Java新特性解读JDK8之函数式接口Predicate

package java.util.function;


import java.util.Objects;


/**
 * Represents a predicate (boolean-valued function) of one argument.
 *
 * <p>This is a <a href="package-summary.html">functional interface</a>
 * whose functional method is {@link #test(Object)}.
 *
 * @param <T> the type of the input to the predicate
 *
 * @since 1.8
 */
@FunctionalInterface
public interface Predicate<T> {


    /**
     * Evaluates this predicate on the given argument.
     *
     * @param t the input argument
     * @return {@code true} if the input argument matches the predicate,
     * otherwise {@code false}
     */
    boolean test(T t);
    }
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package com.example.functionalinterfacedemo;


import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;


public class PredicateDemo {
  public static void main(String[] args) {
    List<Integer> asList = Arrays.asList(1,2,3,4,5,6,7,8,9);
    List<Integer> list = test(asList, obj->obj.intValue()>5);
    System.out.println(list);
  }


  /**
   * 
   * @param list 接受参数
   * @param predicate 定义函数
   * @return 满足一定条件的数据
   */
  public static List<Integer> test(List<Integer> list,Predicate<Integer> predicate){
    List<Integer> list2=new ArrayList<Integer>();
    for(Integer integer :list ){
      if(predicate.test(integer)){
        list2.add(integer);
      }
    }
    return list2;
    
  }
}


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