private void removeMapping ( int num ) { if ( num < numMappings ) { System . arraycopy ( mappings , num * 2 , mappings , ( num - 1 ) * 2 , ( numMappings - num ) * 2 ) ; } mappings [ numMappings * 2 - 1 ] = null ; mappings [ numMappings * 2 - 2 ] = null ; numMappings -- ; }
num ranges from 1 to numMappings