Question

I’m trying to do something like this:

 public void <String,int> getItem
 { 
   return <"Jen",23>;
 }

I know I can use a custom class, but how I would I return two results in one function call.

1 – Is the above template function possible in java, and how would by caller get part 1 of it and part 2 later.

2 – Can I do it using an associative array like in actionscript?

3 – Can I do it using a hashmap of some sort?

4 – What are other possible ways are there

I attempted all three ways, but one way or another syntax is hitting me. So if anyone can give clear examples

Answer 1

Java functions always return a single value, so your only option is to return a “collection” object which contains multiple values, such as an Array or a proper Collection. For example:

public Object[] getItem() { return new Object[] { "Jen", 23 }; }
public Collection<Object> { return Arrays.asList("Jen", 23); }

Although, a typical pattern in Java is to return a custom type which encapsulates your values, e.g.:

public class NameAge {
  public final String name;
  public final int age;
  public NameAge(String name, int age) {
    this.name = name;
    this.age = age;
  }
}
// ...
public NameAge getItem() { return new NameAge("Jen", 23); }

Or more generally:

public class Pair<X, Y> {
  public final X x;
  public final Y y;
  public Pair(X x, Y y) {
    this.x = x;
    this.y = y;
  }
}
// ...
public Pair<String,Integer> getItem() {
  return new Pair<String,Integer>("Jen", 23);
}

Of course, there are serious implications regarding hashing (equality and hash code) if you want to use these custom types as hash keys.