Merge branch 'master' of https://github.com/MrGPanPan/coding2017

group11/1178243325/week03/readme.md

@@ -3,7 +3,7 @@
 - 17-03-09：TDD和第二次作业讲解
 - 17-03-12：职场15年
 
-## 第二周作业（3-6 至 3-12）
+## 第三周作业（3-6 至 3-12）
 - 实现第二个大作业：多线程下载文件，支持断点续传
 - 5道数据结构习题
 

group11/1178243325/week06/build.gradle

@@ -0,0 +1,13 @@
+apply plugin: 'java'
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	compile("commons-io:commons-io:2.4")
+	//compile("commons-lang:commons-lang:2.6")
+	compile("org.apache.commons:commons-lang3:3.4")
+	testCompile("junit:junit:4.12")
+}
+

group11/1178243325/week06/readme.md

@@ -0,0 +1,16 @@
+## 讲课内容：
+- 17-03-27：JVM第一周
+- 17-03-29：JVM之classLoader
+
+## 第六周作业（3-27 至 04-02)
+- 完成对一个.class文件的读取和对.class文件开头四个字节的魔数的判断需要实现ClassLoader.java
+- 实现LRU算法
+- 一篇文章
+
+## 完成情况：
+- ClassLoader.java已完
+- LRU已完
+- [文章](http://www.jianshu.com/p/02a8b4ee4596)
+
+## 我的收获：
+使用开源工具读取文件，并利用工作类进行字符转换．LRU算法(双链表操作)，但是更重要的抽象化思想．

group11/1178243325/week06/src/main/java/com/sprint/basic/LRUPageFrame.java

@@ -0,0 +1,117 @@
+package com.sprint.basic;
+
+public class LRUPageFrame {
+
+	/**
+	 * 用双向链表实现LRU算法
+	 */
+
+	private static class Node {
+		Node prev;
+		Node next;
+		int pageNum;
+
+		Node()  {
+
+		}
+	}
+
+	private int capacity;
+	private int currentSize;
+	private Node first;
+	private Node last;
+
+	public LRUPageFrame(int capacity) {
+		this.currentSize = 0;
+		this.capacity = capacity;	
+	}
+
+	/**
+	 *
+	 */
+	public void access(int pageNum) {
+		Node node = find(pageNum);
+		if (node != null) {
+			moveExistingNodeToHead(node);
+		} else {
+			node = new Node();
+			node.pageNum = pageNum;
+			if (currentSize >= capacity) {
+				removeLast();
+			}
+			addNewNodeToHead(node);
+		}
+	}	
+
+	private Node find(int pageNum) {
+		Node node = first;
+		while (node != null) {
+			if (node.pageNum == pageNum) {
+				return node;
+			}
+			node = node.next;
+		}
+		return null;
+	}
+
+	private void moveExistingNodeToHead(Node node) {
+		if (node == first) {
+			return;
+		} else if (node == last) {
+			Node prevNode = node.prev;
+			prevNode.next = null;
+			last.prev = null;
+			last = prevNode;
+		} else {
+			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 void removeLast() {
+		Node prev = last.prev;
+		prev.next = null;
+		last.prev = null;
+		last = prev;
+		this.currentSize--;
+	}
+
+	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 boolean isEmpty() {
+		return (first == null) && (last == null);
+	}
+	@Override
+	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();
+	}
+}

group11/1178243325/week06/src/main/java/com/sprint/jvm/clz/ClassFile.java

@@ -0,0 +1,9 @@
+package com.sprint.jvm.clz;
+
+public class ClassFile {
+	private final String cafebabe = "cafebabe";
+
+	public String getCafebabe() {
+		return cafebabe;
+	}
+}

group11/1178243325/week06/src/main/java/com/sprint/jvm/loader/ByteCodeIterator.java

