Question

my Question is, is it possible to print out specific information from a class that provides no toString() method in JAVA?

There’s the rub: We provide a logger for our application (using aspectJ) which prints out the specific arguments, that were given. For example:

public void addGroupMembers(Group group, String doneBy, DataListModel<User> users) {
    doSomething()
}

And our Logger prints the following:

addGroupMembers called with given arguments:
Group = [id = ..... and so on]
username
DataListModel$1231 <-

We have to use the DataListModel-Class, because we’re working with JSF in the background. But, as you can see, this class doesn’t provide a toString method.

Our logger is written by ourself, so we can adapt that. Is it possible to simulate a toString method like: If the class doesn’t provide a toString, catch all their fields, and print them?

Or is there any other way?

Thanks in advance for your help.
Greetings, Thunderhook

Answer 1

You could make use of ReflectionToStringBuilder. Something like:

if (object.toString().endsWith("@" + Integer.toHexString(object.hashCode())) {
  // default toString()...
  return ReflectionToStringBuilder.toString(object);
}
else {
  return object.toString();
}