Package net.sf.saxon.pattern
Class VennPattern
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.PseudoExpression
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- net.sf.saxon.pattern.Pattern
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- net.sf.saxon.pattern.VennPattern
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- All Implemented Interfaces:
ExportAgent,Locatable,IdentityComparable,Traceable
- Direct Known Subclasses:
ExceptPattern,IntersectPattern,UnionPattern
public abstract class VennPattern extends Pattern
Abstract pattern formed as the union, intersection, or difference of two other patterns; concrete subclasses are used for the different operators
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Field Summary
Fields Modifier and Type Field Description protected Patternp1protected Patternp2-
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
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Constructor Summary
Constructors Constructor Description VennPattern(Pattern p1, Pattern p2)Constructor
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description intallocateSlots(SlotManager slotManager, int nextFree)Allocate slots to any variables used within the patternvoidbindCurrent(LocalBinding binding)Replace any calls on current() by a variable reference bound to the supplied bindingintcomputeHashCode()Hashcode supporting equals()booleanequals(java.lang.Object other)Determine whether this pattern is the same as another patternvoidexport(ExpressionPresenter presenter)Diagnostic print of expression structure.voidgatherComponentPatterns(java.util.Set<Pattern> set)Gather the component (non-Venn) patterns of this Venn patternintgetDependencies()Get the dependencies of the pattern.PatterngetLHS()Get the LHS of the unionprotected abstract java.lang.StringgetOperatorName()Get the relevant operator: "union", "intersect", or "except"PatterngetRHS()Get the RHS of the unionbooleanisMotionless()Test whether a pattern is motionless, that is, whether it can be evaluated against a node without repositioning the input stream.booleanmatchesCurrentGroup()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.java.lang.Stringreconstruct()Get the pattern text for diagnosticsPatternsimplify()Simplify the pattern: perform any context-independent optimisationsPatterntypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType)Type-check the pattern.-
Methods inherited from class net.sf.saxon.pattern.Pattern
convertToTypedPattern, copy, effectiveBooleanValue, getDefaultPriority, getFingerprint, getHostLanguage, getItemType, getOriginalText, getUType, handleDynamicError, isLiftable, isRecoverable, make, matches, matchesBeneathAnchor, optimize, patternContainsVariable, replaceCurrent, selectNodes, setOriginalText, setPriority, setRecoverable, toPattern, toShortString, toString
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Methods inherited from class net.sf.saxon.expr.PseudoExpression
computeCardinality, evaluateAsString, evaluateItem, getImplementationMethod, iterate, process
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getEvaluationMethod, getExpressionName, getExtraProperty, getIntegerBounds, getInterpretedExpression, 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, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplifyChildren, staticTypeCheck, suppressValidation, typeCheckChildren, typeError, unordered, verifyParentPointers
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface net.sf.saxon.trace.Traceable
gatherProperties
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Method Detail
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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:
operandsin classExpression- Returns:
- an iterator containing the sub-expressions of this expression
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simplify
public Pattern simplify() throws XPathException
Simplify the pattern: perform any context-independent optimisations- Overrides:
simplifyin classPattern- Returns:
- the simplified expression (or the original if unchanged, or if modified in-situ)
- Throws:
XPathException- if an error is discovered during expression rewriting
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typeCheck
public Pattern typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException
Type-check the pattern. This is only needed for patterns that contain variable references or function calls.- Overrides:
typeCheckin classPattern- Parameters:
visitor- the expression visitorcontextItemType- 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)
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bindCurrent
public void bindCurrent(LocalBinding binding)
Replace any calls on current() by a variable reference bound to the supplied binding- Overrides:
bindCurrentin classPattern
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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:
isMotionlessin classPattern- 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
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allocateSlots
public int allocateSlots(SlotManager slotManager, int nextFree)
Allocate slots to any variables used within the pattern- Overrides:
allocateSlotsin classPattern- Parameters:
slotManager- represents the stack frame on which slots are allocatednextFree- 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
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gatherComponentPatterns
public void gatherComponentPatterns(java.util.Set<Pattern> set)
Gather the component (non-Venn) patterns of this Venn pattern- Parameters:
set- the set into which the components will be added
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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.- Overrides:
getDependenciesin classPattern- Returns:
- the dependencies, as a bit-significant mask
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getLHS
public Pattern getLHS()
Get the LHS of the union- Returns:
- the first operand of the union
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getRHS
public Pattern getRHS()
Get the RHS of the union- Returns:
- the second operand of the union
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matchesCurrentGroup
public boolean matchesCurrentGroup()
Ask whether the pattern is anchored on a call on current-group()- Overrides:
matchesCurrentGroupin classPattern- 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
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equals
public boolean equals(java.lang.Object other)
Determine whether this pattern is the same as another pattern- Overrides:
equalsin classExpression- 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.
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computeHashCode
public int computeHashCode()
Hashcode supporting equals()- Overrides:
computeHashCodein classExpression- Returns:
- a computed hash code
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getOperatorName
protected abstract java.lang.String getOperatorName()
Get the relevant operator: "union", "intersect", or "except"- Returns:
- the operator, as a string
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reconstruct
public java.lang.String reconstruct()
Get the pattern text for diagnostics- Overrides:
reconstructin classPattern
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export
public void export(ExpressionPresenter presenter) throws XPathException
Description copied from class:ExpressionDiagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
exportin interfaceExportAgent- Specified by:
exportin classPattern- 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.
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