Is it possible to make a Spring ApplicationListener listen for 2 or more types of events?

Question

I\'ve got 2 different types of events that I want my class to be able to listen for and process accordingly (and differently).

I tried: public class Listener

Answer 1

Spring < 4.2

A little more elegant than instanceof or static class is the visitor pattern. I think the visitor pattern provides a very useful alternative to that shortcoming of older Spring.

public class ListenerClass implements ApplicationListener, FooBarVisitor {
    @Override
    public void onApplicationEvent(FooBarBase fooBarBase) {
        fooBarBase.accept(this);
    }

    @Override
    public void visitFoo(Foo foo) {
        System.out.println("Handling Foo Event...");
    }

    @Override
    public void visitBar(Bar bar) {
        System.out.println("Handling Bar Event...");
    }
}

public interface FooBarVisitor {
    void visitFoo(Foo foo);
    void visitBar(Bar bar);
}

public abstract class FooBarBase extends ApplicationEvent {
    public FooBarBase(Object source) {
        super(source);
    }

    abstract void accept(FooBarVisitor visitor);
}

public class Bar extends FooBarBase {
    public Bar(Object source) {
        super(source);
    }

    @Override
    void accept(FooBarVisitor visitor) {
        visitor.visitBar(this);
    }
}

public class Foo extends FooBarBase {
    public Foo(Object source) {
        super(source);
    }

    @Override
    void accept(FooBarVisitor visitor) {
        visitor.visitFoo(this);
    }
}