From: gumartinm <gu.martinm@gmail.com>
Date: Wed, 12 Oct 2011 18:22:15 +0000 (+0200)
Subject: Effective Java 2nd Edition:
X-Git-Url: https://git.gumartinm.name/?a=commitdiff_plain;h=3d7b4da19eebe30e8ca5ea1a82ac5bc44973166c;p=JavaForFun

Effective Java 2nd Edition:
Item 27

Change-Id: Idc2ff6e5e807e32961a9da4e7531b8133c7917c0
Signed-off-by: gumartinm <gu.martinm@gmail.com>
---

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..cc9a220
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+bin/
+.classpath
+.project
diff --git a/EffectiveJava2nd/Item27/src/test/GenericStaticFactory.java b/EffectiveJava2nd/Item27/src/test/GenericStaticFactory.java
new file mode 100644
index 0000000..74030dd
--- /dev/null
+++ b/EffectiveJava2nd/Item27/src/test/GenericStaticFactory.java
@@ -0,0 +1,24 @@
+package test;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class GenericStaticFactory {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		// Parameterized type instance creation with constructor
+		Map<String, List<String>> anagramsRedundancy = new HashMap<String, List<String>>();
+		
+		// Parameterized type instance creation with static factory. Without type parameters explicitly 
+		// when invoking generic constructors (it is annoying...)
+		Map<String, List<String>> anagrams = newHashMap();
+	}
+
+	public static <K,V> HashMap<K,V> newHashMap() {
+		return new HashMap<K,V>();
+	}
+}
diff --git a/EffectiveJava2nd/Item27/src/test/SingletonFactory.java b/EffectiveJava2nd/Item27/src/test/SingletonFactory.java
new file mode 100644
index 0000000..2b195eb
--- /dev/null
+++ b/EffectiveJava2nd/Item27/src/test/SingletonFactory.java
@@ -0,0 +1,39 @@
+/**
+ * 
+ */
+package test;
+
+/**
+ * @author gusarapo
+ *
+ */
+public class SingletonFactory {
+	
+	private static UnaryFunction<Object> IDENTITY_FUNCTION =
+			new UnaryFunction<Object>() {
+				public Object apply(Object arg)
+				{
+					return arg;
+				}
+	};	
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		String[] strings = {"jute", "hemp", "nylon"};
+		UnaryFunction<String> sameString = identityFunction();
+		for (String s : strings)
+			System.out.println(sameString.apply(s));
+		
+        Number [] numbers = {1, 2.0, 3L };
+		UnaryFunction<Number> sameNumber = identityFunction();
+		for (Number n : numbers)
+			System.out.println(sameNumber.apply(n));
+	}
+	
+	@SuppressWarnings("unchecked")
+	public static <T> UnaryFunction<T> identityFunction() {
+		return (UnaryFunction<T>) IDENTITY_FUNCTION;
+	}
+
+}
diff --git a/EffectiveJava2nd/Item27/src/test/UnaryFunction.java b/EffectiveJava2nd/Item27/src/test/UnaryFunction.java
new file mode 100644
index 0000000..e212f1e
--- /dev/null
+++ b/EffectiveJava2nd/Item27/src/test/UnaryFunction.java
@@ -0,0 +1,12 @@
+/**
+ * 
+ */
+package test;
+
+/**
+ * @author gustavo
+ *
+ */
+public interface UnaryFunction<T> {
+	T apply (T arg);
+}