66 lines
1.7 KiB
Java
66 lines
1.7 KiB
Java
// generics/LatentReflection.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://OnJava8.com for more book information.
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// Using reflection for latent typing
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import java.lang.reflect.*;
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// Does not implement Performs:
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class Mime {
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public void walkAgainstTheWind() {}
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public void sit() {
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System.out.println("Pretending to sit");
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}
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public void pushInvisibleWalls() {}
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@Override
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public String toString() { return "Mime"; }
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}
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// Does not implement Performs:
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class SmartDog {
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public void speak() { System.out.println("Woof!"); }
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public void sit() { System.out.println("Sitting"); }
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public void reproduce() {}
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}
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class CommunicateReflectively {
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public static void perform(Object speaker) {
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Class<?> spkr = speaker.getClass();
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try {
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try {
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Method speak = spkr.getMethod("speak");
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speak.invoke(speaker);
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} catch(NoSuchMethodException e) {
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System.out.println(speaker + " cannot speak");
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}
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try {
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Method sit = spkr.getMethod("sit");
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sit.invoke(speaker);
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} catch(NoSuchMethodException e) {
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System.out.println(speaker + " cannot sit");
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}
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} catch(SecurityException |
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IllegalAccessException |
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IllegalArgumentException |
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InvocationTargetException e) {
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throw new RuntimeException(speaker.toString(), e);
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}
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}
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}
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public class LatentReflection {
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public static void main(String[] args) {
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CommunicateReflectively.perform(new SmartDog());
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CommunicateReflectively.perform(new Robot());
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CommunicateReflectively.perform(new Mime());
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}
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}
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/* Output:
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Woof!
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Sitting
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Click!
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Clank!
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Mime cannot speak
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Pretending to sit
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*/
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