Extending an ANTLR 4 visitor class to allow "hooking" execution with a ParseTreeListener

FooVisitor.java

// the main visitor implementation
class FooVisitor extends SomeBaseVisitor<T> {

}

// extend the visitor with hooks for a listener
class FooListenerVisitor extends FooVisitor {
    private ParseTreeListener listener;

    public FooListenerVisitor(ParseTreeListener listener) {
        this.listener = listener;
    }

    @Override
    public T visit(ParseTree tree) {
        try {
            if (listener != null) {
                if (tree instanceof ParserRuleContext) {
                    ((ParserRuleContext)tree).enterRule(listener);
                }
                else if (tree instanceof ErrorNode) {
                    listener.visitErrorNode((ErrorNode)tree);
                }
                else if (tree instanceof TerminalNode) {
                    listener.visitTerminal((TerminalNode)tree);
                }
            }

            return super.visit(tree);
        }
        finally {
            if (listener != null) {
                if (tree instanceof ParserRuleContext) {
                    ((ParserRuleContext)tree).exitRule(listener);
                }
            }
        }
    }

    @Override
    public T visitChildren(RuleNode node) {
        // do whatever here
        return super.visitChildren(node);
    }
}