Catch the attributes of a Thread object?

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Is it possible to get the attributes of a Thread object? because I am using threads to read several files (one per thread) (which has float numbers separated by \ n) storing the floats do the sum of floats and doing the average of values, but it is necessary to do a general sum of the files but I can not get the generated values within the thread by the main class.

Main class: 

package multithread;

import java.util.ArrayList;
import java.util.List;

public class MultiThread {

public static void main(String[] args) {
    List<String> pathsCemMil = new ArrayList<String>();
    pathsCemMil.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatCemMil_A.txt");
    pathsCemMil.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatCemMil_B.txt");
    pathsCemMil.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatCemMil_C.txt");

    List<String> pathsDezMil = new ArrayList<String>();
    pathsDezMil.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatDezMil_A.txt");
    pathsDezMil.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatDezMil_B.txt");
    pathsDezMil.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatDezMil_C.txt");

    List<String> pathsUmMilhao = new ArrayList<String>();
    pathsUmMilhao.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatUmMilhao_A.txt");
    pathsUmMilhao.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatUmMilhao_B.txt");
    pathsUmMilhao.add("C:\Users\Ricardo\Documents\NetBeansProjects\MultiThread\src\arquivos\NumerosFloatUmMilhao_C.txt");

    List<Thread> threadsDezMil = new ArrayList<Thread>();
    for(String path : pathsDezMil){
        threadsDezMil.add(new Worker(path));

    }

    List<Thread> threadsCemMil = new ArrayList<Thread>();
    for(String path : pathsCemMil){
        new Worker(path).start();
    }

    List<Thread> threadsUmMilhao = new ArrayList<Thread>();
    for(String path : pathsUmMilhao){
        new Worker(path).start();
    }
}

}

Thread class: 

package multithread;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Worker extends Thread{
String path;
double valoresSoma;
double valoresMedia;
int valoresAcimaMedia;

public Worker(String path){
    this.path = path;
}

public void run(){
    try {
        List<Double> valores = new ArrayList<Double>();
        valores = reader(this.path);
        valoresSoma = soma(valores);
        valoresMedia = media(valoresSoma,valores.size());
        valoresAcimaMedia = acimaMedia(valores, valoresMedia);
        System.out.println(this.path);
        System.out.println(valores.size());
        System.out.println(valoresSoma);
        System.out.println(valoresMedia);
        System.out.println(valoresAcimaMedia);
    } catch (IOException ex) {
        Logger.getLogger(Worker.class.getName()).log(Level.SEVERE, null, ex);
    }
}
public static List<Double> reader(String path) throws IOException{
    List<Double> valores = new ArrayList<>();
    FileReader fileReader = new FileReader(path);
    BufferedReader reader = new BufferedReader(fileReader);
    String data = null;
    while((data = reader.readLine()) != null){
        valores.add(Double.parseDouble(data)); 
    }
    fileReader.close();
    reader.close();
    return valores;
}

public static double soma(List<Double> valores){
    double soma = 0;
    for(Double valor : valores){
        soma += valor;
    }
    return soma;
}

public static double media(double soma, int qtde){
    return soma/qtde;
}

public static int acimaMedia(List<Double> valores, double media){
    int qtde = 0;
    for(Double valor : valores){
        if(valor > media){
            qtde++;
        }
    }
    return qtde;
}
}

Sample file that has float values: 

898.29
653.46
572.77
669.53
695.89
400.91
392.73
547.55
748.77
38.43
    
asked by anonymous 20.04.2015 / 18:17

1 answer

1

It is possible to retrieve information from objects normally, however you need to wait for threads to stop executing before attempting to do this.

If you want to do it by hand, use the basic synchronization commands of Java wait and notify .

However, there is a much easier API for working with threads and synchronization, ThreadPoolExecutor .

See the simple example I made:

Thread 

public class Worker implements Runnable {

    int soma;

    public void run() {
        //executa operações complexas
        soma = new Random().nextInt();
    }

    public int getSoma() {
        return soma;
    }

}

Manager code 

//cria pool de threads para execução de tarefas
ThreadPoolExecutor p = new ThreadPoolExecutor(5, 10, 1, TimeUnit.HOURS, new ArrayBlockingQueue<Runnable>(10));

//cria threads com tarefas a executar
Worker w1 = new Worker(); 
Worker w2 = new Worker(); 
Worker w3 = new Worker();

//submete tarefas para a execução
p.submit(w1);
p.submit(w2);
p.submit(w3);

//força a execução e finalização das threads
p.shutdown();

//aguarda finalização das threads em execução
p.awaitTermination(1, TimeUnit.DAYS);

//recupera resultados parciais e exibe
int soma = w1.getSoma() + w2.getSoma() + w3.getSoma();
System.out.println("Soma = " + soma);
    
20.04.2015 / 20:58
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