Merge pull request onlyliuxin#51 from Wrecksoul/master

完成jvm第一次作业与LRU

group17/82427129/JavaUtil/src/main/java/com/coderising/jvm/loader/ClassFileLoader.java

@@ -0,0 +1,104 @@
+package com.coderising.jvm.loader;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+public class ClassFileLoader {
+	private static final int BUFFERSIZE = 1024;
+	private List<String> clzPaths = new ArrayList<String>();
+
+	public byte[] readBinaryCode(String className) {
+		if (clzPaths.size()<=0){
+			return null;
+		}
+		for (int i = 0; i < clzPaths.size(); i++) {
+			String path = clzPaths.get(i) + convertName(className);
+			File f = new File(path);
+			if(f.exists()){
+				try {
+					return readFile(f);
+				} catch (FileNotFoundException e) {
+					e.printStackTrace();
+				}
+			}else{
+				f = null;
+				continue;
+			}
+		}
+		System.err.println("classpath:" +getClassPath()+ "class:" + convertName(className)+" not found.");
+		return null;
+	}
+	/**
+	 * 文件读取二进制字节流
+	 * @param f
+	 * @return
+	 * @throws FileNotFoundException
+	 */
+	private byte[] readFile(File f) throws FileNotFoundException {
+		FileInputStream fis = new FileInputStream(f);
+		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		byte[] b = new byte[BUFFERSIZE];
+		try {
+			int len = 0;
+			while((len = fis.read(b))!=-1){
+				baos.write(b,0,len);
+			}
+		} catch (IOException e) {
+			e.printStackTrace();
+		} finally{
+			try {
+				fis.close();
+				baos.flush();
+				baos.close();
+			} catch (IOException e) {
+				e.printStackTrace();
+			}
+
+		}
+		return baos.toByteArray();
+	}
+
+	public void addClassPath(String path) {
+		clzPaths.add(path);
+	}
+
+	public String getClassPath() {
+		StringBuilder sb = new StringBuilder();
+		for (int i = 0; i < clzPaths.size(); i++) {
+			sb.append(clzPaths.get(i)).append(";");
+		}
+		int len = sb.length();
+		if(len!=0){
+			sb.deleteCharAt(len-1);
+		}
+		return sb.toString();
+	}
+
+	/**
+	 * convert className to FilePath style className <br/>
+	 * For example:com.sun.lang to \com\sun\lang
+	 * 
+	 * @param className
+	 * @return FilePath style className
+	 */
+	private String convertName(String className) {
+		StringBuilder sb = new StringBuilder();
+		String[] pack = className.split("\\.");
+		for (int i = 0; i < pack.length; i++) {
+			sb.append("\\").append(pack[i]);
+		}
+		sb.append(".class");
+		return sb.toString();
+	}
+
+	public static void main(String[] args) {
+		String d = "com.taiji.array.Load";
+		ClassFileLoader cc = new ClassFileLoader();
+		System.out.print(cc.convertName(d));
+	}
+}

group17/82427129/JavaUtil/src/main/java/com/coderising/jvm/test/EmployeeV1.java

@@ -0,0 +1,29 @@
+package com.coderising.jvm.test;
+
+public class EmployeeV1 {
+	private String name;
+	private int age;
+
+	public EmployeeV1(String name, int age) {
+		this.name = name;
+		this.age = age;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public void setAge(int age) {
+		this.age = age;
+	}
+
+	public void sayHello() {
+		System.out.println("Hello , this is class Employee ");
+	}
+
+	public static void main(String[] args) {
+		EmployeeV1 p = new EmployeeV1("Andy", 29);
+		p.sayHello();
+
+	}
+}

