tests/test_jvm/Queue.java

   1 package test_jvm;
   2
   3 import java.util.*;
   4
   5 class Queue
   6 {
   7     // function pointer
   8     public native void printError( String errorMsg );
   9
  10     // internal list
  11     private LinkedList<String> list;
  12
  13     public Queue()
  14     {
  15         list = new LinkedList<String>();
  16     }
  17
  18     public void push( String element )
  19     {
  20         System.out.print( "From java, pushing " );
  21         System.out.print( element );
  22         System.out.print( "\n" );
  23         list.addLast( element );
  24     }
  25
  26     public String pop() // knows where is native printError
  27     {
  28         String element;
  29
  30         try
  31         {
  32             element = list.removeFirst();
  33         }
  34         catch ( NoSuchElementException e )
  35         {
  36             printError( "From java, empty queue." );
  37             element = null;
  38             throw e;
  39         }
  40
  41         System.out.print( "From java, popping " );
  42         System.out.print( element );
  43         System.out.print( "\n" );
  44
  45         return element;
  46     }
  47 }
  48