lrupagereplacement.java~7~

进程调度和存储管理模拟

package cn.edu.cauc.crab.ossimulate;

import java.util.*;

/**
 * <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
 */

public class LRUPageReplacement extends PageReplacement {

    public LRUPageReplacement(int memoryBig) {
        super(memoryBig);
    }

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

    void deleteLRU() {
        Iterator p = memory.iterator();
        Page lru = (Page)p.next();
        while (p.hasNext()) {
            Page page = (Page)p.next();
            if (page.time < lru.time) {
                lru = page;
            }
        }
        memory.remove(lru);
    }

    public void start() {
        int time = 0;
        while (!pageList.isEmpty()) {
            Page page = (Page)pageList.remove(0);
            if (inMemory(page, time)) {
                System.out.print("命中：" + page.number + "\n");
            } else { // 未命中
                if (memory.size() < memoryBig) {
                    page.time = time;
                    memory.add(page);
                    //out put the memory
                    printMemory();
                } else {
                    deleteLRU();
                    page.time = time;
                    memory.add(page);
                    //out put the memory
                    printMemory();
                }
            }
            time++;
        }
    }
    public static void main(String[] args) {
        PageReplacement pR = new LRUPageReplacement(3);
    }
}