enum approach of singleton

yejinchang · yejinchang · commit 13abf4902495 · 2014-11-24T17:35:52.000+08:00
diff --git a/singleton/src/main/java/com/iluwatar/App.java b/singleton/src/main/java/com/iluwatar/App.java
@@ -22,5 +22,9 @@ public static void main(String[] args) {
 		System.out.println("threadSafeIvoryTower1=" + threadSafeIvoryTower1);
 		System.out.println("threadSafeIvoryTower2=" + threadSafeIvoryTower2);
 
+		EnumIvoryTower enumIvoryTower1 = EnumIvoryTower.getInstance();
+		EnumIvoryTower enumIvoryTower2 = EnumIvoryTower.getInstance();
+		System.out.println("enumIvoryTower1=" + enumIvoryTower1.getDeclaringClass().getCanonicalName() + "@" + enumIvoryTower1.hashCode());
+		System.out.println("enumIvoryTower2=" + enumIvoryTower2.getDeclaringClass().getCanonicalName() + "@" + enumIvoryTower2.hashCode());
 	}
 }
diff --git a/singleton/src/main/java/com/iluwatar/EnumIvoryTower.java b/singleton/src/main/java/com/iluwatar/EnumIvoryTower.java
@@ -0,0 +1,14 @@
+package com.iluwatar;
+
+/**
+ *
+ * Enum Singleton class.
+ *
+ */
+public enum EnumIvoryTower {
+    INSTANCE;
+
+    public static EnumIvoryTower getInstance() {
+        return INSTANCE;
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -22,5 +22,9 @@ public static void main(String[] args) {`
`22`	`22`	`System.out.println("threadSafeIvoryTower1=" + threadSafeIvoryTower1);`
`23`	`23`	`System.out.println("threadSafeIvoryTower2=" + threadSafeIvoryTower2);`
`24`	`24`
	`25`	`+ EnumIvoryTower enumIvoryTower1 = EnumIvoryTower.getInstance();`
	`26`	`+ EnumIvoryTower enumIvoryTower2 = EnumIvoryTower.getInstance();`
	`27`	`+ System.out.println("enumIvoryTower1=" + enumIvoryTower1.getDeclaringClass().getCanonicalName() + "@" + enumIvoryTower1.hashCode());`
	`28`	`+ System.out.println("enumIvoryTower2=" + enumIvoryTower2.getDeclaringClass().getCanonicalName() + "@" + enumIvoryTower2.hashCode());`
`25`	`29`	`}`
`26`	`30`	`}`