question: private synchronized void block ( boolean tf ) { if ( tf ) { try { if ( m_evaluateThread != null && m_evaluateThread . isAlive ( ) ) { wait ( ) ; } } catch ( InterruptedException ex ) { } } else { notifyAll ( ) ; } }
target:  Function used to stop code that calls acceptClusterer. This is needed as clusterer evaluation is performed inside a separate thread of execution.