Package net.sf.saxon.pattern
Class Pattern
- java.lang.Object
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- net.sf.saxon.pattern.Pattern
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,PatternFinder
- Direct Known Subclasses:
IDPattern
,KeyPattern
,LocationPathPattern
,NodeTestPattern
,UnionPattern
public abstract class Pattern extends java.lang.Object implements PatternFinder, java.io.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:
- Serialized Form
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Constructor Summary
Constructors Constructor Description Pattern()
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description int
allocateSlots(StaticContext env, SlotManager slotManager, int nextFree)
Allocate slots to any variables used within the patternPattern
analyze(ExpressionVisitor visitor, ItemType contextItemType)
Type-check the pattern.int
getColumnNumber()
Get the column number (always -1)double
getDefaultPriority()
Determine the default priority to use if this pattern appears as a match pattern for a template with no explicit priority attribute.int
getDependencies()
Get the dependencies of the pattern.Executable
getExecutable()
Get the executable containing this patternint
getFingerprint()
Determine the name fingerprint of nodes to which this pattern applies.int
getHostLanguage()
Get the host language (XSLT, XQuery, XPath) used to implement the code in this containerint
getLineNumber()
Get the line number on which the pattern was definedLocationProvider
getLocationProvider()
Get the LocationProvider allowing location identifiers to be resolved.int
getNodeKind()
Determine the types of nodes to which this pattern applies.abstract NodeTest
getNodeTest()
Get a NodeTest that all the nodes matching this pattern must satisfyjava.lang.String
getPublicId()
Get the public ID (always null)java.lang.String
getSystemId()
Get the system id of the entity in which the pattern occurredprotected boolean
internalMatches(NodeInfo node, XPathContext context)
Determine whether this Pattern matches the given Node.java.util.Iterator
iterateSubExpressions()
Iterate over the subexpressions within this patternstatic Pattern
make(java.lang.String pattern, StaticContext env, Executable exec)
Static method to make a Pattern by parsing a String.Expression
makeSearchExpression()
Make an expression whose effect is to select all the nodes that match this pattern in a given document.abstract boolean
matches(NodeInfo node, XPathContext context)
Determine whether this Pattern matches the given Node.void
promote(PromotionOffer offer)
Offer promotion for subexpressions within this pattern.boolean
replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpressionSequenceIterator
selectNodes(DocumentInfo doc, XPathContext context)
Select nodes in a document using this PatternFinder.void
setExecutable(Executable executable)
Set the executable containing this patternvoid
setLineNumber(int lineNumber)
Set the line number where the pattern occurredvoid
setOriginalText(java.lang.String text)
Set the original text of the pattern for use in diagnosticsvoid
setSystemId(java.lang.String systemId)
Set the system ID where the pattern occurredPattern
simplify(ExpressionVisitor visitor)
Simplify the pattern by applying any context-independent optimisations.java.lang.String
toString()
Get the original pattern text
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Method Detail
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make
public static Pattern make(java.lang.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 Stringenv
- An object defining the compile-time context for the expressionexec
- The executable containing this pattern- Returns:
- The pattern object
- Throws:
XPathException
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getExecutable
public Executable getExecutable()
Get the executable containing this pattern- Specified by:
getExecutable
in interfaceContainer
- Returns:
- the executable
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setExecutable
public void setExecutable(Executable executable)
Set the executable containing this pattern- Parameters:
executable
- the executable
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getLocationProvider
public LocationProvider getLocationProvider()
Get the LocationProvider allowing location identifiers to be resolved.- Specified by:
getLocationProvider
in interfaceContainer
- Returns:
- the location provider
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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
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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
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analyze
public Pattern analyze(ExpressionVisitor visitor, 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.- Parameters:
visitor
- the expression visitorcontextItemType
- the type of the context item, if known, at the point where the pattern is defined- Returns:
- the optimised Pattern
- Throws:
XPathException
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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
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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
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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 stylesheetslotManager
- the slot manager representing the stack frame for local variablesnextFree
- the next slot that is free to be allocated @return the next slot that is free to be allocated
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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
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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
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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
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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 Patterncontext
- 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
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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 Patterncontext
- 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
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selectNodes
public SequenceIterator selectNodes(DocumentInfo doc, XPathContext context) throws XPathException
Select nodes in a document using this PatternFinder.- Specified by:
selectNodes
in interfacePatternFinder
- Parameters:
doc
- the document node at the root of a treecontext
- the dynamic evaluation context- Returns:
- an iterator over the selected nodes in the document.
- Throws:
XPathException
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makeSearchExpression
public Expression makeSearchExpression()
Make an expression whose effect is to select all the nodes that match this pattern in a given document. This expression takes the root of the tree (always a document node) as the context node; it takes into account all the constraints expressed by the pattern including the parent and ancestor nodes and the filters
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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
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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
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getNodeTest
public abstract NodeTest getNodeTest()
Get a NodeTest that all the nodes matching this pattern must satisfy- Returns:
- a NodeTest, as specific as possible, which all the matching nodes satisfy
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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
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getSystemId
public java.lang.String getSystemId()
Get the system id of the entity in which the pattern occurred- Specified by:
getSystemId
in interfacejavax.xml.transform.SourceLocator
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getLineNumber
public int getLineNumber()
Get the line number on which the pattern was defined- Specified by:
getLineNumber
in interfacejavax.xml.transform.SourceLocator
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getColumnNumber
public int getColumnNumber()
Get the column number (always -1)- Specified by:
getColumnNumber
in interfacejavax.xml.transform.SourceLocator
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getPublicId
public java.lang.String getPublicId()
Get the public ID (always null)- Specified by:
getPublicId
in interfacejavax.xml.transform.SourceLocator
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toString
public java.lang.String toString()
Get the original pattern text- Overrides:
toString
in classjava.lang.Object
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getHostLanguage
public int getHostLanguage()
Get the host language (XSLT, XQuery, XPath) used to implement the code in this container- Specified by:
getHostLanguage
in interfaceContainer
- Returns:
- typically
Configuration.XSLT
orConfiguration.XQUERY
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replaceSubExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
Description copied from interface:Container
Replace one subexpression by a replacement subexpression- Specified by:
replaceSubExpression
in interfaceContainer
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression was found
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