Package net.sf.saxon.expr.sort
Class SortKeyDefinition
- 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.expr.sort.SortKeyDefinition
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- All Implemented Interfaces:
ExportAgent,Locatable,IdentityComparable,Traceable
public class SortKeyDefinition extends PseudoExpression
A SortKeyDefinition defines one component of a sort key.Note that most attributes defining the sort key can be attribute value templates, and can therefore vary from one invocation to another. We hold them as expressions.
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Field Summary
Fields Modifier and Type Field Description protected booleanbackwardsCompatibleprotected java.lang.StringbaseURIprotected OperandcaseOrderprotected StringCollatorcollationprotected OperandcollationNameprotected OperanddataTypeExpressionprotected booleanemptyLeastprotected Operandlanguageprotected Operandorderprotected booleansetContextForSortKeyprotected OperandsortKeyprotected Operandstable-
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 SortKeyDefinition()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description intcomputeHashCode()Get a hashcode to reflect the equals() methodSortKeyDefinitioncopy(RebindingMap rm)Copy this SortKeyDefinitionbooleanequals(java.lang.Object other)Compare two SortKeyDefinition values for equality.voidexport(ExpressionPresenter out)Diagnostic print of expression structure.SortKeyDefinitionfix(XPathContext context)java.lang.StringgetBaseURI()Get the static base URI of the expression.ExpressiongetCaseOrder()Get the expression that defines the case order of the sort keys.StringCollatorgetCollation()Get the collation to be usedExpressiongetCollationNameExpression()Get the selected collation name (specifically, an expression which when evaluated returns the collation URI).ExpressiongetDataTypeExpression()Get the expression that defines the data type of the sort keysbooleangetEmptyLeast()Ask whether empty sequence comes before other values or after themAtomicComparergetFinalComparator()Get the comparator which is used to compare two values according to this sort key.intgetImplementationMethod()An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().ExpressiongetLanguage()Get the expression that defines the language of the sort keysExpressiongetOrder()Get the expression that defines the order as ascending or descendingExpressiongetSortKey()Get the expression used as the sort keyOperandgetSortKeyOperand()Get the sort key operandExpressiongetStable()Ask whether this sort key definition is stablebooleanisBackwardsCompatible()Ask whether this sort key is evaluated in XSLT 1.0 backwards compatibility modebooleanisFixed()Ask whether the sort key definition is fixed, that is, whether all the information needed to create a Comparator is known staticallybooleanisLiftable(boolean forStreaming)Ask whether the expression can be lifted out of a loop, assuming it has no dependencies on the controlling variable/focus of the loopbooleanisSetContextForSortKey()Ask whether the sortkey is to be evaluated with the item-being-sorted as the context itemAtomicComparermakeComparator(XPathContext context)Allocate an AtomicComparer to perform the comparisons described by this sort key component.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.voidsetBackwardsCompatible(boolean compatible)Set whether this sort key is evaluated in XSLT 1.0 backwards compatibility modevoidsetBaseURI(java.lang.String baseURI)Set the base URI of the expression.voidsetCaseOrder(Expression exp)Set the case order.voidsetCollation(StringCollator collation)Set the collation to be usedvoidsetCollationNameExpression(Expression collationNameExpr)Set the collation name (specifically, an expression which when evaluated returns the collation URI).voidsetDataTypeExpression(Expression exp)Set the data type.voidsetEmptyLeast(boolean emptyLeast)Set whether empty sequence comes before other values or after themvoidsetFinalComparator(AtomicComparer comp)Set the comparator which is used to compare two values according to this sort key.voidsetLanguage(Expression exp)Set the language.voidsetOrder(Expression exp)Set the order.voidsetSortKey(Expression exp, boolean setContext)Set the expression used as the sort keyvoidsetStable(Expression stableExpr)Set whether this sort key definition is stableSortKeyDefinitiontypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType)Type-check this sort key definition (all properties other than the sort key select expression, when it has a different dynamic context)-
Methods inherited from class net.sf.saxon.expr.PseudoExpression
computeCardinality, effectiveBooleanValue, evaluateAsString, evaluateItem, getItemType, 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, getDependencies, 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, optimize, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, 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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Field Detail
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sortKey
protected Operand sortKey
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order
protected Operand order
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dataTypeExpression
protected Operand dataTypeExpression
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caseOrder
protected Operand caseOrder
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language
protected Operand language
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collationName
protected Operand collationName
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stable
protected Operand stable
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collation
protected StringCollator collation
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baseURI
protected java.lang.String baseURI
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emptyLeast
protected boolean emptyLeast
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backwardsCompatible
protected boolean backwardsCompatible
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setContextForSortKey
