Class Pattern

    • Constructor Detail

      • Pattern

        public Pattern()
    • Method Detail

      • make

        public static Pattern make​(java.lang.String pattern,
                                   StaticContext env,
                                   Executable exec)
                            throws XPathException
        Static factory 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
        exec - The executable containing this pattern
        Returns:
        The pattern object
        Throws:
        XPathException - if the pattern is invalid
      • getExecutable

        public Executable getExecutable()
        Get the executable containing this pattern
        Specified by:
        getExecutable in interface Container
        Returns:
        the executable
      • setExecutable

        public void setExecutable​(Executable executable)
        Set the executable containing this pattern
        Parameters:
        executable - the executable
      • getLocationProvider

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

        public int getContainerGranularity()
        Get the granularity of the container.
        Specified by:
        getContainerGranularity in interface Container
        Returns:
        0 for a temporary container created during parsing; 1 for a container that operates at the level of an XPath expression; 2 for a container at the level of a global function or template
      • setOriginalText

        public void setOriginalText​(java.lang.String text)
        Set the original text of the pattern for use in diagnostics
        Parameters:
        text - the original text of the pattern
      • setVariableBindingExpression

        public void setVariableBindingExpression​(Expression exp)
        Set an expression used to bind the variable that represents the value of the current() function
        Parameters:
        exp - the expression that binds the variable
      • simplify

        public Pattern simplify​(ExpressionVisitor visitor)
                         throws XPathException
        Simplify the pattern by applying any context-independent optimisations. Default implementation does nothing.
        Parameters:
        visitor - the 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.
        Parameters:
        visitor - the expression visitor
        contextItemType - the type of the context item at the point where the pattern is defined. Set to null if it is known that the context item is undefined.
        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.
        Returns:
        the dependencies, as a bit-significant mask
      • iterateSubExpressions

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

        public int allocateSlots​(StaticContext env,
                                 SlotManager slotManager,
                                 int nextFree)
        Allocate slots to any variables used within the 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
        Returns:
        the next slot that is free to be allocated
      • 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
        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 - true if this is an external call rather than an internal recursive call
        Throws:
        XPathException - if an error occurs
      • 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.

        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 - the expression acting as parent of this pattern
        Throws:
        XPathException - if any error is detected
      • setSystemId

        public void setSystemId​(java.lang.String systemId)
        Set the system ID where the pattern occurred
        Parameters:
        systemId - the URI of the module containing the pattern
      • setLineNumber

        public void setLineNumber​(int lineNumber)
        Set the line number where the pattern occurred
        Parameters:
        lineNumber - the line number of the pattern in the source module
      • matches

        public abstract boolean matches​(Item item,
                                        XPathContext context)
                                 throws XPathException
        Determine whether this Pattern matches the given item. This is the main external interface for matching patterns: it sets current() to the node being tested
        Parameters:
        item - 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 - 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.
        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
        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
        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 Type.NODE. For patterns that do not match nodes, return -1.
        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, or it if matches atomic values
      • getItemType

        public abstract ItemType getItemType()
        Get an ItemType that all the items matching this pattern must satisfy
        Returns:
        an ItemType, as specific as possible, which all the matching items 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.
        Returns:
        the default priority for the pattern
      • getSystemId

        public java.lang.String getSystemId()
        Get the system id of the entity in which the pattern occurred
        Specified by:
        getSystemId in interface javax.xml.transform.SourceLocator
      • getLineNumber

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

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

        public java.lang.String getPublicId()
        Get the public ID (always null)
        Specified by:
        getPublicId in interface javax.xml.transform.SourceLocator
      • toString

        public java.lang.String toString()
        Get the original pattern text
        Overrides:
        toString in class java.lang.Object
      • replaceSubExpression

        public boolean replaceSubExpression​(Expression original,
                                            Expression replacement)
        Replace a subexpression by a replacement subexpression
        Parameters:
        original - the expression to be replaced
        replacement - the new expression to be inserted in its place
        Returns:
        true if the replacement was carried out