Class KeyPattern

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

    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​(StructuredQName keyName,
                          Expression key)
        Constructor
        Parameters:
        keyName - the name of the key
        key - the value of the key: either a StringValue or a VariableReference
    • Method Detail

      • analyze

        public Pattern analyze​(ExpressionVisitor visitor,
                               ItemType contextItemType)
                        throws XPathException
        Type-check the pattern. This is needed for patterns that contain variable references or function calls.
        Overrides:
        analyze in class Pattern
        Parameters:
        visitor - the expression visitor
        contextItemType - the type of the context item, if known, at the point where the pattern is defined
        Returns:
        the optimised Pattern
        Throws:
        XPathException
      • 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
        Returns:
        the dependencies, as a bit-significant mask
      • iterateSubExpressions

        public java.util.Iterator iterateSubExpressions()
        Iterate over the subexpressions within this pattern
        Overrides:
        iterateSubExpressions in class Pattern
        Returns:
        an iterator over the subexpressions. Default implementation returns an empty sequence
      • 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
      • replaceSubExpression

        public boolean replaceSubExpression​(Expression original,
                                            Expression replacement)
        Description copied from interface: Container
        Replace one subexpression by a replacement subexpression
        Specified by:
        replaceSubExpression in interface Container
        Overrides:
        replaceSubExpression in class Pattern
        Parameters:
        original - the original subexpression
        replacement - the replacement subexpression
        Returns:
        true if the original subexpression was found
      • allocateSlots

        public int allocateSlots​(StaticContext env,
                                 SlotManager slotManager,
                                 int nextFree)
        Allocate slots to any variables used within the pattern
        Overrides:
        allocateSlots in class Pattern
        Parameters:
        env - the static context in the XSLT stylesheet
        slotManager - the slot manager representing the stack frame for local variables
        nextFree - the next slot that is free to be allocated @return the next slot that is free to be allocated
      • 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
        Returns:
        a NodeTest, as specific as possible, which all the matching nodes satisfy
      • equals

        public boolean equals​(java.lang.Object other)
        Determine whether this pattern is the same as another pattern
        Overrides:
        equals in class java.lang.Object
        Parameters:
        other - the other object
      • hashCode

        public int hashCode()
        Hashcode supporting equals()
        Overrides:
        hashCode in class java.lang.Object