Balking

Origin:

Lea 97

Reason:

Disregard the call to a method of an object, if the state of the object is not appropriate to execute the call.

Synopsis:

Test the object's state, in a synchronized block for thread safety, and return if the state is inappropriate.

Example:

A toilet with an automatic flusher should not begin a flush cycle when another cycle is in progress.

Solution:

In its simplest form, the potentially balking method looks like:

void balkingMethod () {
    synchronized (this) {
        if (! some_condition) return;
        else 
            ... // code possibly changing some_condition
    }
    ... // do whatever
}

The synchronized block ensures thread safety.