I have a arraylist which consists of 5000 IP Addresses. For each IP Address, I want to execute a SNMPGet request and a FTPDownload command. I want to implement it in a fashion,
Herewith adding working example having 5 threads. Just put the test.txt in your CLASS_PATH of the application.
class MyRunnable implements Runnable {
List<List<String>> records;
MyRunnable(List<List<String>> records){
this.records = records;
}
public void run(){
for(List list : records){
System.out.println(Thread.currentThread().getName() + " : "+list.toString());
}
}}
Main Class -
public class FileProcessThreads {
public List<List<String>> process(String fileName) throws IOException {
List<List<String>> records = new ArrayList<>();
BufferedReader br = new BufferedReader(new FileReader(fileName));
String line = null;
while((line = br.readLine()) != null){
List<String> listValues = Arrays.asList(line.split(" "));
records.add(listValues);
}
System.out.println(records.size());
return records;
}
public static void main(String[] args) throws IOException {
FileProcessThreads fp = new FileProcessThreads();
List<List<String>> records = fp.process("test.txt");
ExecutorService es = Executors.newFixedThreadPool(5);
int recordsInEachThread = (int) (records.size()/5);
System.out.println(recordsInEachThread);
MyRunnable my1 = new MyRunnable(records.subList(0, recordsInEachThread));
MyRunnable my2 = new MyRunnable(records.subList(recordsInEachThread+1, recordsInEachThread*2));
MyRunnable my3 = new MyRunnable(records.subList(recordsInEachThread*2 + 1, recordsInEachThread*3));
MyRunnable my4 = new MyRunnable(records.subList(recordsInEachThread*3 + 1, recordsInEachThread*4));
MyRunnable my5 = new MyRunnable(records.subList(recordsInEachThread*4 + 1, records.size() - 1));
es.execute(my1);
es.execute(my2);
es.execute(my3);
es.execute(my4);
es.execute(my5);
es.shutdown();
}}
Executor Framework will be best suit for your solution. I have created one example here. You can increase the number of threads as per your requirement.
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
class SomeRunnable implements Runnable {
int threadNo = -1 ;
List<String> list = new ArrayList<String>();
public SomeRunnable(List list, int threadNo ) {
this.list.addAll(list);
this.threadNo =threadNo;
}
@Override
public void run() {
for (String element : list) {
System.out.println("By Thread:" + threadNo+", Processed Element:" +element);
}
}
}
public class ExecutorDemo {
public static void main(String[] args) {
List<String> list = new ArrayList<String>();
for (int i = 0; i < 100; i++) {
list.add("Elem:"+i);
}
// Divide list
int divideIndex = list.size()/2;
//Create objects of Runnable
SomeRunnable obj1 = new SomeRunnable(list.subList(0, divideIndex),1);
SomeRunnable obj2 = new SomeRunnable(list.subList(divideIndex,list.size()),2);
//Create fixed Thread pool, here pool of 2 thread will created
ExecutorService pool = Executors.newFixedThreadPool(2);
pool.execute(obj1);
pool.execute(obj2);
pool.shutdown();
}
}