package com.brianway.learning.java8.lambda;

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.IOException;

/**

* Lambda实践: 环绕执行模式

* 1. 行为参数化

* 2. 使用函数式接口来传递行为

* 3. 执行一个行为

* 4. 传递 Lambda

*/

public class ExecuteAround {

private static final String RESOURCE_ROOT = ExecuteAround.class

.getResource("/").getPath() + "/data-lambda.txt";

public static void main(String... args) throws IOException {

// method we want to refactor to make more flexible

String result = processFileLimited();

System.out.println(result);

System.out.println("---");

String oneLine = processFile(BufferedReader::readLine);

System.out.println(oneLine);

String twoLines = processFile((BufferedReader b) -> b.readLine() + b.readLine());

System.out.println(twoLines);

}

public static String processFileLimited() throws IOException {

try (BufferedReader br =

new BufferedReader(new FileReader(RESOURCE_ROOT))) {

return br.readLine();

}

}

public static String processFile(BufferedReaderProcessor p) throws IOException {

try (BufferedReader br = new BufferedReader(new FileReader(RESOURCE_ROOT))) {

return p.process(br);

}

}

@FunctionalInterface

public interface BufferedReaderProcessor {

String process(BufferedReader b) throws IOException;

}

}