Class CountCompiler


  • public class CountCompiler
    extends ToItemCompiler
    Generate bytecode for a call to the count() function
    • Constructor Detail

      • CountCompiler

        public CountCompiler()
    • Method Detail

      • compileToPrimitive

        public void compileToPrimitive​(CompilerService compiler,
                                       Expression expression,
                                       java.lang.Class requiredClass,
                                       OnEmpty onEmpty)
                                throws CannotCompileException
        Description copied from class: ExpressionCompiler
        Generate bytecode to evaluate the expression leaving a plain Java value on the stack. This method must only be called if the static type of the expressionis such that the value is known to be representable by a value of the specified class; the cardinality must be either exactly-one or zero-or-one.
        Overrides:
        compileToPrimitive in class ExpressionCompiler
        Parameters:
        compiler - the compiler service
        expression - the expression to be compiled
        requiredClass - the class of the Java value that is to be left on the stack if the generated code exits normally. This must be one of Integer.TYPE, Double.TYPE, Float.TYPE, BigDecimal.class, String.class, UnicodeString.class.
        onEmpty - defines the action to be taken if the expression evaluates to the empty sequence. May be null if the expression is known statically not to evaluate to an empty sequence. If the return class is a primitive type (double, float, etc) this must be an instance of OnEmpty.UnwindAndJump
        Throws:
        CannotCompileException - if the expression cannot be compiled to bytecode
      • compileToItem

        public void compileToItem​(CompilerService compiler,
                                  Expression expression)
                           throws CannotCompileException
        Generate bytecode to evaluate the expression as an Item Precondition: none. Postcondition: the stack contains either an item (the result of the expression), or null (representing an empty sequence).
        Specified by:
        compileToItem in class ExpressionCompiler
        Parameters:
        compiler - the compiler service
        expression - the expression to be compiled
        Throws:
        CannotCompileException - if the expression cannot be compiled to bytecode
      • maybeLastPositionFinder

        public static boolean maybeLastPositionFinder​(Expression expression)