Package net.sf.saxon.pattern

Class LocationPathPattern

java.lang.Object
net.sf.saxon.pattern.Pattern
net.sf.saxon.pattern.LocationPathPattern
All Implemented Interfaces:
Serializable, SourceLocator, Container, PatternFinder
public final class LocationPathPattern extends Pattern
A LocationPathPattern represents a path, for example of the form A/B/C... The components are represented as a linked list, each component pointing to its predecessor
See Also:

  • Field Details

    • nodeTest

      public NodeTest nodeTest

    • filters

      protected Expression[] filters

    • equivalentExpr

      protected Expression equivalentExpr

    • firstElementPattern

      protected boolean firstElementPattern

    • lastElementPattern

      protected boolean lastElementPattern

    • specialFilter

      protected boolean specialFilter

  • Constructor Details

    • LocationPathPattern

      public LocationPathPattern()
      Create a LocationPathPattern

  • Method Details

    • setNodeTest

      public void setNodeTest(NodeTest test)
      Set the NodeTest
      Parameters:
      test - the NodeTest

    • setUpperPattern

      public void setUpperPattern(byte axis, Pattern upper)
      Set the superior pattern (matching a parent or ancestor node
      Parameters:
      axis - the axis (parent or ancestor) connecting to the upper pattern
      upper - the pattern that a parent or ancestor must match

    • addFilter

      public void addFilter(Expression filter)
      Add a filter to the pattern (while under construction)
      Parameters:
      filter - The predicate (a boolean expression or numeric expression) to be added

    • setLineNumber

      public void setLineNumber(int lineNumber)
      Description copied from class: Pattern
      Set the line number where the pattern occurred
      Overrides:
      setLineNumber in class Pattern
      Parameters:
      lineNumber - the line number of the pattern in the source module

    • setSystemId

      public void setSystemId(String systemId)
      Description copied from class: Pattern
      Set the system ID where the pattern occurred
      Overrides:
      setSystemId in class Pattern
      Parameters:
      systemId - the URI of the module containing the pattern

    • setExecutable

      public void setExecutable(Executable executable)
      Set the executable containing this pattern
      Overrides:
      setExecutable in class Pattern
      Parameters:
      executable - the executable

    • setVariableBindingExpression

      public void setVariableBindingExpression(Expression exp)
      Set an expression used to bind the variable that represents the value of the current() function
      Overrides:
      setVariableBindingExpression in class Pattern
      Parameters:
      exp - the expression that binds the variable

    • getFilters

      public Expression[] getFilters()
      Get the filters assocated with the last step in the pattern
      Returns:
      an array of expression holding the filter predicates in order

    • getUpperPattern

      public Pattern getUpperPattern()
      Get the pattern applying to the parent node, if there is one
      Returns:
      the parent pattern, for example if the pattern is a/b[1]/c then the parent pattern is a/b[1]

    • getUpwardsAxis

      public byte getUpwardsAxis()
      Get the upwards axis, that is, the axis by which the upper pattern is reached. Typically Axis.PARENT or Axis.ANCESTOR

    • selectsOutwards

      public boolean selectsOutwards()
      Test whether any predicate within the pattern contains a prohibited selection, that is, use of an axis such as child, descendant, following-sibling

    • simplify

      public Pattern simplify(ExpressionVisitor visitor) throws XPathException
      Simplify the pattern: perform any context-independent optimisations
      Overrides:
      simplify in class Pattern
      Parameters:
      visitor - an expression visitor
      Returns:
      the optimised Pattern
      Throws:
      XPathException - if a static error is discovered

    • analyze

      public Pattern analyze(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
      Type-check the pattern, performing any type-dependent optimizations.
      Overrides:
      analyze in class Pattern
      Parameters:
      visitor - an expression visitor
      contextItemType - the type of the context item at the point where the pattern appears
      Returns:
      the optimised Pattern
      Throws:
      XPathException - if a static error is discovered