group17/82427129/JavaUtil/src/main/java/com/coding/basic/LRU/LRUPageFrame.java

@@ -0,0 +1,147 @@
+package com.coding.basic.LRU;
+
+public class LRUPageFrame {
+	private int capacity;
+	private Node first;// 链表头
+	private Node last;// 链表尾
+	private int length = 0;
+
+	public LRUPageFrame(int capacity) {
+		this.capacity = capacity;
+	}
+
+	/**
+	 * 获取缓存中对象
+	 * 
+	 * @param key
+	 * @return
+	 */
+	public void access(int pageNum) {
+		// this loop select for pageNum,grow it first when 'found'.
+		for (Node n = first; n != null; n = n.next) {
+			if (n.pageNum == pageNum) {
+				growFirst(n);
+				return;
+			}
+		}
+		// if didn't found it
+		if (ensureFull()) {
+			removeLast();
+		}
+		add(pageNum);
+	}
+
+	private void add(int pageNum) {
+		if (isEmpty()) {
+			Node newNode = new Node(null, null, pageNum);
+			first = newNode;
+			last = newNode;
+			length++;
+		} else {
+			addToFirst(pageNum);
+		}
+	}
+
+	private void addToFirst(int pageNum) {
+		Node newNode = new Node(null, null, pageNum);
+		newNode.next = first;
+		first.prev = newNode;
+		first = newNode;
+		length++;
+	}
+
+	/**
+	 * ensure the LRUPageFrame is full or Not
+	 * 
+	 * @return if full return true,else false
+	 */
+	private boolean ensureFull() {
+		if (length < capacity) {
+			return false;
+		} else {
+			return true;
+		}
+	}
+
+	/**
+	 * grow the Node'position to first
+	 * 
+	 * @param n
+	 */
+	private void growFirst(Node n) {
+		// if the node is already first ,return.
+		if (first.pageNum == n.pageNum) {
+			return;
+		}
+		remove(n);
+		addToFirst(n.pageNum);
+	}
+
+	private void remove(Node n) {
+		if (isEmpty()) {
+			return;
+		}
+		if (n.next == null) {
+			removeLast();
+			return;
+		}
+		if (n.prev == null) {
+			removeFirst();
+			return;
+		}
+		Node prev = n.prev;
+		Node next = n.next;
+		n.next = null;
+		n.prev = null;
+		prev.next = next;
+		next.prev = prev;
+		length--;
+	}
+
+	private void removeFirst() {
+		Node next = first.next;
+		first.next = null;
+		first = next;
+	}
+
+	private void removeLast() {
+		Node prev = last.prev;
+		prev.next = null;
+		last.prev = null;
+		last = prev;
+		length--;
+	}
+	/**
+	 * ensure the LRUPageFrame is empty or Not.
+	 * @return
+	 */
+	public boolean isEmpty() {
+		return length < 1;
+	}
+
+	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();
+	}
+
+	private static class Node {
+		Node prev;
+		Node next;
+		int pageNum;
+
+		Node(Node prev, Node next, int pageNum) {
+			this.prev = prev;
+			this.next = next;
+			this.pageNum = pageNum;
+		}
+	}
+}

group17/82427129/JavaUtil/src/test/java/com/coderising/jvm/loader/ClassFileLoaderTest.java

@@ -0,0 +1,73 @@
+package com.coderising.jvm.loader;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ClassFileLoaderTest {
+	static String path1 = "C:\\Users\\liuxin\\git\\coding2017\\liuxin\\mini-jvm\\bin";
+	static String path2 = "D:\\workProgram\\GitRepo\\coding2017\\group17\\82427129\\JavaUtil\\target\\classes";
+	@Before
+	public void setUp() throws Exception {
+	}
+
+	@After
+	public void tearDown() throws Exception {
+	}
+
+	@Test
+	public void testClassFileLength() {		
+
+		ClassFileLoader loader = new ClassFileLoader();
+		loader.addClassPath(path2);
+
+		String className = "com.coderising.jvm.test.EmployeeV1";
+
+		byte[] byteCodes = loader.readBinaryCode(className);
+
+		// 注意：这个字节数可能和你的JVM版本有关系， 你可以看看编译好的类到底有多大
+		Assert.assertEquals(1056, byteCodes.length);
+
+	}
+
+	@Test
+	public void testGetClassPath() {
+		ClassFileLoader loader = new ClassFileLoader();
+		loader.addClassPath(path1);
+		loader.addClassPath(path2);
+
+		String clzPath = loader.getClassPath();
+
+		Assert.assertEquals(path1+";"+path2,clzPath);
+	}
+
+	@Test	
+	public void testMagicNumber(){
+    	ClassFileLoader loader = new ClassFileLoader();
+		loader.addClassPath(path2);
+		String className = "com.coderising.jvm.test.EmployeeV1";
+		byte[] byteCodes = loader.readBinaryCode(className);
+		byte[] codes = new byte[]{byteCodes[0],byteCodes[1],byteCodes[2],byteCodes[3]};
+
+
+		String acctualValue = this.byteToHexString(codes);
+
+		Assert.assertEquals("cafebabe", acctualValue);
+	}
+
+	private String byteToHexString(byte[] codes) {
+		StringBuffer buffer = new StringBuffer();
+		for (int i = 0; i < codes.length; i++) {
+			byte b = codes[i];
+			int value = b & 0xFF;
+			String strHex = Integer.toHexString(value);
+			if (strHex.length() < 2) {
+				strHex = "0" + strHex;
+			}
+			buffer.append(strHex);
+		}
+		return buffer.toString();
+	}
+
+}

group17/82427129/JavaUtil/src/test/java/com/coding/basic/LRU/LRUPageFrameTest.java

@@ -0,0 +1,29 @@
+package com.coding.basic.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());
+	}
+
+}