net.sf.saxon.pattern
Class AnchorPattern

java.lang.Object
  net.sf.saxon.pattern.Pattern
      net.sf.saxon.pattern.AnchorPattern

All Implemented Interfaces:

Serializable, SourceLocator, Container, PatternFinder

public class AnchorPattern
extends Pattern

This is a special pattern that matches the "anchor node"; it is not used for XSLT patterns, but for the selectors that arise when evaluating XPath expressions in streaming mode; the anchor node is the context node for the streamed XPath evaluation.

See Also:

Serialized Form

Constructor Summary

AnchorPattern()

Method Summary

Pattern	analyze(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Type-check the pattern.
ItemType	getItemType() Get a NodeTest that all the nodes matching this pattern must satisfy
protected boolean	internalMatches(NodeInfo node, NodeInfo anchor, XPathContext context) Determine whether this Pattern matches the given Node.
boolean	matches(Item item, XPathContext context) Determine whether this Pattern matches the given Node.
boolean	matchesBeneathAnchor(NodeInfo node, NodeInfo anchor, XPathContext context) Determine whether this pattern matches a given Node within the subtree rooted at a given anchor node.
String	toString() Get the original pattern text

Methods inherited from class net.sf.saxon.pattern.Pattern

allocateSlots, getColumnNumber, getContainerGranularity, getDefaultPriority, getDependencies, getExecutable, getFingerprint, getHostLanguage, getLineNumber, getLocationProvider, getNodeKind, getPublicId, getSystemId, iterateSubExpressions, make, promote, replaceSubExpression, resolveCurrent, selectNodes, setExecutable, setLineNumber, setOriginalText, setSystemId, simplify

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AnchorPattern

public AnchorPattern()

Method Detail

analyze

public Pattern analyze(ExpressionVisitor visitor,
                       ExpressionVisitor.ContextItemType contextItemType)
                throws XPathException

Type-check the pattern.

Overrides:

analyze in class 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

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

matches

public boolean matches(Item item,
                       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

Specified by:

matches in class Pattern

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

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().

Overrides:

internalMatches in class Pattern

Parameters:

node - The NodeInfo representing the Element or other node to be tested against the Pattern

anchor -

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

getItemType

public ItemType getItemType()

Get a NodeTest that all the nodes matching this pattern must satisfy

Specified by:

getItemType in class Pattern

Returns:

a NodeTest, as specific as possible, which all the matching nodes satisfy

toString

public String toString()

Description copied from class: Pattern

Get the original pattern text

Overrides:

toString in class Pattern