Merge pull request #34 from JaneZhou91/master

the fourth homework

group19/1294642551/src/LRU/LRUPageFrame.java

@@ -0,0 +1,142 @@
+package LRU;
+
+/**
+ * 使用双向链表实现LRU算法
+ * @author 12946
+ *
+ */
+
+public class LRUPageFrame {
+
+	private static class Node {
+
+		Node prev = null;
+		Node next = null;
+		int pageNum;
+
+		Node(Object data) {
+			if(data != null){
+				this.pageNum = (Integer)data;
+			}
+		}
+	}
+
+	private int capacity;//链表总元素个数
+	private int currentSize;//链表当前元素个数
+	private Node first;// 链表头
+	private Node last;// 链表尾
+
+
+	public LRUPageFrame(int capacity) {
+
+		first = new Node(null);//栈底，元素最先放入的地方
+		last = new Node(null);//栈顶
+
+		this.currentSize = 0;
+		this.capacity = capacity;
+
+	}
+
+	/**
+	 * 获取缓存中对象
+	 * 
+	 * @param key
+	 * @return
+	 */
+	public void access(int pageNum) {
+		Node newNode = new Node(pageNum);
+
+		if(currentSize == capacity){
+			Node tempNode = null;
+			if(getIndex(pageNum) == -1){//不包含
+				tempNode = first.next;
+			}else{//包含
+				tempNode = getNode(pageNum);
+			}
+			(tempNode.prev).next = tempNode.next;
+			(tempNode.next).prev = tempNode.prev;
+
+
+			newNode.next = last;
+			newNode.prev = last.prev;
+			last.prev = newNode;
+			newNode.prev.next = newNode;
+		}
+
+		if(currentSize < capacity){
+			Node point = first;
+			for(int i = 0; i < currentSize; i++){
+				point = point.next;
+			}
+			point.next = newNode;
+			newNode.prev = point;
+
+			newNode.next = last;
+			last.prev = newNode;
+
+			currentSize += 1;
+		}
+
+
+	}
+
+	public Node getNode(int data){
+
+		Node point = first.next;
+		for(int i = 0; i < capacity; i++){
+			if(point.pageNum == data){
+				return point;
+			}
+			point = point.next;
+		}
+
+		return null;
+
+	}
+
+
+	public int getIndex(int data){
+		Node point = first.next;
+		for(int i = 0; i < capacity; i++){
+			if(point.pageNum == data){
+				return i;
+			}
+			point = point.next;
+		}
+
+		return -1;
+	}
+
+//  原toString	
+//	public String toString(){
+//		StringBuilder buffer = new StringBuilder();
+//		Node node = first;
+//		while(node != null){
+//			buffer.append(node.pageNum);			
+//			
+//			node = node.next;
+//			if(node != null){
+//				buffer.append(",");
+//			}
+//		}
+//		return buffer.toString();
+//	}
+
+	public String toString(){
+		StringBuilder sb = new StringBuilder();
+		Node point = last.prev;
+		while(point != first){
+			sb.append(point.pageNum);
+			if(point.prev != first){
+				sb.append(",");
+			}
+			point = point.prev;
+		}
+
+		return sb.toString();
+
+	}
+
+
+
+}

group19/1294642551/src/jvm/loader/ClassFileLoader.java

@@ -0,0 +1,140 @@
+package jvm.loader;
+
+import java.io.BufferedInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.StringUtils;
+
+
+import jvm.clz.ClassFile;
+
+
+
+public class ClassFileLoader {
+
+	private List<String> clzPaths = new ArrayList<String>();
+
+	public byte[] readBinaryCode(String className) {
+
+		className = className.replace('.', File.separatorChar) + ".class";
+
+		for(String path : clzPaths){
+			String clzFileName = path + File.separatorChar + className;
+			byte[] codes = loadClassFile(clzFileName);
+			if(codes != null){
+				return codes;
+			}
+		}
+
+		return null;
+
+	}
+
+	private byte[] loadClassFile(String clzFileName) {
+
+		try {
+			InputStream input = new FileInputStream(new File(clzFileName));
+			return IOUtils.toByteArray(input);
+		} catch (FileNotFoundException e) {
+			e.printStackTrace();
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+
+		return null;
+	}
+
+
+
+	public void addClassPath(String path) {
+		if(this.clzPaths.contains(path)){
+			return;
+		}
+
+		this.clzPaths.add(path);
+
+	}
+
+
+
+	public String getClassPath(){
+		return StringUtils.join(this.clzPaths,";");
+	}
+
+	public ClassFile loadClass(String className) {
+//		byte[] codes = this.readBinaryCode(className);
+//		ClassFileParser parser = new ClassFileParser();
+//		return parser.parse(codes);
+		return null;
+
+	}
+
+
+
+	// ------------------------------backup------------------------
+    public String getClassPath_V1(){
+
+		StringBuffer buffer = new StringBuffer();
+		for(int i=0;i<this.clzPaths.size();i++){
+			buffer.append(this.clzPaths.get(i));
+			if(i<this.clzPaths.size()-1){
+				buffer.append(";");
+			}
+		}
+		return buffer.toString();
+	}
+
+	private byte[] loadClassFile_V1(String clzFileName) {
+
+		BufferedInputStream bis = null;
+
+		try {
+
+			File f = new File(clzFileName);
+
+
+			bis = new BufferedInputStream(new FileInputStream(f));
+
+			ByteArrayOutputStream bos = new ByteArrayOutputStream();
+
+
+			byte[] buffer = new byte[1024];
+			int length = -1;
+
+			while((length = bis.read(buffer)) != -1){
+				bos.write(buffer, 0, length);				
+			}
+
+			byte [] codes = bos.toByteArray();
+
+			return codes;
+
+		} catch(IOException e){
+			e.printStackTrace();
+
+		} finally{
+			if(bis != null){
+				try {
+					bis.close();
+				} catch (IOException e) {					
+					e.printStackTrace();
+				}
+			}
+		}
+		return null;
+
+	}
+
+
+
+
+
+}

group19/1294642551/test/LRU/LRUPageFrameTest.java

@@ -0,0 +1,34 @@
+package LRU;
+
+import  org.junit.Assert;
+
+import org.junit.Test;
+
+
+public class LRUPageFrameTest {
+
+	@Test
+	public void testAccess() {
+		LRUPageFrame frame = new LRUPageFrame(3);
+		frame.access(7);
+		frame.access(0);
+		frame.access(1);
+		Assert.assertEquals("1,0,7", frame.toString());
+		frame.access(2);
+		Assert.assertEquals("2,1,0", frame.toString());
+		frame.access(0);
+		Assert.assertEquals("0,2,1", frame.toString());
+		frame.access(0);
+		Assert.assertEquals("0,2,1", frame.toString());
+		frame.access(3);
+		Assert.assertEquals("3,0,2", frame.toString());
+		frame.access(0);
+		Assert.assertEquals("0,3,2", frame.toString());
+		frame.access(4);
+		Assert.assertEquals("4,0,3", frame.toString());
+		frame.access(5);
+		Assert.assertEquals("5,4,0", frame.toString());
+
+	}
+
+}