question: public Buffer create ( int level ) { if ( ! canCreate ( ) ) { return null ; } Buffer buffer = new Buffer ( bufferSize , level , randomGenerator ) ; List < Buffer > bufferList = bufferMap . get ( level ) ; if ( bufferList == null ) { bufferList = new ArrayList < Buffer > ( ) ; bufferMap . put ( level , bufferList ) ; } bufferList . add ( buffer ) ; count ++ ; if ( level > maxLevel ) { maxLevel = level ; } return buffer ; }
target:  Tries to create a buffer with the given level. <p> If there is capacity to create a new buffer (i.e., fewer than count have been created), a new buffer is created with the given level, registered and returned.  If capacity has been reached, null is returned.