54 lines
1.1 KiB
Java
54 lines
1.1 KiB
Java
// functional/MethodReferences.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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import java.util.*;
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interface Callable { // [1]
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void call(String s);
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}
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class Describe {
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void show(String msg) { // [2]
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System.out.println(msg);
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}
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}
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public class MethodReferences {
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static void hello(String name) { // [3]
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System.out.println("Hello, " + name);
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}
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static class Description {
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String about;
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Description(String desc) { about = desc; }
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void help(String msg) { // [4]
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System.out.println(about + " " + msg);
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}
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}
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static class Helper {
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static void assist(String msg) { // [5]
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System.out.println(msg);
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}
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}
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public static void main(String[] args) {
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Describe d = new Describe();
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Callable c = d::show; // [6]
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c.call("call()"); // [7]
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c = MethodReferences::hello; // [8]
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c.call("Bob");
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c = new Description("valuable")::help; // [9]
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c.call("information");
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c = Helper::assist; // [10]
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c.call("Help!");
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}
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}
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/* Output:
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call()
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Hello, Bob
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valuable information
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Help!
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*/
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