protected boolean setContextForSortKey
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Method Detail
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isLiftable
public boolean isLiftable(boolean forStreaming)
Ask whether the expression can be lifted out of a loop, assuming it has no dependencies on the controlling variable/focus of the loop- Overrides:
isLiftablein classExpression- Parameters:
forStreaming- true if we are optimizing for streamed evaluation- Returns:
- true if the expression can be loop lifted
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setSortKey
public void setSortKey(Expression exp, boolean setContext)
Set the expression used as the sort key- Parameters:
exp- the sort key select expressionsetContext- set to true if the sort key is to be evaluated with the item-being-sorted as the context item (as in XSLT); false if the context item is not to be set (as in XQuery)
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getSortKey
public Expression getSortKey()
Get the expression used as the sort key- Returns:
- the sort key select expression
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getSortKeyOperand
public Operand getSortKeyOperand()
Get the sort key operand- Returns:
- the operand that computes the sort key
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isSetContextForSortKey
public boolean isSetContextForSortKey()
Ask whether the sortkey is to be evaluated with the item-being-sorted as the context item- Returns:
- true if the context needs to be set for evaluating the sort key
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setOrder
public void setOrder(Expression exp)
Set the order. This is supplied as an expression which must evaluate to "ascending" or "descending". If the order is fixed, supply e.g. new StringValue("ascending"). Default is "ascending".- Parameters:
exp- the expression that determines the order (always a literal in XQuery, but can be defined by an AVT in XSLT)
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getOrder
public Expression getOrder()
Get the expression that defines the order as ascending or descending- Returns:
- the expression that determines the order (always a literal in XQuery, but can be defined by an AVT in XSLT)
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setDataTypeExpression
public void setDataTypeExpression(Expression exp)
Set the data type. This is supplied as an expression which must evaluate to "text", "number", or a QName. If the data type is fixed, the valus should be supplied using setDataType() and not via this method.- Parameters:
exp- the expression that defines the data type, as used in XSLT 1.0
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getDataTypeExpression
public Expression getDataTypeExpression()
Get the expression that defines the data type of the sort keys- Returns:
- the expression that defines the data type, as used in XSLT 1.0
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setCaseOrder
public void setCaseOrder(Expression exp)
Set the case order. This is supplied as an expression which must evaluate to "upper-first" or "lower-first" or "#default". If the order is fixed, supply e.g. new StringValue("lower-first"). Default is "#default".- Parameters:
exp- the expression that defines the case order
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getCaseOrder
public Expression getCaseOrder()
Get the expression that defines the case order of the sort keys.- Returns:
- the expression that defines the case order, whose run-time value will be "upper-first", "lower-first", or "#default".
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setLanguage
public void setLanguage(Expression exp)
Set the language. This is supplied as an expression which evaluates to the language name. If the order is fixed, supply e.g. new StringValue("de").- Parameters:
exp- the expression that determines the language
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getLanguage
public Expression getLanguage()
Get the expression that defines the language of the sort keys- Returns:
- exp the expression that determines the language
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setCollationNameExpression
public void setCollationNameExpression(Expression collationNameExpr)
Set the collation name (specifically, an expression which when evaluated returns the collation URI).- Parameters:
collationNameExpr- the expression that determines the collation name
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getCollationNameExpression
public Expression getCollationNameExpression()
Get the selected collation name (specifically, an expression which when evaluated returns the collation URI).- Returns:
- the expression that determines the collation name
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setCollation
public void setCollation(StringCollator collation)
Set the collation to be used- Parameters:
collation- A StringCollator, which encapsulates both the collation URI and the collating function
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getCollation
public StringCollator getCollation()
Get the collation to be used- Returns:
- A StringCollator, which encapsulates both the collation URI and the collating function
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setBaseURI
public void setBaseURI(java.lang.String baseURI)
Set the base URI of the expression. This is needed to handle the case where a collation URI evaluated at run-time turns out to be a relative URI.- Parameters:
baseURI- the static base URI of the expression
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getBaseURI
public java.lang.String getBaseURI()
Get the static base URI of the expression. This is needed to handle the case where a collation URI evaluated at run-time turns out to be a relative URI.- Returns:
- the static base URI of the expression
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setStable
public void setStable(Expression stableExpr)
Set whether this sort key definition is stable- Parameters:
stableExpr- the expression that determines whether the sort key definition is stable (it evaluates to the string "yes" or "no".
