carfield.com.hk

BubbleSort.java

2004-03-24T16:00:00Z

package examples.strategy.java;


/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This file is part of the design patterns project at UBC
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ca.ubc.cs.spl.patterns.
 *
 * Contributor(s): 
 */
 
/**
 * Implements the bubblesort sorting strategy for int arrays.
 *
 * @author Jan Hannemann
 * @author Gregor Kiczales
 * @version 1.0, 05/13/02
 * 
 */

public class BubbleSort implements SortingStrategy {

 /**
 * Helper method that exchanges two values in an int array
 * 
 * @param numbers the int array
 * @param pos1 the position of the first element
 * @param pos2 the position of the second element
 */

	private void exchange(int[] numbers, int pos1, int pos2) {
		int tmp = numbers[pos1];
		numbers[pos1] = numbers[pos2];
		numbers[pos2] = tmp;
	}

 /**
 * Sorts an int array
 * 
 * @param numbers the int array to sort
 */

	public void sort(int[] numbers) {
		System.out.println("Sorting by BubbleSort...");		
		for (int end = numbers.length; end > 1; end --) {
			for (int current = 0; current < end - 1; current ++) {
				if (numbers[current] > numbers[current+1]) {
					exchange(numbers, current, current+1);
				}
			}
		}
	}
}

LinearSort.java

2004-03-24T16:00:00Z

package examples.strategy.java;



/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This file is part of the design patterns project at UBC
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ca.ubc.cs.spl.patterns.
 *
 * Contributor(s): 
 */
 
/**
 * Implements the linear sort sorting strategy for int arrays.
 *
 * @author Jan Hannemann
 * @author Gregor Kiczales
 * @version 1.0, 05/13/02
 * 
 */

public class LinearSort implements SortingStrategy{
 
 /**
 * Helper method that exchanges two values in an int array
 * 
 * @param numbers the int array
 * @param pos1 the position of the first element
 * @param pos2 the position of the second element
 */

	private void exchange(int[] numbers, int pos1, int pos2) {
		int tmp = numbers[pos1];
		numbers[pos1] = numbers[pos2];
		numbers[pos2] = tmp;
	}


 /**
 * Sorts an int array
 * 
 * @param numbers the int array to sort
 */

	public void sort(int[] numbers) {
		System.out.println("Sorting by LinearSort...");
		int lowest = 0; 
		
		for (int start = 0; start < numbers.length; start ++) {
			lowest = start;
			
			for (int current = start; current < numbers.length; current ++) {
				if (numbers[current] < numbers[lowest]) {
					lowest = current;
				}
			}
 		exchange(numbers, start, lowest);
		}
	}
}

Main.java

2004-03-24T16:00:00Z

package examples.strategy.java;

/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This file is part of the design patterns project at UBC
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ca.ubc.cs.spl.patterns.
 *
 * Contributor(s): 
 */
 
/**
 * Implements the driver for the strategy design pattern example. 
 *
 * Intent: Define a family of algorithms, encapsulate each one, and make
 * them interchangeable. Strategy lets the algorithm vary independently from 
 * clients that use it.
 *
 * Participatng objects are <code>LinearSort</code> and BubbleSort
 * as Strategies, and <code>Sorter</code> as Context.
 *
 * In this example, an array of 10 numbers is to be sorted. Depending on the
 * number of arguments of the call to <code>Main</code>, linear sort or 
 * bubblesort are used as sorting algorithms. The interface for the strategies
 * is defined in <code>SortingStrategy</code>.
 *
 * This is the Java version.
 *
 * @author Jan Hannemann
 * @author Gregor Kiczales
 * @version 1.0, 05/13/02
 * 
 * @see LinearSort
 * @see BubbleSort
 */
 
public class Main {	
 
 /**
 * Implements the driver for the strategy example. If called with more
 * than zero arguments, bubblesort is used to sort the array of ten
 * numbers; otherwise linear sort. 
 */ 
 
 	public static void main(String[] args)	{
		int[] numbers = {3, 2, 6, 8, 1, 5, 6, 4, 7, 0};
				
		SortingStrategy sort1 = new LinearSort();
		SortingStrategy sort2 = new BubbleSort();
		
		Sorter sorter;
		
		if (args.length == 0) {
			sorter = new Sorter(sort1, numbers);
		} 
		else {
			sorter = new Sorter(sort2, numbers);
		}
	}
}

Sorter.java

2004-03-24T16:00:00Z

package examples.strategy.java;

/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This file is part of the design patterns project at UBC
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ca.ubc.cs.spl.patterns.
 *
 * Contributor(s): 
 */
 
/**
 * Sorts an int array with a provided sorting strategy.
 *
 * @author Jan Hannemann
 * @author Gregor Kiczales
 * @version 1.0, 05/13/02
 * 
 * @see LinearSort
 * @see BubbleSort
 */

public class Sorter { 
 
 /**
 * Returns the content of the int array in a string
 * 
 * @param numbers the int array to display
 * @returns a string with all the ints from the array
 */

	private static String show(int[] numbers) {
		String out = "";
		for (int i=0; i<numbers.length; i++)
		{
			out += (numbers[i] + " ");
		} 
		return out;
	}


 /**
 * Shows the original (unsorted) array, sorts it and shows the new
 * (sorted) array.
 * 
 * @param sort the sorting strategy
 * @param numbers the array of int to sort
 */

	public Sorter(SortingStrategy sort, int[] numbers)	{
		System.out.println("\nPreparing sort...");
		System.out.println("original: "+show(numbers)); 
		sort.sort(numbers);
		System.out.println("sorted: "+show(numbers)); 
	}
}

SortingStrategy.java

2004-03-24T16:00:00Z

files.lst

2004-03-24T16:00:00Z