add flyweight DP

src/designpattern/flyweight/FlyWeight.java

@@ -0,0 +1,31 @@
+package designpattern.flyweight;
+
+/**
+ * 所有具体享元类的超类，接受并作用于外部状态
+ * 
+ * @author liu yuning
+ *
+ */
+public abstract class FlyWeight {
+
+    public abstract void operation(int extrinsicState);
+
+}
+
+class ConcreteFlyWeight extends FlyWeight {
+
+    @Override
+    public void operation(int extrinsicState) {
+	System.out.println("具体FlyWeight：" + extrinsicState);
+    }
+
+}
+
+class UnsharedConcreteFlyWeight extends FlyWeight {
+
+    @Override
+    public void operation(int extrinsicState) {
+	System.out.println("不共享的具体FlyWeight：" + extrinsicState);
+    }
+
+}

src/designpattern/flyweight/FlyWeightClient.java

@@ -0,0 +1,29 @@
+package designpattern.flyweight;
+
+/**
+ * 客户端
+ * 
+ * @author liu yuning
+ *
+ */
+public class FlyWeightClient {
+    public static void main(String[] args) {
+	int extrinsicState = 22;
+
+	FlyWeightFactory f = new FlyWeightFactory();
+
+	FlyWeight fx = f.getFlyWeight("X");
+	fx.operation(--extrinsicState);
+
+	FlyWeight fy = f.getFlyWeight("Y");
+	fy.operation(--extrinsicState);
+
+	FlyWeight fz = f.getFlyWeight("Z");
+	fz.operation(--extrinsicState);
+
+	FlyWeight uf = new UnsharedConcreteFlyWeight();
+	uf.operation(--extrinsicState);
+
+    }
+
+}

src/designpattern/flyweight/FlyWeightFactory.java

@@ -0,0 +1,22 @@
+package designpattern.flyweight;
+
+import java.util.HashMap;
+
+/**
+ * 享元工厂
+ * 
+ * @author liu yuning
+ *
+ */
+public class FlyWeightFactory {
+    private HashMap<String, FlyWeight> flyWeights = new HashMap<String, FlyWeight>();
+
+    public FlyWeight getFlyWeight(String key) {
+	if (!flyWeights.containsKey(key)) {
+	    flyWeights.put(key, new ConcreteFlyWeight());
+	}
+
+	return flyWeights.get(key);
+    }
+
+}