jvm第一周作业代码

group17/240094626/work_jvm_1/data-structure/src/com/coding/basic/linklist/LRUPageFrame.java

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+package com.coding.basic.linklist;
+
+/**
+ * 用双向链表实现LRU算法
+ * @author liuxin
+ *
+ */
+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.capacity = capacity;
+		currentSize = 0;
+	}
+
+	/**
+	 * 获取缓存中对象
+	 * 
+	 * @param key
+	 * @return
+	 */
+	public void access(int pageNum) {
+
+		// 判断缓存是否命中
+		Node n = find(pageNum);
+		if(n != null){
+			// 命中，则把节点提到表头
+			moveNodeToHead(n);
+		}else{
+			// 若未命中，新增节点放到表头，如果链表长度超过capacity，移除链表尾部节点
+			n = new Node();
+			n.pageNum = pageNum;
+
+			if(currentSize >= capacity){
+				removeLast();
+			}
+			addNodeToHead(n);
+		}
+	}
+
+
+
+	private void addNodeToHead(Node n) {
+		if(first == null){
+			first = n;
+			last = n;
+		}else{
+			n.next = first;
+			first.prev = n;
+			first = n;
+		}
+		currentSize++;
+	}
+
+	private void removeLast() {
+		Node prevN = last.prev;
+		prevN.next = null;
+		last.prev = null;
+		last = prevN;
+		currentSize--;
+	}
+
+	private void moveNodeToHead(Node n) {
+		if(n == first){
+			return ;
+		}else if(n == last){
+			Node preN = n.prev;
+			preN.next = null;
+			last.prev = null;
+			last = preN;
+		}else{
+			// 中间节点 
+			Node preN = n.prev;
+			Node nextN = n.next;
+			preN.next = nextN;
+			nextN.prev = preN;
+		}
+		n.prev = null;
+		n.next = first;
+		first.prev = n;
+		first = n;
+	}
+
+	private Node find(int pageNum) {
+		Node n = first;
+		while(n != null){
+			if(n.pageNum == pageNum){
+				return n;
+			}
+			n = n.next;
+		}
+		return 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();
+	}
+
+}

group17/240094626/work_jvm_1/data-structure/src/com/coding/basic/linklist/LRUPageFrameTest.java

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+package com.coding.basic.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());
+	}
+
+}

group17/240094626/work_jvm_1/data-structure/src/com/coding/basic/linklist/LinkedList.java

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+package com.coding.basic.linklist;
+
+import com.coding.basic.Iterator;
+import com.coding.basic.List;
+
+public class LinkedList implements List {
+
+	private Node head;
+
+	public void add(Object o){
+
+	}
+	public void add(int index , Object o){
+
+	}
+	public Object get(int index){
+		return null;
+	}
+	public Object remove(int index){
+		return null;
+	}
+
+	public int size(){
+		return -1;
+	}
+
+	public void addFirst(Object o){
+
+	}
+	public void addLast(Object o){
+
+	}
+	public Object removeFirst(){
+		return null;
+	}
+	public Object removeLast(){
+		return null;
+	}
+	public Iterator iterator(){
+		return null;
+	}
+
+
+	private static  class Node{
+		Object data;
+		Node next;
+
+	}
+
+	/**
+	 * 把该链表逆置
+	 * 例如链表为 3->7->10 , 逆置后变为  10->7->3
+	 */
+	public  void reverse(){		
+
+	}
+
+	/**
+	 * 删除一个单链表的前半部分
+	 * 例如：list = 2->5->7->8 , 删除以后的值为 7->8
+	 * 如果list = 2->5->7->8->10 ,删除以后的值为7,8,10
+
+	 */
+	public  void removeFirstHalf(){
+
+	}
+
+	/**
+	 * 从第i个元素开始， 删除length 个元素 ， 注意i从0开始
+	 * @param i
+	 * @param length
+	 */
+	public  void remove(int i, int length){
+
+	}
+	/**
+	 * 假定当前链表和listB均包含已升序排列的整数
+	 * 从当前链表中取出那些listB所指定的元素
+	 * 例如当前链表 = 11->101->201->301->401->501->601->701
+	 * listB = 1->3->4->6
+	 * 返回的结果应该是[101,301,401,601]  
+	 * @param list
+	 */
+	public  int[] getElements(LinkedList list){
+		return null;
+	}
+
+	/**
+	 * 已知链表中的元素以值递增有序排列，并以单链表作存储结构。
+	 * 从当前链表中中删除在listB中出现的元素 
+
+	 * @param list
+	 */
+
+	public  void subtract(LinkedList list){
+
+	}
+
+	/**
+	 * 已知当前链表中的元素以值递增有序排列，并以单链表作存储结构。
+	 * 删除表中所有值相同的多余元素（使得操作后的线性表中所有元素的值均不相同）
+	 */
+	public  void removeDuplicateValues(){
+
+	}
+
+	/**
+	 * 已知链表中的元素以值递增有序排列，并以单链表作存储结构。
+	 * 试写一高效的算法，删除表中所有值大于min且小于max的元素（若表中存在这样的元素）
+	 * @param min
+	 * @param max
+	 */
+	public  void removeRange(int min, int max){
+
+	}
+
+	/**
+	 * 假设当前链表和参数list指定的链表均以元素依值递增有序排列（同一表中的元素值各不相同）
+	 * 现要求生成新链表C，其元素为当前链表和list中元素的交集，且表C中的元素有依值递增有序排列
+	 * @param list
+	 */
+	public  LinkedList intersection( LinkedList list){
+		return null;
+	}
+}

group17/240094626/work_jvm_1/src/com/coderising/jvm/loader/ClassFileLoader.java

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+package com.coderising.jvm.loader;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+
+
+public class ClassFileLoader {
+
+	private List<String> clzPaths = new ArrayList<String>();
+
+	public byte[] readBinaryCode(String className) {
+		if(null == className || "".equals(className)){
+			return null;
+		}
+		className = className.replace(".", File.separator)+".class";
+		Iterator<String> it = clzPaths.iterator();
+		byte[] bytes = null;
+		while(it.hasNext() && bytes == null){
+			String filePath = it.next()+File.separator+className;
+			bytes = getClassFile(filePath);
+		}
+		return bytes;	
+
+	}
+
+
+	private byte[] getClassFile(String filePath) {
+		ByteArrayOutputStream bos = new ByteArrayOutputStream();
+		try {
+			InputStream is = new FileInputStream(new File(filePath));
+			byte[] buffer = new byte[1024];
+			int len = 0;
+			while((len=is.read(buffer)) > 0){
+				bos.write(buffer,0, len);
+			}
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+		return bos.toByteArray();
+	}
+
+
+	public void addClassPath(String path) {
+		if(null != path && !"".equals(path)){
+			clzPaths.add(path);
+		}
+	}
+
+
+
+	public String getClassPath(){
+		StringBuilder sb = new StringBuilder();
+		Iterator<String> it = clzPaths.iterator();
+		while(it.hasNext()){
+			if(sb.length() > 0){
+				sb.append(";");
+			}
+			sb.append(it.next());
+		}
+		return sb.toString();
+	}
+
+
+
+
+
+}