ThrowGenericException.java

// generics/ThrowGenericException.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
import java.util.*;

interface Processor<T, E extends Exception> {
  void process(List<T> resultCollector) throws E;
}

class ProcessRunner<T, E extends Exception>
extends ArrayList<Processor<T, E>> {
  List<T> processAll() throws E {
    List<T> resultCollector = new ArrayList<>();
    for(Processor<T, E> processor : this)
      processor.process(resultCollector);
    return resultCollector;
  }
}

class Failure1 extends Exception {}

class Processor1
implements Processor<String, Failure1> {
  static int count = 3;
  @Override
  public void process(List<String> resultCollector)
  throws Failure1 {
    if(count-- > 1)
      resultCollector.add("Hep!");
    else
      resultCollector.add("Ho!");
    if(count < 0)
       throw new Failure1();
  }
}

class Failure2 extends Exception {}

class Processor2
implements Processor<Integer, Failure2> {
  static int count = 2;
  @Override
  public void process(List<Integer> resultCollector)
  throws Failure2 {
    if(count-- == 0)
      resultCollector.add(47);
    else {
      resultCollector.add(11);
    }
    if(count < 0)
       throw new Failure2();
  }
}

public class ThrowGenericException {
  public static void main(String[] args) {
    ProcessRunner<String, Failure1> runner =
      new ProcessRunner<>();
    for(int i = 0; i < 3; i++)
      runner.add(new Processor1());
    try {
      System.out.println(runner.processAll());
    } catch(Failure1 e) {
      System.out.println(e);
    }

    ProcessRunner<Integer, Failure2> runner2 =
      new ProcessRunner<>();
    for(int i = 0; i < 3; i++)
      runner2.add(new Processor2());
    try {
      System.out.println(runner2.processAll());
    } catch(Failure2 e) {
      System.out.println(e);
    }
  }
}
/* Output:
[Hep!, Hep!, Ho!]
Failure2
*/