net.sf.saxon.pattern

Class Pattern

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().
Method Summary
Patternanalyze(StaticContext env, ItemType contextItemType)
Type-check the pattern.
intgetColumnNumber()
Get the column number (always -1)
doublegetDefaultPriority()
Determine the default priority to use if this pattern appears as a match pattern for a template with no explicit priority attribute.
intgetDependencies()
Get the dependencies of the pattern.
ExecutablegetExecutable()
intgetFingerprint()
Determine the name fingerprint of nodes to which this pattern applies.
intgetHostLanguage()
Get the host language (XSLT, XQuery, XPath) used to implement the code in this container
intgetLineNumber()
Get the line number on which the pattern was defined
LocationProvidergetLocationProvider()
Get the LocationProvider allowing location identifiers to be resolved.
intgetNodeKind()
Determine the types of nodes to which this pattern applies.
abstract NodeTestgetNodeTest()
Get a NodeTest that all the nodes matching this pattern must satisfy
StringgetPublicId()
Get the public ID (always null)
StringgetSystemId()
Get the system id of the entity in which the pattern occurred
protected booleaninternalMatches(NodeInfo node, XPathContext context)
Determine whether this Pattern matches the given Node.
IteratoriterateSubExpressions()
Iterate over the subexpressions within this pattern
static Patternmake(String pattern, StaticContext env, Executable exec)
Static method to make a Pattern by parsing a String.
abstract booleanmatches(NodeInfo node, XPathContext context)
Determine whether this Pattern matches the given Node.
voidpromote(PromotionOffer offer)
Offer promotion for subexpressions within this pattern.
voidsetExecutable(Executable executable)
voidsetLineNumber(int lineNumber)
Set the line number where the pattern occurred
voidsetOriginalText(String text)
Set the original text of the pattern for use in diagnostics
voidsetSystemId(String systemId)
Set the system ID where the pattern occurred
Patternsimplify(StaticContext env)
Simplify the pattern by applying any context-independent optimisations.
StringtoString()
Get the original pattern text

Method Detail

analyze

public Pattern analyze(StaticContext env, ItemType contextItemType)
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

getColumnNumber

public int getColumnNumber()
Get the column number (always -1)

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.

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.

getExecutable

public Executable getExecutable()

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

getHostLanguage

public int getHostLanguage()
Get the host language (XSLT, XQuery, XPath) used to implement the code in this container

Returns: typically XSLT or XQUERY

getLineNumber

public int getLineNumber()
Get the line number on which the pattern was defined

getLocationProvider

public LocationProvider getLocationProvider()
Get the LocationProvider allowing location identifiers to be resolved.

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

getNodeTest

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

getPublicId

public String getPublicId()
Get the public ID (always null)

getSystemId

public String getSystemId()
Get the system id of the entity in which the pattern occurred

internalMatches

protected boolean internalMatches(NodeInfo node, XPathContext context)
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

iterateSubExpressions

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

make

public static Pattern make(String pattern, StaticContext env, Executable exec)
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

matches

public abstract boolean matches(NodeInfo node, XPathContext context)
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

promote

public void promote(PromotionOffer offer)
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: net.sf.saxon.trans.XPathException if any error is detected

setExecutable

public void setExecutable(Executable executable)

setLineNumber

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

setOriginalText

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

setSystemId

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

simplify

public Pattern simplify(StaticContext env)
Simplify the pattern by applying any context-independent optimisations. Default implementation does nothing.

Returns: the optimised Pattern

toString

public String toString()
Get the original pattern text