✨ Introducing new features. base on LinkedHashMap

crossoverJie · crossoverJie · commit d02ce84cb9c5 · 2018-04-05T12:20:32.000+08:00
diff --git a/src/main/java/com/crossoverjie/actual/LRULinkedMap.java b/src/main/java/com/crossoverjie/actual/LRULinkedMap.java
@@ -0,0 +1,53 @@
+package com.crossoverjie.actual;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * Function:
+ *
+ * @author crossoverJie
+ *         Date: 05/04/2018 12:04
+ * @since JDK 1.8
+ */
+public class LRULinkedMap<K,V> {
+
+
+    /**
+     * 最大缓存大小
+     */
+    private int cacheSize;
+
+    private LinkedHashMap<K,V> cacheMap ;
+
+
+    public LRULinkedMap(int cacheSize) {
+        this.cacheSize = cacheSize;
+
+        cacheMap = new LinkedHashMap(16,0.75F,true){
+            @Override
+            protected boolean removeEldestEntry(Map.Entry eldest) {
+                if (cacheSize + 1 == cacheMap.size()){
+                    return true ;
+                }else {
+                    return false ;
+                }
+            }
+        };
+    }
+
+    public void put(K key,V value){
+        cacheMap.put(key,value) ;
+    }
+
+    public V get(K key){
+        return cacheMap.get(key) ;
+    }
+
+
+    public Collection<Map.Entry<K, V>> getAll() {
+        return new ArrayList<Map.Entry<K, V>>(cacheMap.entrySet());
+    }
+}
diff --git a/src/test/java/com/crossoverjie/actual/LRULinkedMapTest.java b/src/test/java/com/crossoverjie/actual/LRULinkedMapTest.java
@@ -0,0 +1,65 @@
+package com.crossoverjie.actual;
+
+import org.junit.Test;
+
+import java.util.Map;
+
+import static org.junit.Assert.*;
+
+public class LRULinkedMapTest {
+    @Test
+    public void put() throws Exception {
+        LRULinkedMap<String,Integer> map = new LRULinkedMap(3) ;
+        map.put("1",1);
+        map.put("2",2);
+        map.put("3",3);
+
+        for (Map.Entry<String, Integer> e : map.getAll()){
+            System.out.print(e.getKey() + " : " + e.getValue() + "\t");
+        }
+
+        System.out.println("");
+        map.put("4",4);
+        for (Map.Entry<String, Integer> e : map.getAll()){
+            System.out.print(e.getKey() + " : " + e.getValue() + "\t");
+        }
+    }
+
+    @Test
+    public void put2() throws Exception {
+        LRULinkedMap<String,Integer> map = new LRULinkedMap(4) ;
+        map.put("1",1);
+        map.put("2",2);
+        map.put("3",3);
+        map.put("4",4);
+
+        for (Map.Entry<String, Integer> e : map.getAll()){
+            System.out.print(e.getKey() + " : " + e.getValue() + "\t");
+        }
+
+        System.out.println("");
+        map.put("5",5);
+        for (Map.Entry<String, Integer> e : map.getAll()){
+            System.out.print(e.getKey() + " : " + e.getValue() + "\t");
+        }
+    }
+    @Test
+    public void get() throws Exception {
+        LRULinkedMap<String,Integer> map = new LRULinkedMap(4) ;
+        map.put("1",1);
+        map.put("2",2);
+        map.put("3",3);
+        map.put("4",4);
+
+        for (Map.Entry<String, Integer> e : map.getAll()){
+            System.out.print(e.getKey() + " : " + e.getValue() + "\t");
+        }
+
+        System.out.println("");
+        map.get("1") ;
+        for (Map.Entry<String, Integer> e : map.getAll()){
+            System.out.print(e.getKey() + " : " + e.getValue() + "\t");
+        }
+    }
+
+}
