Class ErrorExpression


  • public class ErrorExpression
    extends Expression
    Error expression: this expression is generated when the supplied expression cannot be parsed, and the containing element enables forwards-compatible processing. It defers the generation of an error message until an attempt is made to evaluate the expression
    • Constructor Detail

      • ErrorExpression

        public ErrorExpression​(XPathException exception)
        Constructor
        Parameters:
        exception - the error found when parsing this expression
    • Method Detail

      • evaluate

        public Value evaluate​(Context c)
                       throws XPathException
        Evaluate this expression. This always throws the exception registered when the expression was first parsed.
        Specified by:
        evaluate in class Expression
        Parameters:
        c - The context in which the expression is to be evaluated
        Returns:
        the value of the expression, evaluated in the current context
        Throws:
        XPathException
      • getDataType

        public int getDataType()
        Determine the data type of the expression, if possible
        Specified by:
        getDataType in class Expression
        Returns:
        Value.ANY (meaning not known in advance)
      • getDependencies

        public int getDependencies()
        Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE
        Specified by:
        getDependencies in class Expression
      • reduce

        public Expression reduce​(int dependencies,
                                 Context context)
                          throws XPathException
        Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
        Specified by:
        reduce in class Expression
        Parameters:
        dependencies - The dependencies to be removed
        context - The context to be used for the partial evaluation
        Returns:
        a new expression that does not have any of the specified dependencies
        Throws:
        XPathException
      • display

        public void display​(int level)
        Diagnostic print of expression structure
        Specified by:
        display in class Expression