策略模式(回调函数)

/**
 * 
 */
package com.zachary.io.util;

import java.io.File;
import java.io.IOException;

/**
 * @author Zachary.Zheng
 * @version 1.0
 * @date 2019年11月9日
 */
public class ProcessFiles {
	/**
	 * 定义回调函数接口
	 * 在调用时实现
	 * @author Zachary.Zheng
	 * @version 1.0
	 * @date 2019年11月9日
	 */
	public interface Strategy{
		void process(File file);
	}
	private Strategy strategy;
	private String ext;
	public ProcessFiles(Strategy strategy, String ext) {
		super();
		this.strategy = strategy;
		this.ext = ext;
	}
	public ProcessFiles() {
		super();
	}

	public void start(String [] args) {
		try {
			if(args.length == 0) {
				processDirectoryTree(new File("."));
			} else {
				for (String arg : args) {
					File fileArg = new File(arg);
					if(fileArg.isDirectory()) {
						processDirectoryTree(fileArg);
					} else {
						if(!arg.endsWith("." + ext)) {
							arg += "." + ext;
						}
						// 执行回调函数
						strategy.process(new File(arg).getCanonicalFile());
					}
				}
			}
		} catch (Exception e) {
			// TODO: handle exception
		}
	}
	public void processDirectoryTree(File root) throws IOException {
		for(File file: Directory.walk(root.getAbsolutePath(), ".*\."+ext)) {
			// 执行回调函数
			strategy.process(file.getCanonicalFile());
		}
	}
	public static void main(String[] args) {
		new ProcessFiles(new ProcessFiles.Strategy() {
			// 回调函数
			public void process(File file) {
				System.out.println(file);
			}
		}, "java").start(args);;
	}
}
/* Output: (sample)
E:\javaBaseLearn\IOStreamworkSpace\java-io-stream\src\com\zachary\io\util\Directory.java
E:\javaBaseLearn\IOStream\workSpace\java-io-stream\src\com\zachary\io\util\DirList.java
E:\javaBaseLearn\IOStream\workSpace\java-io-stream\src\com\zachary\io\util\DirList2.java
E:\javaBaseLearn\IOStream\workSpace\java-io-stream\src\com\zachary\io\util\DirList3.java
E:\javaBaseLearn\IOStream\workSpace\java-io-stream\src\com\zachary\io\util\PPrint.java
E:\javaBaseLearn\IOStream\workSpace\java-io-stream\src\com\zachary\io\util\ProcessFiles.java
E:\javaBaseLearn\IOStream\workSpace\java-io-stream\src\com\zachary\io\util\TreeInfo.java 
*///:~