Class Pattern

java.lang.Object
net.sf.saxon.pattern.Pattern
All Implemented Interfaces:
Serializable, SourceLocator, Container
Direct Known Subclasses:
IDPattern, KeyPattern, LocationPathPattern, NodeTestPattern, UnionPattern

public abstract class Pattern extends Object implements Serializable, Container
A Pattern represents the result of parsing an XSLT pattern string.
Patterns are created by calling the static method Pattern.make(string).
The pattern is used to test a particular node by calling match().
See Also:
  • Constructor Details

    • Pattern

      public Pattern()
  • Method Details

    • make

      public static Pattern make(String pattern, StaticContext env, Executable exec) throws XPathException
      Static method to make a Pattern by parsing a String.
      Parameters:
      pattern - The pattern text as a String
      env - An object defining the compile-time context for the expression
      Returns:
      The pattern object
      Throws:
      XPathException
    • getExecutable

      public Executable getExecutable()
      Description copied from interface: Container
      Get the Executable (representing a complete stylesheet or query) of which this Container forms part
      Specified by:
      getExecutable in interface Container
    • setExecutable

      public void setExecutable(Executable executable)
    • getLocationProvider

      public LocationProvider getLocationProvider()
      Get the LocationProvider allowing location identifiers to be resolved.
      Specified by:
      getLocationProvider in interface Container
    • setOriginalText

      public void setOriginalText(String text)
      Set the original text of the pattern for use in diagnostics
    • simplify

      public Pattern simplify(StaticContext env) throws XPathException
      Simplify the pattern by applying any context-independent optimisations. Default implementation does nothing.
      Returns:
      the optimised Pattern
      Throws:
      XPathException
    • analyze

      public Pattern analyze(StaticContext env, ItemType contextItemType) throws XPathException
      Type-check the pattern. Default implementation does nothing. This is only needed for patterns that contain variable references or function calls.
      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.
    • iterateSubExpressions

      public Iterator iterateSubExpressions()
      Iterate over the subexpressions within this 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.

      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
    • setSystemId

      public void setSystemId(String systemId)
      Set the system ID where the pattern occurred
    • setLineNumber

      public void setLineNumber(int lineNumber)
      Set the line number where the pattern occurred
    • matches

      public abstract boolean matches(NodeInfo node, XPathContext context) throws XPathException
      Determine whether this Pattern matches the given Node. This is the main external interface for matching patterns: it sets current() to the node being tested
      Parameters:
      node - 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
    • internalMatches

      protected boolean internalMatches(NodeInfo node, XPathContext context) throws XPathException
      Determine whether this Pattern matches the given Node. This is an internal interface used for matching sub-patterns; it does not alter the value of current(). The default implementation is identical to matches().
      Parameters:
      node - 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
    • 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 Type.NODE
      Returns:
      the type of node matched by this pattern. e.g. Type.ELEMENT or Type.TEXT
    • getFingerprint

      public int getFingerprint()
      Determine the name fingerprint of nodes to which this pattern applies. Used for optimisation.
      Returns:
      A fingerprint that the nodes must match, or -1 if it can match multiple fingerprints
    • getNodeTest

      public abstract NodeTest getNodeTest()
      Get a NodeTest that all the nodes matching this pattern must satisfy
    • getDefaultPriority

      public double getDefaultPriority()
      Determine the default priority to use if this pattern appears as a match pattern for a template with no explicit priority attribute.
    • getSystemId

      public String getSystemId()
      Get the system id of the entity in which the pattern occurred
      Specified by:
      getSystemId in interface SourceLocator
    • getLineNumber

      public int getLineNumber()
      Get the line number on which the pattern was defined
      Specified by:
      getLineNumber in interface SourceLocator
    • getColumnNumber

      public int getColumnNumber()
      Get the column number (always -1)
      Specified by:
      getColumnNumber in interface SourceLocator
    • getPublicId

      public String getPublicId()
      Get the public ID (always null)
      Specified by:
      getPublicId in interface SourceLocator
    • toString

      public String toString()
      Get the original pattern text
      Overrides:
      toString in class Object
    • getHostLanguage

      public int getHostLanguage()
      Get the host language (XSLT, XQuery, XPath) used to implement the code in this container
      Specified by:
      getHostLanguage in interface Container
      Returns:
      typically Configuration.XSLT or Configuration.XQUERY
    • 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
      Parameters:
      original - the original subexpression
      replacement - the replacement subexpression
      Returns:
      true if the original subexpression was found