Class Substring

    • Constructor Detail

      • Substring

        public Substring()
    • Method Detail

      • typeCheckCaller

        public Expression typeCheckCaller​(FunctionCall caller,
                                          ExpressionVisitor visitor,
                                          ContextItemStaticInfo contextInfo)
                                   throws XPathException
        Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.
        Overrides:
        typeCheckCaller in class SystemFunction
        Parameters:
        caller - the function call expression calling this function
        visitor - the expression visitor
        contextInfo - static context information relating to the call
        Returns:
        a type-checked replacement for the supplied function call
        Throws:
        XPathException - if an error is detected
      • substring

        public static StringValue substring​(StringValue sv,
                                            NumericValue start)
        Implement the substring function with two arguments.
        Parameters:
        sv - the string value
        start - the numeric offset (1-based) of the first character to be included in the result (if not an integer, the XPath rules apply)
        Returns:
        the substring starting at this position.
      • substring

        public static StringValue substring​(StringValue sv,
                                            NumericValue start,
                                            NumericValue len)
        Implement the substring function with three arguments.
        Parameters:
        sv - the string value
        start - the numeric offset (1-based) of the first character to be included in the result (if not an integer, the XPath rules apply)
        len - the length of the required substring (again, XPath rules apply)
        Returns:
        the substring starting at this position.
      • call

        public StringValue call​(XPathContext context,
                                Sequence[] arguments)
                         throws XPathException
        Evaluate the expression
        Specified by:
        call in interface Callable
        Parameters:
        context - the dynamic evaluation context
        arguments - the values of the arguments, supplied as Sequences
        Returns:
        the result of the evaluation, in the form of a Sequence
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the expression
      • getCompilerName

        public java.lang.String getCompilerName()
        Description copied from class: SystemFunction
        Get the (local) name of a class that can be used to generate bytecode for this system function
        Overrides:
        getCompilerName in class SystemFunction
        Returns:
        the name of a bytecode generation class, or null if there is no bytecode support for this function