// Fig. 21.2: StackTest.java
// Program to test java.util.Stack.
import java.util.*;

public class StackTest {

   public StackTest()
   {
      Stack stack = new Stack();  

      // create objects to store in the stack
      Boolean bool = Boolean.TRUE;
      Character character = new Character( '$' );
      Integer integer = new Integer( 34567 );
      String string = "hello";

      // use push method
      stack.push( bool );
      printStack( stack );
      stack.push( character );
      printStack( stack );
      stack.push( integer );
      printStack( stack );
      stack.push( string );
      printStack( stack );

      // remove items from stack
      try {
         Object removedObject = null;

         while ( true ) {
            removedObject = stack.pop(); // use pop method
            System.out.println( removedObject.toString() + " popped" );
            printStack( stack );
         }
      }

      // catch exception if stack is empty when item popped
      catch ( EmptyStackException emptyStackException ) {
         emptyStackException.printStackTrace();
      }
   }
   
   private void printStack( Stack stack )
   {
      if ( stack.isEmpty() )
         System.out.print( "stack is empty" ); // the stack is empty
      
      else {
         System.out.print( "stack contains: " );      
         Enumeration items = stack.elements();
         
         // iterate through the elements
         while ( items.hasMoreElements() )
            System.out.print( items.nextElement() + " " );
      }
      
      System.out.println( "\n" ); // go to the next line
   }
   
   public static void main( String args[] )
   {
      new StackTest();
   }

} // end class StackTest


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