Constructor Detail

• NormalizeSpace

  public NormalizeSpace​()

Method Detail

• getIntrinsicDependencies

  public int getIntrinsicDependencies​()

  Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

  Overrides:

  getIntrinsicDependencies in class Expression

  Returns:

  a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

• typeCheck

  public Expression typeCheck​(ExpressionVisitor visitor,
                              ItemType contextItemType)
                       throws XPathException

  Description copied from class: FunctionCall
  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:

  typeCheck in class FunctionCall

  Parameters:

  visitor - an expression visitor

  contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

  Returns:

  the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

  Throws:

  XPathException - if an error is discovered during this phase (typically a type error)

• preEvaluate

  public Expression preEvaluate​(ExpressionVisitor visitor)
                         throws XPathException

  Pre-evaluate a function at compile time. Functions that do not allow pre-evaluation, or that need access to context information, can override this method.

  Overrides:

  preEvaluate in class FunctionCall

  Parameters:

  visitor - an expression visitor

  Returns:

  the result of the early evaluation, or the original expression, or potentially a simplified expression

  Throws:

  XPathException

• evaluateItem

  public Item evaluateItem​(XPathContext c)
                    throws XPathException

  Evaluate in a general context

  Specified by:

  evaluateItem in interface EvaluableItem

  Overrides:

  evaluateItem in class Expression

  Parameters:

  c - The context in which the expression is to be evaluated

  Returns:

  the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

  Throws:

  XPathException - if any dynamic error occurs evaluating the expression

• effectiveBooleanValue

  public boolean effectiveBooleanValue​(XPathContext c)
                                throws XPathException

  Get the effective boolean value of the expression. This returns false if the value is the empty sequence, a zero-length string, a number equal to zero, or the boolean false. Otherwise it returns true.

  This method is implemented for normalize-space() because it is quite often used in a boolean context to test whether a value exists and is non-white, and because testing for the presence of non-white characters is a lot more efficient than constructing the normalized string, especially because of early-exit.

  Overrides:

  effectiveBooleanValue in class Expression

  Parameters:

  c - The context in which the expression is to be evaluated

  Returns:

  the effective boolean value

  Throws:

  XPathException - if any dynamic error occurs evaluating the expression