contrib/jwrapper/examples/queue/Queue.java

   1 /*
   2 * This file is part of NIT ( http://www.nitlanguage.org ).
   3 #
   4 # Licensed under the Apache License, Version 2.0 (the "License");
   5 # you may not use this file except in compliance with the License.
   6 # You may obtain a copy of the License at
   7 #
   8 #     http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS,
  12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15 */
  16
  17 import java.util.*;
  18
  19 public class Queue
  20 {
  21     // function pointer
  22     public native void printError( String errorMsg );
  23
  24     // internal list
  25     private LinkedList<String> list;
  26
  27     public Queue()
  28     {
  29         list = new LinkedList<String>();
  30     }
  31
  32     public void push( String element )
  33     {
  34         System.out.print( "From java, pushing " );
  35         System.out.print( element );
  36         System.out.print( "\n" );
  37         list.addLast( element );
  38     }
  39
  40     public String pop() // knows where is native printError
  41     {
  42         String element;
  43
  44         try
  45         {
  46             element = list.removeFirst();
  47         }
  48         catch ( NoSuchElementException e )
  49         {
  50             printError( "From java, empty queue." );
  51             element = null;
  52             throw e;
  53         }
  54
  55         System.out.print( "From java, popping " );
  56         System.out.print( element );
  57         System.out.print( "\n" );
  58
  59         return element;
  60     }
  61 }