30 lines
762 B
Java
30 lines
762 B
Java
// generics/CaptureConversion.java
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// ©2015 MindView LLC: see Copyright.txt
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public class CaptureConversion {
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static <T> void f1(Holder<T> holder) {
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T t = holder.get();
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System.out.println(t.getClass().getSimpleName());
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}
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static void f2(Holder<?> holder) {
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f1(holder); // Call with captured type
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}
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@SuppressWarnings("unchecked")
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public static void main(String[] args) {
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Holder raw = new Holder<>(1);
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// f1(raw); // Produces warnings
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f2(raw); // No warnings
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Holder rawBasic = new Holder();
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rawBasic.set(new Object()); // Warning
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f2(rawBasic); // No warnings
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// Upcast to Holder<?>, still figures it out:
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Holder<?> wildcarded = new Holder<>(1.0);
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f2(wildcarded);
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}
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}
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/* Output:
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Integer
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Object
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Double
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*/
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