Merge pull request #51 from wa122as/master

补交第四次作业

group15/1521_653895972/src/task4/jvm/loader/ClassFileLoader.java

@@ -0,0 +1,44 @@
+package task4.jvm.loader;
+
+import org.apache.commons.lang3.StringUtils;
+
+import java.io.BufferedInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+
+
+
+public class ClassFileLoader {
+
+	private List<String> clzPaths = new ArrayList<String>();
+
+	public byte[] readBinaryCode(String className) throws Exception {
+		String filePath = clzPaths.get(0)+File.separatorChar+className.replace('.',File.separatorChar)+".class";
+		File file = new File(filePath);
+
+		BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
+		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+		byte[] buffer = new byte[1024];
+		int len = 0;
+		while((len = bis.read(buffer)) != -1){
+			baos.write(buffer,0,len);
+		}
+		return baos.toByteArray();		
+	}
+
+	public void addClassPath(String path) {
+		if (clzPaths.contains(path))
+			return;
+		clzPaths.add(path);
+	}
+
+	public String getClassPath(){
+		return StringUtils.join(clzPaths,";");
+	}
+
+}

group15/1521_653895972/src/task4/jvm/test/ClassFileloaderTest.java

@@ -0,0 +1,83 @@
+package task4.jvm.test;
+
+import org.junit.After;
+import  org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import task4.jvm.loader.ClassFileLoader;
+
+
+public class ClassFileloaderTest {
+
+
+	static String path1 = "D:\\oneces\\GitHub\\coding2017\\group15\\1521_653895972\\out\\production\\1521_653895972";
+	static String path2 = "C:\temp";
+
+
+
+	@Before
+	public void setUp() throws Exception {		 
+	}
+
+	@After
+	public void tearDown() throws Exception {
+	}
+
+	@Test
+	public void testClassPath(){		
+
+		ClassFileLoader loader = new ClassFileLoader();
+		loader.addClassPath(path1);
+		loader.addClassPath(path2);
+
+		String clzPath = loader.getClassPath();
+		Assert.assertEquals(path1+";"+path2,clzPath);
+
+	}
+
+	@Test
+	public void testClassFileLength() throws Exception {		
+
+		ClassFileLoader loader = new ClassFileLoader();
+		loader.addClassPath(path1);
+
+		String className = "task4.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(1038, byteCodes.length);
+
+	}
+
+
+    @Test	
+	public void testMagicNumber() throws Exception{
+    	ClassFileLoader loader = new ClassFileLoader();
+		loader.addClassPath(path1);
+		String className = "task4.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();
+	}
+
+}

group15/1521_653895972/src/task4/jvm/test/EmployeeV1.java

@@ -0,0 +1,28 @@
+package task4.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();    
+
+    }
+}

group15/1521_653895972/src/task4/linklist/LRUPageFrame.java

@@ -0,0 +1,157 @@
+package task4.linklist;
+
+
+public class LRUPageFrame {
+
+    private static class Node {
+
+        Node prev;
+        Node next;
+        int pageNum;
+
+        Node() {
+        }
+    }
+
+    private int capacity;
+
+    private int currentSize;
+    private Node first;// 链表头
+    private Node last;// 链表尾
+
+
+    public LRUPageFrame(int capacity) {
+        this.currentSize = 0;
+        this.capacity = capacity;
+
+    }
+
+    /**
+     * 获取缓存中对象
+     *
+     * @param pageNum
+     * @return
+     */
+    public void access(int pageNum) {
+
+        Node node = find(pageNum);
+        //在该队列中存在， 则提到队列头
+        if (node != null) {
+
+            moveExistingNodeToHead(node);
+
+        } else {
+
+            node = new Node();
+            node.pageNum = pageNum;
+
+            // 缓存容器是否已经超过大小.
+            if (currentSize >= capacity) {
+                removeLast();
+
+            }
+
+            addNewNodetoHead(node);
+
+
+        }
+    }
+
+    private void addNewNodetoHead(Node node) {
+
+        if (isEmpty()) {
+
+            node.prev = null;
+            node.next = null;
+            first = node;
+            last = node;
+
+        } else {
+            node.prev = null;
+            node.next = first;
+            first.prev = node;
+            first = node;
+        }
+        this.currentSize++;
+    }
+
+    private Node find(int data) {
+
+        Node node = first;
+        while (node != null) {
+            if (node.pageNum == data) {
+                return node;
+            }
+            node = node.next;
+        }
+        return null;
+
+    }
+
+
+    /**
+     * 删除链表尾部节点 表示 删除最少使用的缓存对象
+     */
+    private void removeLast() {
+        Node prev = last.prev;
+        prev.next = null;
+        last.prev = null;
+        last = prev;
+        this.currentSize--;
+    }
+
+    /**
+     * 移动到链表头，表示这个节点是最新使用过的
+     *
+     * @param node
+     */
+    private void moveExistingNodeToHead(Node node) {
+
+        if (node == first) {
+
+            return;
+        } else if (node == last) {
+            //当前节点是链表尾， 需要放到链表头
+            Node prevNode = node.prev;
+            prevNode.next = null;
+            last.prev = null;
+            last = prevNode;
+
+        } else {
+            //node 在链表的中间， 把node 的前后节点连接起来
+            Node prevNode = node.prev;
+            prevNode.next = node.next;
+
+            Node nextNode = node.next;
+            nextNode.prev = prevNode;
+
+
+        }
+
+        node.prev = null;
+        node.next = first;
+        first.prev = node;
+        first = node;
+
+    }
+
+    private boolean isEmpty() {
+        return (first == null) && (last == null);
+    }
+
+    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();
+    }
+
+
+}

group15/1521_653895972/src/task4/linklist/LRUPageFrameTest.java

@@ -0,0 +1,34 @@
+package task4.linklist;
+
+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());
+		System.out.println("3232");
+	}
+
+}

group15/1521_653895972/src/task5/jvm/clz/AccessFlag.java

@@ -0,0 +1,25 @@
+package task5.jvm.clz;
+
+public class AccessFlag {
+	private int flagValue;
+
+	public AccessFlag(int value) {
+		this.flagValue = value;
+	}
+
+	public int getFlagValue() {
+		return flagValue;
+	}
+
+	public void setFlagValue(int flag) {
+		this.flagValue = flag;
+	}
+
+	public boolean isPublicClass(){
+		return (this.flagValue & 0x0001) != 0;
+	}
+	public boolean isFinalClass(){
+		return (this.flagValue & 0x0010) != 0;
+	}
+
+}