add cache algorithm

Author: robert

README.md

@@ -1 +1 @@
-# simplealgorithmcom.algorithm.digest 信息摘要，快速计算文件的MD5<br>com.algorithm.list 实现链表和List的基本操作<br>com.algorithm.tree 树的实现，二分查找<br>com.algorithm UnionFind 并查集<br>com.algorithm PrimeNumber 打表法判断素数<br>com.algorithm JavaSort 简单冒泡排序<br>com.algorithm TestAsynTreadXunlei 开启3个线程，这3个线程的ID分别为A、B、C，每个线程将自己的ID在屏幕上打印10遍，要求输出结果必须按ABC的顺序显示；如：ABCABC….依次递推。<br>
+# simplealgorithmcom.algorithm.digest 信息摘要，快速计算文件的MD5<br>com.algorithm.list 实现链表和List的基本操作<br>com.algorithm.tree 树的实现，二分查找<br>com.algorithm UnionFind 并查集<br>com.algorithm PrimeNumber 打表法判断素数<br>com.algorithm JavaSort 简单冒泡排序<br>com.algorithm TestAsynTreadXunlei 开启3个线程，这3个线程的ID分别为A、B、C，每个线程将自己的ID在屏幕上打印10遍，要求输出结果必须按ABC的顺序显示；如：ABCABC….依次递推。<br>com.algorithm.cache 缓存策略，FIFO,LRU缓存的具体实现

src/com/algorithm/cache/BaseCache.java

@@ -0,0 +1,60 @@
+package com.algorithm.cache;
+
+import java.sql.ResultSet;
+import java.util.LinkedHashMap;
+
+/**
+ * 
+ * @author chao
+ * @param <V>
+ * @param <K>
+ *
+ */
+public class BaseCache<K, V> implements ICache<K, V> {
+	protected int currentsize = 0;
+	protected LinkedHashMap<K, V> hashMap = new LinkedHashMap<>();
+
+	@Override
+	public void put(K key, V value) {
+		V oldobj = hashMap.get(key);
+		if (oldobj != null) {
+			currentsize = currentsize - getObjSize(oldobj);
+			hashMap.remove(key);
+		}
+		currentsize = currentsize + getObjSize(value);
+		reset();
+		hashMap.put(key, value);
+
+	}
+
+	@Override
+	public V get(K key) {
+		return hashMap.get(key);
+	}
+
+	@Override
+	public V remove(K key) {
+		V valueObject = hashMap.remove(key);
+		currentsize = currentsize - getObjSize(valueObject);
+		return valueObject;
+	}
+
+	protected void reset() {
+
+	}
+
+	public int getObjSize(V obj) {
+		if (obj == null) {
+			return 0;
+		} else if (obj instanceof String) {
+			return ((String) obj).getBytes().length;
+		}
+		return 1;
+	}
+
+	public void printAll() {
+		System.out.println("currentSize: " + currentsize);
+		System.out.println("info:" + hashMap);
+	}
+
+}

src/com/algorithm/cache/CacheTest.java

@@ -0,0 +1,37 @@
+package com.algorithm.cache;
+
+public class CacheTest {
+
+	public static void main(String[] args) {
+		test();
+	}
+
+	public static void test() {
+		FIFOCache<String, String> fifoCache = new FIFOCache<String, String>(10);
+		fifoCache.put("1", "aaa");
+		fifoCache.printAll();
+		fifoCache.put("2", "bbb");
+		fifoCache.printAll();
+		fifoCache.put("1", "bdd");
+		fifoCache.printAll();
+		fifoCache.put("1", "dddddddddd");
+		fifoCache.printAll();
+		fifoCache.put("3", "e");
+		fifoCache.printAll();
+
+		System.out.println("===============");
+		LRUCache<String, String> lruCache = new LRUCache<>(10);
+		lruCache.put("1", "aaaaaa");
+		lruCache.printAll();
+		lruCache.put("1", "b");
+		lruCache.printAll();
+		lruCache.put("2", "c");
+		lruCache.printAll();
+		lruCache.put("3", "dd");
+		lruCache.printAll();
+		lruCache.put("1", "ee");
+		lruCache.printAll();
+		lruCache.put("9", "dddddd");
+		lruCache.printAll();
+	}
+}

src/com/algorithm/cache/FIFOCache.java

@@ -0,0 +1,50 @@
+package com.algorithm.cache;
+
+import java.util.LinkedList;
+
+/**
+ * 
+ * @author chao
+ * @param <T>
+ *
+ */
+public class FIFOCache<K, V> extends BaseCache<K, V> {
+	private int maxsize = DEFAULT_SIZE;
+
+	public FIFOCache(int size) {
+		if (maxsize <= 0) {
+			return;
+		}
+		this.maxsize = size;
+	}
+
+	public void put(K key, V value) {
+		int valuesize = getObjSize(value);
+		if (valuesize > maxsize) {
+			System.out.println("error : the object is too large!!!");
+			return;
+		}
+		V oldobj = hashMap.get(key);
+		if (oldobj != null) {
+			currentsize = currentsize - getObjSize(oldobj);
+		}
+		currentsize = currentsize + getObjSize(value);
+		reset();
+		hashMap.put(key, value);
+
+	}
+
+	protected void reset() {
+		while (currentsize > maxsize) {
+			super.remove(hashMap.keySet().iterator().next());
+
+		}
+	}
+
+	public void printAll() {
+		super.printAll();
+		System.out.println("keyset: " + hashMap.keySet());
+		System.out.println();
+		// System.out.println("max size: " + maxsize);
+	}
+}

src/com/algorithm/cache/ICache.java

@@ -0,0 +1,18 @@
+package com.algorithm.cache;
+
+/**
+ * 
+ * @author chao
+ * @param <K>
+ * @param <V>
+ *
+ */
+public interface ICache<K, V> {
+	public static final int DEFAULT_SIZE = 10;
+
+	public void put(K key, V value);
+
+	public V get(K key);
+
+	public V remove(K key);
+}

src/com/algorithm/cache/LRUCache.java

@@ -0,0 +1,41 @@
+package com.algorithm.cache;
+
+/**
+ * 
+ * @author chao
+ *
+ */
+public class LRUCache<K, V> extends BaseCache<K, V> {
+	private int maxsize = DEFAULT_SIZE;
+
+	public LRUCache(int size) {
+		if (maxsize <= 0) {
+			return;
+		}
+		this.maxsize = size;
+	}
+
+	@Override
+	public void put(K key, V value) {
+		int valuesize = getObjSize(value);
+		if (valuesize > maxsize) {
+			System.out.println("error : the object is too large!!!");
+			return;
+		}
+		super.put(key, value);
+
+	}
+
+	protected void reset() {
+		while (currentsize > maxsize) {
+			super.remove(hashMap.keySet().iterator().next());
+		}
+	}
+
+	public void printAll() {
+		super.printAll();
+		System.out.println("keyset:" + hashMap.keySet());
+		System.out.println();
+		// System.out.println("max size" + maxsize);
+	}
+}

src/com/algorithm/digest/DigestMain.java

@@ -1,18 +1,7 @@
 package com.algorithm.digest;
 
 import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.math.BigInteger;
-import java.nio.MappedByteBuffer;
-import java.nio.channels.FileChannel;
-import java.nio.channels.FileChannel.MapMode;
-import java.security.DigestOutputStream;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
+
 /**
  * 
  * @author robert