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This module contains the Metro runtime code.
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/* 
 *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *  
 *  Copyright (c) 2002-2010 Oracle and/or its affiliates. All rights reserved.
 *  
 *  The contents of this file are subject to the terms of either the GNU
 *  General Public License Version 2 only ("GPL") or the Common Development
 *  and Distribution License("CDDL") (collectively, the "License").  You
 *  may not use this file except in compliance with the License.  You can
 *  obtain a copy of the License at
 *  https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 *  or packager/legal/LICENSE.txt.  See the License for the specific
 *  language governing permissions and limitations under the License.
 *  
 *  When distributing the software, include this License Header Notice in each
 *  file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 *  
 *  GPL Classpath Exception:
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 *  exception as provided by Oracle in the GPL Version 2 section of the License
 *  file that accompanied this code.
 *  
 *  Modifications:
 *  If applicable, add the following below the License Header, with the fields
 *  enclosed by brackets [] replaced by your own identifying information:
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 *  elects to include this software in this distribution under the [CDDL or GPL
 *  Version 2] license."  If you don't indicate a single choice of license, a
 *  recipient has the option to distribute your version of this file under
 *  either the CDDL, the GPL Version 2 or to extend the choice of license to
 *  its licensees as provided above.  However, if you add GPL Version 2 code
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 *  only if the new code is made subject to such option by the copyright
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 */ 

package org.glassfish.gmbal.generic ;

import java.util.Map ;
import java.util.HashMap ;

/** A simple abstraction of a MultiSet, that is, a "set" that can contain
 * more than one copy of the same element.  I am implementing only the
 * bare minimum that is required for now.
 */
public class MultiSet {
     private Map contents = new HashMap() ;

     public void add( E element ) {
	 Integer value = contents.get( element ) ;
	 if (value == null) {
	    value = 0 ;
	 }

	 value += 1 ;
	 contents.put( element, value ) ;
     }

     public void remove( E element ) {
	 Integer value = contents.get( element ) ;
	 if (value == null) {
	     return ;
	 }

	 value -= 1 ;

	 if (value == 0) {
	     contents.remove( element ) ;
	 } else {
	     contents.put( element, value ) ;
	 }
     }

     public boolean contains( E element ) {
	 Integer value = contents.get( element ) ;
	 if (value == null) {
	    value = 0 ;
	 }

	return value > 0 ;
     }

     /** Return the number of unique elements in this MultiSet.
      */
     public int size() {
	 return contents.keySet().size() ;
     }
     
     private static void shouldBeTrue( boolean val, String msg ) {
	 if (!val) 
	     System.out.println( msg ) ;
     }

     private static void shouldBeFalse( boolean val, String msg ) {
	 if (val) 
	     System.out.println( msg ) ;
     }

     public static void main( String[] args ) {
	MultiSet mset = new MultiSet() ;
	String s1 = "first" ;
	String s2 = "second" ;
	
	mset.add( s1 ) ;
	shouldBeTrue( mset.contains( s1 ), "mset does not contain s1 (1)" ) ;

	mset.add( s2 ) ;
	mset.add( s1 ) ;
	mset.remove( s1 ) ;
	shouldBeTrue( mset.contains( s1 ), "mset does not contain s1 (2)" ) ;
	mset.remove( s1 ) ;
	shouldBeFalse( mset.contains( s1 ), "mset still contains s1 (3)" ) ;
	shouldBeTrue( mset.contains( s2 ), "mset does not contain s2 (4)" ) ;
     }
}