, 
         "WriteOperation Output", 
         JOptionPane.INFORMATION_MESSAGE );

      // terminate the program
      System.exit( 0 );
   }

   // method main
   public static void main( String args[] )
   {
      // get the hostname
      if ( args.length != 1 ) {
         System.out.println( 
            "Usage: WriteOperation hostname" );
         System.exit( 1 );
      }
      
      // get the user input day
	  String day = ( String ) JOptionPane.showInputDialog( 
         null, "Select Day", "Day Selection", 
         JOptionPane.QUESTION_MESSAGE, null, days, days[ 0 ] );

      // write an Entry
      WriteOperation write = new WriteOperation( args[ 0 ] );
      write.writeEntry( day );

      write.showOutput();
     
   } // end method main
}

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