package threadPool;

import java.io.*;

import java.util.*;

import java.util.concurrent.*;

public class ThreadPoolTest {

public static void main(String[] args) throws Exception{

// TODO Auto-generated method stub

Scanner in=new Scanner(System.in);

System.out.print("Enter base directory(e.g. /usr/local/jdk5.0/src):");

String directory=in.next();

System.out.print("Enter keyword (e.g. volatile):");

String keyword=in.next();

System.out.println("keyword:"+keyword+"directory:"+directory);

ExecutorService pool=Executors.newCachedThreadPool();

MatchCounter counter=new MatchCounter(new File(directory),keyword,pool);

Future<Integer> result=pool.submit(counter);

try{

System.out.println(result.get()+"matching files");

}catch(ExecutionException e){

e.printStackTrace();

}catch(InterruptedException e){

}

pool.shutdown();

int largestPoolSize=((ThreadPoolExecutor) pool).getLargestPoolSize();

System.out.println("largest pool size="+largestPoolSize);

}

}

class MatchCounter implements Callable<Integer>{

private File directory;

private String keyword;

private ExecutorService pool;

private int count;

public MatchCounter(File directory,String keyword,ExecutorService pool){

this.directory=directory;

this.keyword=keyword;

this.pool=pool;

}

public Integer call(){

count=0;

try {

File[] files=directory.listFiles();

List<Future<Integer>> results=new ArrayList<>();

for(File file:files)

if(file.isDirectory()){

MatchCounter counter=new MatchCounter(file,keyword,pool);

Future<Integer> result=pool.submit(counter);

results.add(result);

}

else{

if(search(file)) count++;

}

for(Future<Integer> result:results)

try {

count+=result.get();

} catch (ExecutionException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return count;

}

public boolean search(File file){

try{

try(Scanner in=new Scanner(file)){

boolean found=false;

while(!found&&in.hasNext()){

String line=in.nextLine();

if(line.contains(keyword))

found=true;

}

return found;

}

}catch(IOException e){

return false;

}

}

}