question: @ Override public String toString ( ) { String str = "" ; for ( String q : queryVars ) { str += q + "," ; } if ( ! queryVars . isEmpty ( ) ) { str = str . substring ( 0 , str . length ( ) - 1 ) ; } if ( ! evidence . isEmpty ( ) ) { str += "|" ; if ( ! evidence . isEmpty ( ) ) { str += evidence ; } } str += "" ; if ( this instanceof ProbQuery ) { return "P(" + str + ")" ; } else if ( this instanceof UtilQuery ) { return "U(" + str + ")" ; } else { return "Reduce(" + str + ")" ; } }
target:  Returns a string representation of the query.