fifopagereplacement.java

进程调度和存储管理模拟

package cn.edu.cauc.crab.ossimulate;

import java.util.*;
import javax.swing.*;

/**
 * <p>Title: OS simulate</p>
 * <p>Description: This is my home work.</p>
 * <p>Copyright: Copyleft (c) 2004</p>
 * <p>Company: CAUC</p>
 * @author Crab
 * @version 0.1
 */

/**
 * To simulate first in first out page replacement.
 *
 * @author Crab
 * @version 0.1
 * @see cn.edu.cauc.crab.ossimulate.PageReplacement
 */
public class FIFOPageReplacement extends PageReplacement {

    JTextArea out;

    /**
     * @param memoryBig init the memory page number.
     */
    public FIFOPageReplacement(int memoryBig) {
        super(memoryBig);
    }

    public FIFOPageReplacement(int memoryBig, JTextArea out) {
        super(memoryBig);
        this.out = out;
    }

    void printMemory() {
        if (out == null)
            System.out.print("内存：");
        else
            out.append("内存：");
        Iterator p = memory.iterator();
        while (p.hasNext()) {
            Page page = (Page)p.next();
            if (out == null)
                System.out.print("" + page.number + " ");
            else
                out.append("" + page.number + " ");
        }
        if (out == null)
            System.out.print("\n");
        else
            out.append("\n");
    }

    public void start() {
        while (!pageList.isEmpty()) {
            Page page = (Page)pageList.remove(0);
            if (inMemory(page)) {
                if (out == null)
                    System.out.print("命中：" + page.number + "\n");
                else
                    out.append("命中：" + page.number + "\n");
            } else { // 未命中
                if (memory.size() < memoryBig) {
                    memory.add(page);
                    //out put the memory
                    printMemory();
                } else {
                    memory.remove(0);//out the first
                    memory.add(page);
                    //out put the memory
                    printMemory();
                }
            }
        }
    }

    public static void main(String[] args) {
        PageReplacement pR = new FIFOPageReplacement(3);
        pR.addPage(7);
        pR.addPage(0);
        pR.addPage(1);
        pR.addPage(2);
        pR.addPage(0);
        pR.addPage(3);
        pR.addPage(0);
        pR.addPage(4);
        pR.addPage(2);
        pR.addPage(3);
        pR.addPage(0);
        pR.addPage(3);
        pR.addPage(2);
        pR.addPage(1);
        pR.addPage(2);
        pR.addPage(0);
        pR.addPage(1);
        pR.addPage(7);
        pR.addPage(0);
        pR.addPage(1);
        pR.start();
    }
}