java.lang.Object
- net.sf.saxon.expr.Expression
- - net.sf.saxon.expr.PseudoExpression
  - - net.sf.saxon.pattern.Pattern
    - - net.sf.saxon.pattern.NodeSetPattern

All Implemented Interfaces:

ExportAgent, Locatable, IdentityComparable, Traceable
```
public class NodeSetPattern
extends Pattern
```
A NodeSetPattern is a pattern based on an expression that is evaluated to return a set of nodes; a node matches the pattern if it is a member of this node-set.
In XSLT 2.0 there are two forms of NodeSetPattern allowed, represented by calls on the id() and key() functions. In XSLT 3.0, additional forms are allowed, for example a variable reference, and a call to the doc() function. This class provides the general capability to use any expression at the head of a pattern. This is used also to support streaming, where streaming XPath expressions are mapped to patterns.

Field Summary
- Fields inherited from class net.sf.saxon.expr.Expression
  EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

Constructor Summary

Constructors
Constructor Description

NodeSetPattern(Expression exp)
Create a node-set pattern.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`allocateSlots(SlotManager slotManager, int nextFree)`	Allocate slots to any variables used within the pattern
`protected int`	`computeHashCode()`	Hashcode supporting equals()
`Pattern`	`copy(RebindingMap rebindings)`	Copy a pattern.
`boolean`	`equals(java.lang.Object other)`	Determine whether this pattern is the same as another pattern
`void`	`export(ExpressionPresenter presenter)`	Diagnostic print of expression structure.
`int`	`getDependencies()`	Get the dependencies of the pattern.
`ItemType`	`getItemType()`	Get a NodeTest that all the nodes matching this pattern must satisfy
`Expression`	`getSelectionExpression()`	Get the underlying expression
`UType`	`getUType()`	Get a UType indicating which kinds of items this Pattern can match.
`boolean`	`isMotionless()`	Test whether a pattern is motionless, that is, whether it can be evaluated against a node without repositioning the input stream.
`boolean`	`matches(Item item, XPathContext context)`	Determine whether this Pattern matches the given Node
`java.lang.Iterable<Operand>`	`operands()`	Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.
`Pattern`	`optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)`	Perform optimisation of an expression and its subexpressions.
`SequenceIterator`	`selectNodes(TreeInfo doc, XPathContext context)`	Select nodes in a document using this PatternFinder.
`void`	`setItemType(ItemType type)`	Set the item type, that is, the type of nodes/items which the pattern will match
`Pattern`	`typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType)`	Type-check the pattern.

Methods inherited from class net.sf.saxon.pattern.Pattern
bindCurrent, convertToTypedPattern, effectiveBooleanValue, getDefaultPriority, getElaborator, getFingerprint, getHostLanguage, getOriginalText, handleDynamicError, isLiftable, isRecoverable, make, matchesBeneathAnchor, matchesCurrentGroup, matchesItem, patternContainsVariable, reconstruct, replaceCurrent, setOriginalText, setPriority, setRecoverable, simplify, toPattern, toShortString, toString

Methods inherited from class net.sf.saxon.expr.PseudoExpression
computeCardinality, evaluateAsString, evaluateItem, getImplementationMethod, iterate, process

Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, dispatchTailCall, dynamicError, explain, getCardinality, getConfiguration, getCost, getEvaluationMethod, getExpressionName, getExtraProperty, getIntegerBounds, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getStreamerName, getTracingTag, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isInstruction, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, makeElaborator, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplifyChildren, staticTypeCheck, supportsLazyEvaluation, suppressValidation, typeCheckChildren, typeError, unordered, verifyParentPointers, withLocation

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sf.saxon.trace.Traceable
gatherProperties

- Constructor Detail
  - NodeSetPattern
```
public NodeSetPattern(Expression exp)
```
    Create a node-set pattern.
    
    Parameters:
    
    exp - an expression that can be evaluated to return a node-set; a node matches the pattern if it is present in this node-set. The expression must not depend on the focus, though it can depend on other aspects of the dynamic context such as local or global variables.
- Method Detail
  - operands
```
public java.lang.Iterable<Operand> operands()
```
    Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()
    If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.
    
    Overrides:
    
    operands in class Expression
    
    Returns:
    
    an iterator containing the sub-expressions of this expression
  - getSelectionExpression
```
public Expression getSelectionExpression()
```
    Get the underlying expression
    
    Returns:
    
    the expression that returns all the selected nodes
  - typeCheck
```
public Pattern typeCheck(ExpressionVisitor visitor,
                         ContextItemStaticInfo contextItemType)
                  throws XPathException
```
    Type-check the pattern. Default implementation does nothing. This is only needed for patterns that contain variable references or function calls.
    
