Class KeyPattern

  • All Implemented Interfaces:
    java.io.Serializable, javax.xml.transform.SourceLocator, Container

    public final class KeyPattern
    extends Pattern
    A KeyPattern is a pattern of the form key(keyname, keyvalue)
    See Also:
    Serialized Form
    • Constructor Detail

      • KeyPattern

        public KeyPattern​(int namecode,
                          Expression key)
        Constructor
        Parameters:
        namecode - the name of the key
        key - the value of the key: either a StringValue or a VariableReference
    • Method Detail

      • getDependencies

        public int getDependencies()
        Get the dependencies of the pattern. The only possible dependency for a pattern is on local variables. This is analyzed in those patterns where local variables may appear.
        Overrides:
        getDependencies in class Pattern
      • iterateSubExpressions

        public java.util.Iterator iterateSubExpressions()
        Iterate over the subexpressions within this pattern
        Overrides:
        iterateSubExpressions in class Pattern
      • promote

        public void promote​(PromotionOffer offer)
                     throws XPathException
        Offer promotion for subexpressions within this pattern. The offer will be accepted if the subexpression is not dependent on the factors (e.g. the context item) identified in the PromotionOffer. By default the offer is not accepted - this is appropriate in the case of simple expressions such as constant values and variable references where promotion would give no performance advantage. This method is always called at compile time.

        Unlike the corresponding method on Expression, this method does not return anything: it can make internal changes to the pattern, but cannot return a different pattern. Only certain kinds of promotion are applicable within a pattern: specifically, promotions affecting local variable references within the pattern.

        Overrides:
        promote in class Pattern
        Parameters:
        offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
        Throws:
        XPathException - if any error is detected
      • matches

        public boolean matches​(NodeInfo e,
                               XPathContext context)
                        throws XPathException
        Determine whether this Pattern matches the given Node.
        Specified by:
        matches in class Pattern
        Parameters:
        e - The NodeInfo representing the Element or other node to be tested against the Pattern
        context - The dynamic context. Only relevant if the pattern uses variables, or contains calls on functions such as document() or key().
        Returns:
        true if the node matches the Pattern, false otherwise
        Throws:
        XPathException
      • getNodeTest

        public NodeTest getNodeTest()
        Get a NodeTest that all the nodes matching this pattern must satisfy
        Specified by:
        getNodeTest in class Pattern