@@ -0,0 +1,17 @@
+package com.sprint.jvm.loader;
+
+import com.sprint.jvm.util.Util;
+import java.util.Arrays;
+public class ByteCodeIterator {
+	byte[] codes;
+	int pos = 0;
+	ByteCodeIterator(byte[] codes) {
+		this.codes = codes;
+	}
+
+	public String nextU4ToHexString() {
+		return Util.byteToHexString(new byte[] {codes[pos++], codes[pos++], codes[pos++], codes[pos++]});
+	}
+
+
+}

group11/1178243325/week06/src/main/java/com/sprint/jvm/loader/ClassFileLoader.java

@@ -0,0 +1,49 @@
+package com.sprint.jvm.loader;
+
+import com.sprint.jvm.clz.ClassFile;
+import java.io.IOException;
+import java.io.File;
+import java.io.FileInputStream;
+import java.util.List;
+import java.util.ArrayList;
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.StringUtils;
+
+public class ClassFileLoader {
+	List<String> clzPaths = new ArrayList<>();
+
+	public ClassFile loadClass(String className) {
+		byte[] codes = this.readBinaryCode(className);
+		ClassFileParser parser = new ClassFileParser();
+		return parser.parse(codes);
+	}
+
+	public void addClassPath(String clzPath) {
+		if (this.clzPaths.contains(clzPath)) {
+			return;
+		}
+		this.clzPaths.add(clzPath);
+	}
+
+	private 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) {
+		File f = new File(clzFileName);
+		try {
+			return IOUtils.toByteArray(new FileInputStream(f));	
+		} catch (IOException e) {
+			e.printStackTrace();
+			return null;
+		}
+	}
+}

group11/1178243325/week06/src/main/java/com/sprint/jvm/loader/ClassFileParser.java

@@ -0,0 +1,14 @@
+package com.sprint.jvm.loader;
+
+import com.sprint.jvm.clz.ClassFile;
+public class ClassFileParser {
+	public ClassFile parse(byte[] codes) {
+		ClassFile clzFile = new ClassFile(); 		
+		ByteCodeIterator iter = new ByteCodeIterator(codes);
+		String magicNumber = iter.nextU4ToHexString();
+		if (!"cafebabe".equals(magicNumber)) {
+			return null;
+		}
+		return clzFile;
+	}
+}

group11/1178243325/week06/src/main/java/com/sprint/jvm/util/Util.java

@@ -0,0 +1,17 @@
+package com.sprint.jvm.util;
+
+public class Util {
+	public static 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();
+	}
+}	

group11/1178243325/week06/src/test/java/com/sprint/basic/LRUPageFrameTest.java

@@ -0,0 +1,33 @@
+package com.sprint.basic;
+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());
+
+	}
+
+}

group11/1178243325/week06/src/test/java/com/sprint/jvm/loader/ClassFileLoaderTest.java

@@ -0,0 +1,23 @@
+package com.sprint.jvm.loader;
+
+import com.sprint.jvm.clz.ClassFile;
+import org.junit.Test;
+import org.junit.Assert;
+public class ClassFileLoaderTest {
+
+	private static final String FULL_QUALTFIED_CLASS_NAME = "com/sprint/jvm/EmployeeV1";
+
+	static String path1 = "/home/sprint/java/code/coding2017/group11/1178243325/week06/build/classes/test";
+	static ClassFile clzFile = null;
+	static {
+		ClassFileLoader loader = new ClassFileLoader();
+		loader.addClassPath(path1);
+		String className = "com.sprint.jvm.loader.EmployeeV1"; 
+		clzFile = loader.loadClass(className);
+	}
+
+	@Test
+	public void test() {
+		Assert.assertEquals("cafebabe", clzFile.getCafebabe());
+	}
+}

group11/1178243325/week06/src/test/java/com/sprint/jvm/loader/EmployeeV1.java

@@ -0,0 +1,28 @@
+package com.sprint.jvm.loader;
+
+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", 20);
+		p.sayHello();
+	}
+}

group11/996108220/src/com/coderising/jvm/clz/AccessFlag.java

@@ -0,0 +1,25 @@
+package com.coderising.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;
+	}
+
+}