Class Navigator


  • public final class Navigator
    extends java.lang.Object
    The Navigator class provides helper classes for navigating a tree, irrespective of its implementation
    Author:
    Michael H. Kay
    • Method Detail

      • getAttributeValue

        public static java.lang.String getAttributeValue​(NodeInfo element,
                                                         java.lang.String uri,
                                                         java.lang.String localName)
        Get the string value of an attribute of a given element, given the URI and local part of the attribute name.
        Parameters:
        uri - The namespace URI. The null URI is represented as an empty string.
        localName - The local part of the name.
        Returns:
        the attribute value, or null if the attribute is not present
      • getBaseURI

        public static java.lang.String getBaseURI​(NodeInfo node)
        Helper method to get the base URI of an element or processing instruction node
      • getPath

        public static java.lang.String getPath​(NodeInfo node)
        Get an absolute XPath expression that identifies a given node within its document
        Parameters:
        node - the node whose path is required. If null is supplied, an empty string is returned - this fact is used in making a recursive call for a parentless node.
        Returns:
        a path expression that can be used to retrieve the node
      • getNumberSimple

        public static int getNumberSimple​(NodeInfo node,
                                          XPathContext context)
                                   throws XPathException
        Get simple node number. This is defined as one plus the number of previous siblings of the same node type and name. It is not accessible directly in XSL.
        Parameters:
        node - The node whose number is required
        context - Used for remembering previous result, for performance
        Returns:
        the node number, as defined above
        Throws:
        XPathException - if any error occurs
      • getNumberSingle

        public static int getNumberSingle​(NodeInfo node,
                                          Pattern count,
                                          Pattern from,
                                          XPathContext context)
                                   throws XPathException
        Get node number (level="single"). If the current node matches the supplied pattern, the returned number is one plus the number of previous siblings that match the pattern. Otherwise, return the element number of the nearest ancestor that matches the supplied pattern.
        Parameters:
        node - the current node, the one whose node number is required
        count - Pattern that identifies which nodes should be counted. Default (null) is the element name if the current node is an element, or "node()" otherwise.
        from - Pattern that specifies where counting starts from. Default (null) is the root node. (This parameter does not seem useful but is included for the sake of XSLT conformance.)
        context - the dynamic context of the transformation, used if the patterns reference context values (e.g. variables)
        Returns:
        the node number established as follows: go to the nearest ancestor-or-self that matches the 'count' pattern and that is a descendant of the nearest ancestor that matches the 'from' pattern. Return one plus the nunber of preceding siblings of that ancestor that match the 'count' pattern. If there is no such ancestor, return 0.
        Throws:
        XPathException - when any error occurs in processing
      • getNumberAny

        public static int getNumberAny​(Expression inst,
                                       NodeInfo node,
                                       Pattern count,
                                       Pattern from,
                                       XPathContext context,
                                       boolean hasVariablesInPatterns)
                                throws XPathException
        Get node number (level="any"). Return one plus the number of previous nodes in the document that match the supplied pattern
        Parameters:
        inst - Identifies the xsl:number expression; this is relevant when the function is memoised to support repeated use of the same instruction to number multiple nodes
        node - The node being numbered
        count - Pattern that identifies which nodes should be counted. Default (null) is the element name if the current node is an element, or "node()" otherwise.
        from - Pattern that specifies where counting starts from. Default (null) is the root node. Only nodes after the first (most recent) node that matches the 'from' pattern are counted.
        context - The dynamic context for the transformation
        hasVariablesInPatterns - if the count or from patterns contain variables, then it's not safe to get the answer by adding one to the number of the most recent node that matches
        Returns:
        one plus the number of nodes that precede the current node, that match the count pattern, and that follow the first node that matches the from pattern if specified.
        Throws:
        XPathException
      • getNumberMulti

        public static java.util.List getNumberMulti​(NodeInfo node,
                                                    Pattern count,
                                                    Pattern from,
                                                    XPathContext context)
                                             throws XPathException
        Get node number (level="multiple"). Return a vector giving the hierarchic position of this node. See the XSLT spec for details.
        Parameters:
        node - The node to be numbered
        count - Pattern that identifies which nodes (ancestors and their previous siblings) should be counted. Default (null) is the element name if the current node is an element, or "node()" otherwise.
        from - Pattern that specifies where counting starts from. Default (null) is the root node. Only nodes below the first (most recent) node that matches the 'from' pattern are counted.
        context - The dynamic context for the transformation
        Returns:
        a vector containing for each ancestor-or-self that matches the count pattern and that is below the nearest node that matches the from pattern, an Integer which is one greater than the number of previous siblings that match the count pattern.
        Throws:
        XPathException
      • copy

        public static void copy​(NodeInfo node,
                                Receiver out,
                                NamePool namePool,
                                int whichNamespaces,
                                boolean copyAnnotations,
                                int locationId)
                         throws XPathException
        Generic (model-independent) implementation of deep copy algorithm for nodes. This is available for use by any node implementations that choose to use it.
        Parameters:
        node - The node to be copied
        out - The receiver to which events will be sent
        namePool - Namepool holding the name codes (used only to resolve namespace codes)
        whichNamespaces - Indicates which namespace nodes for an element should be copied
        copyAnnotations - Indicates whether type annotations should be copied
        Throws:
        XPathException - on any failure reported by the Receiver
      • compareOrder

        public static int compareOrder​(SiblingCountingNode first,
                                       SiblingCountingNode second)
        Generic (model-independent) method to determine the relative position of two node in document order. The nodes must be in the same tree.
        Parameters:
        first - The first node
        second - The second node, whose position is to be compared with the first node
        Returns:
        -1 if this node precedes the other node, +1 if it follows the other node, or 0 if they are the same node. (In this case, isSameNode() will always return true, and the two nodes will produce the same result for generateId())
      • appendSequentialKey

        public static void appendSequentialKey​(SiblingCountingNode node,
                                               FastStringBuffer sb,
                                               boolean addDocNr)
        Get a character string that uniquely identifies this node and that collates nodes into document order
      • alphaKey

        public static java.lang.String alphaKey​(int value)
        Construct an alphabetic key from an positive integer; the key collates in the same sequence as the integer
        Parameters:
        value - The positive integer key value (negative values are treated as zero).
      • isWhite

        public static final boolean isWhite​(java.lang.CharSequence content)
        Deprecated.
        Determine if a string is all-whitespace
        Parameters:
        content - the string to be tested
        Returns:
        true if the supplied string contains no non-whitespace characters
      • isAncestorOrSelf

        public static boolean isAncestorOrSelf​(NodeInfo a,
                                               NodeInfo d)
        Test if one node is an ancestor-or-self of another
        Parameters:
        a - the putative ancestor-or-self node
        d - the putative descendant node
        Returns:
        true if a is an ancestor-or-self of d
      • filteredSingleton

        public static AxisIterator filteredSingleton​(NodeInfo node,
                                                     NodeTest nodeTest)
        Create an iterator over a singleton node, if it exists and matches a nodetest; otherwise return an empty iterator
        Parameters:
        node - the singleton node, or null if the node does not exist
        nodeTest - the test to be applied
        Returns:
        an iterator over the node if it exists and matches the test.