net.sf.saxon.pattern

Class BasePatternWithPredicate

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.PseudoExpression

net.sf.saxon.pattern.Pattern

net.sf.saxon.pattern.BasePatternWithPredicate

All Implemented Interfaces:

ExportAgent, Locatable, IdentityComparable, PatternWithPredicate

public class BasePatternWithPredicate
extends Pattern
implements PatternWithPredicate

Class for handling patterns with simple non-positional boolean predicates

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 and Description
BasePatternWithPredicate(Pattern basePattern, Expression predicate)

Method Summary

Modifier and Type	Method and Description
int	allocateSlots(SlotManager slotManager, int nextFree) Allocate slots to any variables used within the pattern
void	bindCurrent(LocalBinding binding) Replace any calls on current() by a variable reference bound to the supplied binding
int	computeHashCode() Compute a hash code, which will then be cached for later use
Pattern	convertToTypedPattern(java.lang.String val) Convert the pattern to a typed pattern, in which an element name is treated as schema-element(N)
Pattern	copy(RebindingMap rebindings) Copy a pattern.
boolean	equals(java.lang.Object obj) The equals() test for expressions returns true if it can be determined that two expressions (given their static context) will return the same result in all circumstances.
void	export(ExpressionPresenter presenter) Diagnostic print of expression structure.
Pattern	getBasePattern()
int	getDependencies() Get the dependencies of the pattern.
int	getFingerprint() Determine the name fingerprint of nodes to which this pattern applies.
ItemType	getItemType() Get an ItemType that all the items matching this pattern must satisfy
Expression	getPredicate()
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.
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.
boolean	matchesCurrentGroup() Ask whether the pattern is anchored on a call on current-group()
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.
java.lang.String	toShortString() Produce a short string identifying the expression for use in error messages
java.lang.String	toString() Display the pattern for diagnostics
Pattern	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Type-check the pattern.

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

effectiveBooleanValue, getDefaultPriority, getHostLanguage, handleDynamicError, isLiftable, isRecoverable, make, patternContainsVariable, replaceCurrent, selectNodes, setOriginalText, setPriority, setRecoverable, simplify

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, dynamicError, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getEvaluationMethod, getExpressionName, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getStreamerName, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isInstruction, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, typeCheckChildren, typeError, unordered, verifyParentPointers

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

BasePatternWithPredicate

public BasePatternWithPredicate(Pattern basePattern,
                                Expression predicate)

Method Detail

getPredicate

public Expression getPredicate()

Specified by:

getPredicate in interface PatternWithPredicate

getBasePattern

public Pattern getBasePattern()

bindCurrent

public void bindCurrent(LocalBinding binding)

Replace any calls on current() by a variable reference bound to the supplied binding

Overrides:

bindCurrent in class Pattern

matchesCurrentGroup

public boolean matchesCurrentGroup()

Ask whether the pattern is anchored on a call on current-group()

Overrides:

matchesCurrentGroup in class Pattern

Returns:

true if calls on matchesBeneathAnchor should test with all nodes in the current group as anchor nodes. If false, only the first node in a group is treated as the anchor node

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

allocateSlots

public int allocateSlots(SlotManager slotManager,
                         int nextFree)

Allocate slots to any variables used within the pattern

Overrides:

allocateSlots in class Pattern

Parameters:

slotManager - holds details of the allocated slots

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

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. 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 - if an error occurs while matching the pattern (the caller will usually treat this the same as a false result)

matchesBeneathAnchor

public boolean matchesBeneathAnchor(NodeInfo node,
                                    NodeInfo anchor,
                                    XPathContext context)
                             throws XPathException

Description copied from class: Pattern

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 - if an error occurs while matching the pattern (the caller will usually treat this the same as a false result)

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.

getFingerprint

public int getFingerprint()

Determine the name fingerprint of nodes to which this pattern applies. Used for optimisation.

Overrides:

getFingerprint in class Pattern

Returns:

A fingerprint that the nodes must match, or -1 if it can match multiple fingerprints, or it if matches atomic values

getItemType

public ItemType getItemType()

Get an ItemType that all the items matching this pattern must satisfy

Specified by:

getItemType in class Pattern

Returns:

an ItemType, as specific as possible, which all the matching items satisfy

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

typeCheck

public Pattern typeCheck(ExpressionVisitor visitor,
                         ContextItemStaticInfo contextItemType)
                  throws XPathException

Type-check the pattern.

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

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)

convertToTypedPattern

public Pattern convertToTypedPattern(java.lang.String val)
                              throws XPathException

Convert the pattern to a typed pattern, in which an element name is treated as schema-element(N)

Overrides:

convertToTypedPattern in class Pattern

Parameters:

val - either "strict" or "lax" depending on the value of xsl:mode/@typed

Returns:

either the original pattern unchanged, or a new pattern as the result of the conversion

Throws:

XPathException - if the pattern cannot be converted

isMotionless

public boolean isMotionless()

Description copied from class: Pattern

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

toString

public java.lang.String toString()

Display the pattern for diagnostics

Overrides:

toString in class Pattern

Returns:

a representation of the expression as a string

toShortString

public java.lang.String toShortString()

Description copied from class: Expression

Produce a short string identifying the expression for use in error messages

Overrides:

toShortString in class Pattern

Returns:

a short string, sufficient to identify the expression

copy

public Pattern copy(RebindingMap rebindings)

Copy a pattern. This makes a deep copy.

Specified by:

copy in class Pattern

Parameters:

rebindings - variables that need to be re-bound

Returns:

the copy of the original pattern

equals

public boolean equals(java.lang.Object obj)

Description copied from class: Expression

The equals() test for expressions returns true if it can be determined that two expressions (given their static context) will return the same result in all circumstances. The value false is returned if this is not the case or if it cannot be determined to be the case.

During the various phases of compilation, expression objects are mutable. Changing an expression may change its hashCode, and may change the result of equals() comparisons. Expressions should therefore not be held in data structures such as maps and sets that depend on equality comparison unless they are no longer subject to such mutation.

Overrides:

equals in class Expression

Parameters:

obj - the other operand; the result is false if this is not an Expression

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

public int computeHashCode()

Description copied from class: Expression

Compute a hash code, which will then be cached for later use

Overrides:

computeHashCode in class Expression

Returns:

a computed hash code

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.