46 lines
1.1 KiB
Java
46 lines
1.1 KiB
Java
// generics/InstantiateGenericType.java
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// (c)2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
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import java.util.function.*;
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class ClassAsFactory<T> implements Supplier<T> {
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Class<T> kind;
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public ClassAsFactory(Class<T> kind) {
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this.kind = kind;
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}
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@Override
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public T get() {
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try {
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return kind.newInstance();
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} catch(InstantiationException |
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IllegalAccessException e) {
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throw new RuntimeException(e);
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}
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}
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}
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class Employee {
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@Override
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public String toString() { return "Employee"; }
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}
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public class InstantiateGenericType {
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public static void main(String[] args) {
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ClassAsFactory<Employee> fe =
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new ClassAsFactory<>(Employee.class);
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System.out.println(fe.get());
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ClassAsFactory<Integer> fi =
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new ClassAsFactory<>(Integer.class);
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try {
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System.out.println(fi.get());
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} catch(Exception e) {
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System.out.println(e.getMessage());
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}
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}
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}
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/* Output:
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Employee
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java.lang.InstantiationException: java.lang.Integer
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*/
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