Java Blog

Today I browsed through Project Coin and had a closer look at the language changes that made it into Java 7. Especially the proposal named ‘Improved Type Inference for Generic Instance Creation’ attracted my attention, because I already discovered a technique in Joshua Bloch’s great book Effective Java (2nd Edition) that helped me to reduce the effort to create Generics.
All you need is a Factory-class with static methods:

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package com.java_blog.generics;
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import java.util.HashMap;
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public class GenericsFactory {
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	public static <K, V> HashMap<K, V> newHashMap() {
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		return new HashMap<K, V>();
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	}
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}

If you import these methods statically into your code, Generics-creation becomes very handy:

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package com.java_blog.generics;
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import java.util.HashMap;
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import static com.java_blog.generics.GenericsFactory.newHashMap;
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public class GenericsTest {
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	public static void main(String[] args) {
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		// old style
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		HashMap<String, Integer> oldMap = new HashMap<String, Integer>();
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		// new style
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		HashMap<String, Integer> newMap = newHashMap();
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	}
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}

Happy Coding,
Tino

tino Java Generics, Java