Java 8 : Function

What is a Function?

This is a predefined functional interface like Predicate, present in java.util.function package. It has one abstract method called apply();

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interface Function<T,R> { public R apply(T t); }

Function example 1: to check the length of the string.

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package com.blogspot.ekumeedkiasha; import java.util.function.Function; public class FunctionExample1 { public static void main(String[] args) { Function<String, Integer> fun = s -> s.length(); System.out.println(fun.apply("ekumeedhelp")); } }

Function Chaining example:

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package com.blogspot.ekumeedkiasha; import java.util.function.Function; public class FunctionChaining { public static void main(String[] args) { int amount = 3; Function<Integer, Integer> sum = i -> i + i; // 3 + 3 = 6 Function<Integer, Integer> sq = i -> i * i; // 6 * 6 = 36 System.out.println(sum.apply(amount)); System.out.println(sq.apply(amount)); System.out.println(sum.andThen(sq).apply(amount)); System.out.println(sum.compose(sq).apply(amount)); } }

 

Author : Ekumeed Help

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