Class KeyPattern

java.lang.Object
net.sf.saxon.pattern.Pattern
net.sf.saxon.pattern.KeyPattern
All Implemented Interfaces:
Serializable, SourceLocator, Container, PatternFinder

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

    • 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 Details

    • 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 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(Object other)
      Determine whether this pattern is the same as another pattern
      Overrides:
      equals in class Object
      Parameters:
      other - the other object
    • hashCode

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