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getStable
public Expression getStable()
Ask whether this sort key definition is stable- Returns:
- the expression that determines whether the sort key definition is stable (it evaluates to the string "yes" or "no".
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setBackwardsCompatible
public void setBackwardsCompatible(boolean compatible)
Set whether this sort key is evaluated in XSLT 1.0 backwards compatibility mode- Parameters:
compatible- true if backwards compatibility mode is selected
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isBackwardsCompatible
public boolean isBackwardsCompatible()
Ask whether this sort key is evaluated in XSLT 1.0 backwards compatibility mode- Returns:
- true if backwards compatibility mode was selected
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setEmptyLeast
public void setEmptyLeast(boolean emptyLeast)
Set whether empty sequence comes before other values or after them- Parameters:
emptyLeast- true if () is considered lower than any other value
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getEmptyLeast
public boolean getEmptyLeast()
Ask whether empty sequence comes before other values or after them- Returns:
- true if () is considered lower than any other value
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isFixed
public boolean isFixed()
Ask whether the sort key definition is fixed, that is, whether all the information needed to create a Comparator is known statically- Returns:
- true if all information needed to create a Comparator is known statically
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copy
public SortKeyDefinition copy(RebindingMap rm)
Copy this SortKeyDefinition- Specified by:
copyin classExpression- Parameters:
rm- a mutable list of (old binding, new binding) pairs that is used to update the bindings held in any local variable references that are copied.- Returns:
- a copy of this SortKeyDefinition
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typeCheck
public SortKeyDefinition typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException
Type-check this sort key definition (all properties other than the sort key select expression, when it has a different dynamic context)- Overrides:
typeCheckin classExpression- Parameters:
visitor- the expression visitorcontextItemType- the type of the context item- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException- if any failure occurs
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operands
public java.lang.Iterable<Operand> operands()
Description copied from class:ExpressionGet 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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getImplementationMethod
public int getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.- Overrides:
getImplementationMethodin classPseudoExpression- Returns:
- the implementation method, for example
Expression.ITERATE_METHODorExpression.EVALUATE_METHODorExpression.PROCESS_METHOD
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makeComparator
public AtomicComparer makeComparator(XPathContext context) throws XPathException
Allocate an AtomicComparer to perform the comparisons described by this sort key component. The AtomicComparer takes into account not only the collation, but also parameters such as order=descending and handling of empty sequence and NaN (the result of the compare() method of the comparator is +1 if the second item is to sort after the first item). The AtomicComparer is allocated at compile time if possible (during typeCheck), otherwise at run-time.- Parameters:
context- the dynamic evaluation context- Returns:
- an AtomicComparer suitable for making the sort comparisons
- Throws:
XPathException- for example if the collation URI is invalid or unknown
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setFinalComparator
public void setFinalComparator(AtomicComparer comp)
Set the comparator which is used to compare two values according to this sort key. The comparator makes the final decision whether one value sorts before or after another: this takes into account the data type, the collation, whether empty comes first or last, whether the sort order is ascending or descending.This method is called at compile time if all these factors are known at compile time. It must not be called at run-time, except to reconstitute a finalComparator that has been lost by virtue of serialization .
- Parameters:
comp- the Atomic Comparer to be used
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getFinalComparator
public AtomicComparer getFinalComparator()
Get the comparator which is used to compare two values according to this sort key. This method may be called either at compile time or at run-time. If no comparator has been allocated, it returns null. It is then necessary to allocate a comparator using themakeComparator(net.sf.saxon.expr.XPathContext)method.- Returns:
- the Atomic Comparer to be used
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fix
public SortKeyDefinition fix(XPathContext context) throws XPathException
- Throws:
XPathException
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equals
public boolean equals(java.lang.Object other)
Compare two SortKeyDefinition values for equality. This compares the sortKeys and attribute values.- Overrides:
equalsin classExpression- Parameters:
other- SortKeyDefinition- Returns:
- boolean
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computeHashCode
public int computeHashCode()
Get a hashcode to reflect the equals() method- Overrides:
computeHashCodein classExpression- Returns:
- a hashcode based sortkey attribute values.
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export
public void export(ExpressionPresenter out) 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 classExpression- Parameters:
out- 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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