    Overrides:
    
    typeCheck 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 - if an error is discovered during this phase (typically a type error)
  - optimize
```
public Pattern optimize(ExpressionVisitor visitor,
                        ContextItemStaticInfo contextInfo)
                 throws XPathException
```
    Description copied from class: Pattern
    
    Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.
    This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
    
    Overrides:
    
    optimize in class Pattern
    
    Parameters:
    
    visitor - an expression visitor
    
    contextInfo - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
    
    Returns:
    
    the original expression, rewritten if appropriate to optimize execution
    
    Throws:
    
    XPathException - if an error is discovered during this phase (typically a type error)
  - setItemType
```
public void setItemType(ItemType type)
```
    Set the item type, that is, the type of nodes/items which the pattern will match
    
    Parameters:
    
    type - the item type that the pattern will match
  - 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.
    
    Overrides:
    
    getDependencies in class Pattern
    
    Returns:
    
    the dependencies, as a bit-significant mask
  - isMotionless
```
public boolean isMotionless()
```
    Test whether a pattern is motionless, that is, whether it can be evaluated against a node without repositioning the input stream. This is a necessary condition for patterns used as the match pattern of a streamed template rule.
    
    Overrides:
    
    isMotionless in class Pattern
    
    Returns:
    
    true if the pattern is motionless, that is, if it can be evaluated against a streamed node without changing the position in the streamed input file
  - allocateSlots
```
public int allocateSlots(SlotManager slotManager,
                         int nextFree)
```
    Allocate slots to any variables used within the pattern
    
    Overrides:
    
    allocateSlots in class Pattern
    
    Parameters:
    
    slotManager - the slot manager representing the stack frame for local variables
    
    nextFree - the next slot that is free to be allocated @return the next slot that is free to be allocated
    
    Returns:
    
    the next slot that is free to be allocated
  - selectNodes
```
public SequenceIterator selectNodes(TreeInfo doc,
                                    XPathContext context)
                             throws XPathException
```
    Select nodes in a document using this PatternFinder.
    
    Overrides:
    
    selectNodes in class Pattern
    
    Parameters:
    
    doc - the document node at the root of a tree
    
    context - the dynamic evaluation context
    
    Returns:
    
    an iterator over the selected nodes in the document.
    
    Throws:
    
    XPathException
  - matches
```
public boolean matches(Item item,
                       XPathContext context)
                throws XPathException
```
    Determine whether this Pattern matches the given Node
    
    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.
    
    Returns:
    
    true if the node matches the Pattern, false otherwise
    
    Throws:
    
    XPathException - if an error occurs while matching the pattern
  - getUType
```
public UType getUType()
```
    Get a UType indicating which kinds of items this Pattern can match.
    
    Specified by:
    
    getUType in class Pattern
    
    Returns:
    
    a UType indicating all the primitive types of item that the pattern can match.
  - getItemType
```
public ItemType getItemType()
```
    Get a NodeTest that all the nodes matching this pattern must satisfy
    
    Specified by:
    
    getItemType in class Pattern
    
    Returns:
    
    an ItemType, as specific as possible, which all the matching items satisfy
  - equals
```
public boolean equals(java.lang.Object other)
```
    Determine whether this pattern is the same as another pattern
    
    Overrides:
    
    equals in class Expression
    
    Parameters:
    
    other - the other object
    
    Returns:
    
    true if the other operand is an expression and if it can be determined that the two expressions are equivalent, in the sense that they will always return the same result.
  - computeHashCode
```
protected int computeHashCode()
```
    Hashcode supporting equals()
    
    Overrides:
    
    computeHashCode in class Expression
    
    Returns:
    
    a computed hash code
  - copy
```
public Pattern copy(RebindingMap rebindings)
```
    Copy a pattern. This makes a deep copy.
    
    Specified by:
    
    copy in class Pattern
    
    Parameters:
    
    rebindings - variable bindings to be changed if encountered
    
    Returns:
    
    the copy of the original pattern
  - export
```
public void export(ExpressionPresenter presenter)
            throws XPathException
```
    Description copied from class: Expression
    
    Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
    
    Specified by:
    
    export in interface ExportAgent
    
    Specified by:
    
    export in class Pattern
    
    Parameters:
    
    presenter - the expression presenter used to display the structure
    
    Throws:
    
    XPathException - if the export fails, for example if an expression is found that won't work in the target environment.

Class NodeSetPattern

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

Constructor Summary

Method Summary

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

Methods inherited from class net.sf.saxon.expr.PseudoExpression

Methods inherited from class net.sf.saxon.expr.Expression

Methods inherited from class java.lang.Object

Methods inherited from interface net.sf.saxon.trace.Traceable

Constructor Detail

NodeSetPattern

Method Detail

operands

getSelectionExpression

typeCheck

optimize

setItemType

getDependencies

isMotionless

allocateSlots

selectNodes

matches

getUType

getItemType

equals

computeHashCode

copy

export