70 lines
1.6 KiB
Java
70 lines
1.6 KiB
Java
// typeinfo/SelectingMethods.java
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// (c)2020 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://OnJava8.com for more book information.
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// Looking for particular methods in a dynamic proxy
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import java.lang.reflect.*;
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class MethodSelector implements InvocationHandler {
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private Object proxied;
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MethodSelector(Object proxied) {
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this.proxied = proxied;
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}
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@Override
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public Object
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invoke(Object proxy, Method method, Object[] args)
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throws Throwable {
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if(method.getName().equals("interesting"))
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System.out.println(
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"Proxy detected the interesting method");
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return method.invoke(proxied, args);
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}
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}
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interface SomeMethods {
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void boring1();
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void boring2();
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void interesting(String arg);
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void boring3();
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}
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class Implementation implements SomeMethods {
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@Override
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public void boring1() {
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System.out.println("boring1");
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}
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@Override
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public void boring2() {
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System.out.println("boring2");
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}
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@Override
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public void interesting(String arg) {
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System.out.println("interesting " + arg);
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}
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@Override
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public void boring3() {
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System.out.println("boring3");
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}
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}
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class SelectingMethods {
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public static void main(String[] args) {
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SomeMethods proxy =
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(SomeMethods)Proxy.newProxyInstance(
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SomeMethods.class.getClassLoader(),
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new Class[]{ SomeMethods.class },
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new MethodSelector(new Implementation()));
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proxy.boring1();
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proxy.boring2();
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proxy.interesting("bonobo");
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proxy.boring3();
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}
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}
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/* Output:
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boring1
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boring2
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Proxy detected the interesting method
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interesting bonobo
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boring3
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*/
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