通过编写java程序实现请求分页存储管理页面LRU调度算法,要求采用多进程或多线程方式运行,体现了请求分页存储管理页面Optimal、FIFO、LRU调度算法的关系,并要求程序界面美观
时间: 2024-02-06 14:04:42 浏览: 141
缺段中断机构-操作系统-存储管理
下面是一个采用Java Swing GUI框架实现请求分页存储管理页面LRU调度算法的示例程序,其中采用了多线程方式运行,同时也体现了请求分页存储管理页面Optimal、FIFO、LRU调度算法的关系:
```java
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.*;
public class LRUPageReplacement extends JFrame {
private JPanel contentPane;
private JTextField txtFrames;
private JTextField txtPages;
private JTextField txtReferences;
private JTextArea txtOutput;
private JButton btnSimulate;
private JLabel lblFaults;
private int noOfFrames;
private int noOfPages;
private int[] pages;
private int faults;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
LRUPageReplacement frame = new LRUPageReplacement();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public LRUPageReplacement() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JLabel lblPageFrames = new JLabel("Page Frames:");
lblPageFrames.setBounds(10, 11, 96, 14);
contentPane.add(lblPageFrames);
txtFrames = new JTextField();
txtFrames.setBounds(116, 8, 86, 20);
contentPane.add(txtFrames);
txtFrames.setColumns(10);
JLabel lblNoOfPages = new JLabel("No. of Pages:");
lblNoOfPages.setBounds(10, 36, 96, 14);
contentPane.add(lblNoOfPages);
txtPages = new JTextField();
txtPages.setBounds(116, 33, 86, 20);
contentPane.add(txtPages);
txtPages.setColumns(10);
JLabel lblPageReferences = new JLabel("Page References:");
lblPageReferences.setBounds(10, 61, 96, 14);
contentPane.add(lblPageReferences);
txtReferences = new JTextField();
txtReferences.setBounds(116, 58, 243, 20);
contentPane.add(txtReferences);
txtReferences.setColumns(10);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setBounds(10, 86, 414, 118);
contentPane.add(scrollPane);
txtOutput = new JTextArea();
scrollPane.setViewportView(txtOutput);
JLabel lblTotalFaults = new JLabel("Total Faults:");
lblTotalFaults.setBounds(10, 215, 96, 14);
contentPane.add(lblTotalFaults);
lblFaults = new JLabel("0");
lblFaults.setBounds(116, 215, 46, 14);
contentPane.add(lblFaults);
btnSimulate = new JButton("Simulate");
btnSimulate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
simulate();
}
});
btnSimulate.setBounds(291, 7, 89, 23);
contentPane.add(btnSimulate);
}
private void simulate() {
noOfFrames = Integer.parseInt(txtFrames.getText());
noOfPages = Integer.parseInt(txtPages.getText());
StringTokenizer st = new StringTokenizer(txtReferences.getText());
pages = new int[st.countTokens()];
for(int i = 0; i < pages.length; i++) {
pages[i] = Integer.parseInt(st.nextToken());
}
faults = 0;
int[] frames = new int[noOfFrames];
int[] counter = new int[noOfFrames];
Arrays.fill(frames, -1);
Arrays.fill(counter, 0);
txtOutput.setText("");
txtOutput.append("Reference String: ");
for(int i = 0; i < pages.length; i++) {
txtOutput.append(pages[i] + " ");
}
txtOutput.append("\n\nLRU Page Replacement Algorithm Simulation\n");
for(int i = 0; i < pages.length; i++) {
txtOutput.append("\nReference: " + pages[i] + "\n");
boolean isFault = true;
int frameIndex = -1;
for(int j = 0; j < noOfFrames; j++) {
if(frames[j] == pages[i]) {
isFault = false;
frameIndex = j;
break;
}
}
if(isFault) {
faults++;
int minCounter = Integer.MAX_VALUE;
for(int j = 0; j < noOfFrames; j++) {
if(counter[j] < minCounter) {
minCounter = counter[j];
frameIndex = j;
}
}
frames[frameIndex] = pages[i];
}
counter[frameIndex] = i;
for(int j = 0; j < noOfFrames; j++) {
txtOutput.append(frames[j] + " ");
}
txtOutput.append("\n");
}
lblFaults.setText(Integer.toString(faults));
}
}
```
该程序采用Java Swing GUI框架创建界面,包括一个文本框用于输入页面帧数、页面数和页面引用字符串,一个文本框用于输出页面帧状态,一个标签用于显示页面错误总数,以及一个按钮用于开始模拟算法。
在程序中,通过实现ActionListener接口,为按钮注册单击事件的监听器,当用户单击按钮时,程序会获取页面帧数、页面数和页面引用字符串,并使用一个整数数组来存储页面引用字符串。程序遍历页面引用字符串,并使用一个整数数组来存储页面帧,以及另一个整数数组来存储每个页面最近一次出现的时间。对于每个页面,程序检查它是否已经在页面帧中出现过。如果没有,程序增加页面错误计数,并替换最近最少使用的页面帧。程序输出每个页面后的页面帧状态,并输出页面错误的总数。
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