    • 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

    • replaceSubExpression

      public boolean replaceSubExpression(Expression original, Expression replacement)
      Replace one subexpression by a replacement subexpression
      Overrides:
      replaceSubExpression in class Pattern
      Parameters:
      original - the original subexpression
      replacement - the replacement subexpression
      Returns:
      true if the original subexpression is 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 -
      nextFree - the next slot that is free to be allocated @return the next slot that is free to be allocated
      Returns:
      the next slot that is free to be allocated

    • promote

      public void promote(PromotionOffer offer, Expression parent) 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
      parent -
      Throws:
      XPathException - if any error is detected

    • matches

      public boolean matches(Item item, XPathContext context) throws XPathException
      Determine whether the pattern matches a given item.
      Specified by:
      matches in class Pattern
      Parameters:
      item - the item to be tested
      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 pattern matches, else false
      Throws:
      XPathException - if a dynamic error occurs during pattern matching

    • matchesBeneathAnchor

      public boolean matchesBeneathAnchor(NodeInfo node, NodeInfo anchor, XPathContext context) throws XPathException
      Determine whether this pattern matches a given Node within the subtree rooted at a given anchor node. This method is used when the pattern is used for streaming.
      Overrides:
      matchesBeneathAnchor in class Pattern
      Parameters:
      node - The NodeInfo representing the Element or other node to be tested against the Pattern
      anchor - The anchor node, which must match any AnchorPattern subpattern
      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 - if a dynamic error occurs during pattern matching

    • internalMatches

      protected boolean internalMatches(NodeInfo node, NodeInfo anchor, XPathContext context) throws XPathException
      Test whether the pattern matches, but without changing the current() node
      Overrides:
      internalMatches in class Pattern
      Parameters:
      node - The NodeInfo representing the Element or other node to be tested against the Pattern
      anchor - The anchor node, which must match any AnchorPattern subpattern
      context - The dynamic context. Only relevant if the pattern uses variables, or contains calls on functions such as document() or key(). @return true if the node matches the Pattern, false otherwise
      Returns:
      true if the pattern matches the supplied node
      Throws:
      XPathException - if a dynamic error occurs during pattern matching

    • getNodeKind

      public int getNodeKind()
      Determine the types of nodes to which this pattern applies. Used for optimisation. For patterns that match nodes of several types, return Node.NODE
      Overrides:
      getNodeKind in class Pattern
      Returns:
      the type of node matched by this pattern. e.g. Node.ELEMENT or Node.TEXT

    • getFingerprint

      public int getFingerprint()
      Determine the fingerprint of nodes to which this pattern applies. Used for optimisation.
      Overrides:
      getFingerprint in class Pattern
      Returns:
      the fingerprint of nodes matched by this pattern.

    • getItemType

      public ItemType getItemType()
      Get a NodeTest that all the nodes matching this pattern must satisfy
      Specified by:
      getItemType in class Pattern
      Returns:
      an ItemType, as specific as possible, which all the matching items satisfy

    • isPositional

      public boolean isPositional(TypeHierarchy th)
      Determine if the pattern uses positional filters
      Parameters:
      th - the type hierarchy cache
      Returns:
      true if there is a numeric filter in the pattern, or one that uses the position() or last() functions

    • resolveCurrent

      public void resolveCurrent(LetExpression let, PromotionOffer offer, boolean topLevel) throws XPathException
      If the pattern contains any calls on current(), this method is called to modify such calls to become variable references to a variable declared in a specially-allocated local variable
      Overrides:
      resolveCurrent in class Pattern
      Parameters:
      let - the expression that assigns the local variable. This returns a dummy result, and is executed just before evaluating the pattern, to get the value of the context item into the variable.
      offer - A PromotionOffer used to process the expressions and change the call on current() into a variable reference
      topLevel -
      Throws:
      XPathException

    • 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