memalloc.java

用JAVA实现的模拟内存管理程序

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.LinkedList;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextArea;

/*
 * Created on 2004-5-19
 *
 * To change the template for this generated file go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */

/**
 * @author 李秋军(010200)
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
public class MemAlloc extends JPanel implements Runnable
{
	LinkedList memList = new LinkedList();
	MemAreaInfo memAreaInfo;
	JTextArea text = new JTextArea(20, 12);
	JButton bt = new JButton("首次适应算法演示");
	private boolean controlFlag = false;
	private boolean stopFile = false;
	PrintStream ps;

	public MemAlloc()
	{
		init();
		bt.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent arg0)
			{
				if (!controlFlag)
				{
					text.setText("");
					memList.clear();
					stopFile = true;
					init();
					controlFlag = true;
					repaint();
				}
			}
		});

		this.add(text); //将文本区加入面板
		this.add(bt); //将按钮加入面板

	}

	//	初始化链表
	void init()
	{
		memAreaInfo = new MemAreaInfo(0, 640, false, -1);
		memList.add(memAreaInfo);
		if (stopFile)
		{
			try
			{
				ps =
					new PrintStream(
						new BufferedOutputStream(
							new FileOutputStream("firstMem.txt")));
			} catch (IOException e)
			{
				System.out.println(e);
			}
			ps.println("                       首次适应算法\r\n");
			print("内存初始状态");
		}
	}

	//	分配内存
	public boolean alloc(int memSize, int id)
	{
		for (int i = 0; i < memList.size(); i++)
		{
			memAreaInfo = (MemAreaInfo) memList.get(i);
			if (!memAreaInfo.isAlloc() && memAreaInfo.getLength() >= memSize)
			{

				if (memAreaInfo.getLength() == memSize)
				{
					memAreaInfo.setId(id);
					memAreaInfo.setAlloc(true);
				} else
				{
					MemAreaInfo newMemArea =
						new MemAreaInfo(
							memAreaInfo.getStartAddr(),
							memSize,
							true,
							id);
					memAreaInfo.setStartAddr(
						memAreaInfo.getStartAddr() + memSize);
					memAreaInfo.setLength(memAreaInfo.getLength() - memSize);
					memList.add(i, newMemArea);
				}
				break;
			}
		}
		if (stopFile)
		{
			print("作业" + id + "分配" + memSize + "M内存后");
		}
		repaint();
		return true;
	}

	//	释入内存
	public boolean dealloc(int id)
	{
		int a = 0, b = 0;
		for (int i = 0; i < memList.size(); i++)
		{
			memAreaInfo = (MemAreaInfo) memList.get(i);
			if (memAreaInfo.getId() == id)
			{
				memAreaInfo.setAlloc(false);
				memAreaInfo.setId(-1);
				if (i > 0 && !((MemAreaInfo) memList.get(i - 1)).isAlloc())
				{
					((MemAreaInfo) memList.get(i - 1)).setLength(
						((MemAreaInfo) memList.get(i - 1)).getLength()
							+ memAreaInfo.getLength());
					a = i;
				}

				if (i < memList.size() - 1
					&& !((MemAreaInfo) memList.get(i + 1)).isAlloc())
				{
					if (a > 0)
					{
						((MemAreaInfo) memList.get(i - 1)).setLength(
							((MemAreaInfo) memList.get(i - 1)).getLength()
								+ ((MemAreaInfo) memList.get(i + 1)).getLength());
						b = i + 1;
					} else if (a == 0)
					{
						memAreaInfo.setLength(
							memAreaInfo.getLength()
								+ ((MemAreaInfo) memList.get(i + 1)).getLength());
						b = i + 1;
					}
				}
				break;
			}
		}
		if (b > 0)
		{
			memList.remove(b);
			if (a > 0)
			{
				memList.remove(a);
				a = 0;
			}
		}
		if (a > 0)
		{
			memList.remove(a);
		}
		if (stopFile)
		{
			print("作业" + id + "释放内存后");
		}
		repaint();
		return true;
	}

	public void paintComponent(Graphics g)
	{

		g.setColor(new Color(123, 193, 193));
		g.fillRect(0, 0, 1024, 768);
		g.setColor(Color.magenta);
		g.drawString("作业情况:", 230, 90);
		text.setBackground(new Color(123, 180, 123));
		text.setLocation(220, 100);
		bt.setLocation(120, 20);

		for (int i = 0; i < memList.size(); i++)
		{
			memAreaInfo = (MemAreaInfo) memList.get(i);

			if (memAreaInfo.isAlloc())
			{
				g.setColor(Color.blue);
				g.fillRect(
					50,
					(memAreaInfo.getStartAddr() + 100) * 2 / 3,
					120,
					memAreaInfo.getLength() * 2 / 3);
			} else
			{
				g.setColor(Color.white);
				g.fillRect(
					50,
					(memAreaInfo.getStartAddr() + 100) * 2 / 3,
					120,
					memAreaInfo.getLength() * 2 / 3);
			}

			g.setColor(Color.magenta);
			g.drawString(
				String.valueOf(memAreaInfo.getStartAddr()) + "M",
				180,
				(memAreaInfo.getStartAddr() + 110) * 2 / 3);
		}
		g.drawString("640M", 180, (640 + 110) * 2 / 3);

		g.setColor(Color.blue);
		g.fillRect(50, 510, 60, 20);
		g.drawString("已分配内存", 120, 523);
		g.setColor(Color.white);
		g.fillRect(50, 540, 60, 20);
		g.drawString("空闲内存", 120, 553);
	}

	//线程的run()函数
	public void run()
	{
		while (true)
		{

			try
			{
				Thread.sleep(100);
			} catch (InterruptedException e)
			{
				System.out.println(e);
			}
			if (controlFlag)
			{
				repaint();
				try
				{
					alloc(130, 1);
					text.append("作业1申请130K\n");
					Thread.sleep(1000);
					alloc(60, 2);
					text.append("作业2申请60K\n");
					Thread.sleep(1000);
					alloc(100, 3);
					text.append("作业3申请100k\n");
					Thread.sleep(1000);
					dealloc(2);
					text.append("作业2释放60K\n");
					Thread.sleep(1000);
					alloc(200, 4);
					text.append("作业4申请200K\n");
					Thread.sleep(1000);
					dealloc(3);
					text.append("作业3释放100K\n");
					Thread.sleep(1000);
					dealloc(1);
					text.append("作业1释放130K\n");
					Thread.sleep(1000);
					alloc(140, 5);
					text.append("作业5申请140K\n");
					Thread.sleep(1000);
					alloc(60, 6);
					text.append("作业6申请60K\n");
					Thread.sleep(1000);
					alloc(50, 7);
					text.append("作业7申请50K\n");
					Thread.sleep(1000);
					dealloc(6);
					text.append("作业6释放60K\n");
					if (stopFile)
					{
						ps.close();
						stopFile = false;
					}
					text.append("\n详细内存分区信息在\n文件(firstMem.txt)中");

				} catch (InterruptedException e)
				{
					System.out.println(e.toString());
				}
				controlFlag = false;
			}
		}

	}
	void print(String s)
	{
		ps.print("\r\n-----------------" + s + "-----------------\r\n");
		ps.println(" 起始地址          长度\t\t目前状态\r\n");
		for (int i = 0; i < memList.size(); i++)
		{
			MemAreaInfo m = (MemAreaInfo) memList.get(i);
			ps.println(m);
		}
		ps.println("\r\n");
	}
}