Package net.sf.saxon.expr.sort
Class DocumentSorter
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.UnaryExpression
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- net.sf.saxon.expr.sort.DocumentSorter
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- All Implemented Interfaces:
ExportAgent,Locatable,IdentityComparable,Traceable
public class DocumentSorter extends UnaryExpression
A DocumentSorter is an expression that sorts a sequence of nodes into document order.
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Field Summary
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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 DocumentSorter(Expression base)DocumentSorter(Expression base, boolean intraDocument)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description intcomputeSpecialProperties()Get the static properties of this expression (other than its type).Expressioncopy(RebindingMap rebindings)Copy an expression.booleaneffectiveBooleanValue(XPathContext context)Get the effective boolean value of the expression.voidexport(ExpressionPresenter out)Diagnostic print of expression structure.ItemOrderComparergetComparer()java.lang.StringgetExpressionName()Get a name identifying the kind of expression, in terms meaningful to a user.intgetImplementationMethod()An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().intgetNetCost()Return the net cost of evaluating this expression, excluding the cost of evaluating its operands.protected OperandRolegetOperandRole()Get the usage (in terms of streamability analysis) of the single operandjava.lang.StringgetStreamerName()Get the (partial) name of a class that supports streaming of this kind of expressionSequenceIteratoriterate(XPathContext context)Return an Iterator to iterate over the values of a sequence.Expressionoptimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)Perform optimisation of an expression and its subexpressions.Expressionsimplify()Simplify an expression.PatterntoPattern(Configuration config)Convert this expression to an equivalent XSLT patternExpressiontypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)Type-check the expression.Expressionunordered(boolean retainAllNodes, boolean forStreaming)Replace this expression by a simpler expression that delivers the results without regard to order.-
Methods inherited from class net.sf.saxon.expr.UnaryExpression
computeCardinality, computeHashCode, displayOperator, emitExtraAttributes, equals, getBaseExpression, getItemType, getOperand, operands, setBaseExpression, toShortString, toString
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Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getTracingTag, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isInstruction, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplifyChildren, staticTypeCheck, suppressValidation, typeCheckChildren, typeError, 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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Constructor Detail
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DocumentSorter
public DocumentSorter(Expression base)
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DocumentSorter
public DocumentSorter(Expression base, boolean intraDocument)
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Method Detail
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getOperandRole
protected OperandRole getOperandRole()
Description copied from class:UnaryExpressionGet the usage (in terms of streamability analysis) of the single operand- Specified by:
getOperandRolein classUnaryExpression- Returns:
- the operand usage
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getExpressionName
public java.lang.String getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.- Overrides:
getExpressionNamein classExpression- Returns:
- a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.
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getComparer
public ItemOrderComparer getComparer()
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simplify
public Expression simplify() throws XPathException
Description copied from class:ExpressionSimplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation simplifies its operands.- Overrides:
simplifyin classExpression- 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 Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
Description copied from class:UnaryExpressionType-check the expression. Default implementation for unary operators that accept any kind of operand- Overrides:
typeCheckin classUnaryExpression- Parameters:
visitor- an expression visitorcontextInfo- Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException- if an error is discovered during this phase (typically a type error)
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optimize
public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
Description copied from class:UnaryExpressionPerform optimisation of an expression and its subexpressions.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:
optimizein classUnaryExpression- Parameters:
visitor- an expression visitorcontextInfo- 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 toType.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)
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getNetCost
public int getNetCost()
Return the net cost of evaluating this expression, excluding the cost of evaluating its operands. We take the cost of evaluating a simple scalar comparison or arithmetic expression as 1 (one).- Overrides:
getNetCostin classExpression- Returns:
- the intrinsic cost of this operation, excluding the costs of evaluating the operands
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unordered
public Expression unordered(boolean retainAllNodes, boolean forStreaming) throws XPathException
Replace this expression by a simpler expression that delivers the results without regard to order.- Overrides:
unorderedin classExpression- Parameters:
retainAllNodes- set to true if the result must contain exactly the same nodes as the original; set to false if the result can eliminate (or introduce) duplicates.forStreaming- set to true if optimizing for streaming- Returns:
- an expression that delivers the same nodes in a more convenient order
- Throws:
XPathException- if the rewrite fails
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computeSpecialProperties
public int computeSpecialProperties()
Description copied from class:UnaryExpressionGet the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.- Overrides:
computeSpecialPropertiesin classUnaryExpression- Returns:
- the special properties, as a bit-significant integer
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copy
public Expression copy(RebindingMap rebindings)
Copy an expression. This makes a deep copy.- Specified by:
copyin classExpression- Parameters:
rebindings- variables that need to be re-bound- Returns:
- the copy of the original expression
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toPattern
public Pattern toPattern(Configuration config) throws XPathException
Convert this expression to an equivalent XSLT pattern- Overrides:
toPatternin classExpression- Parameters:
config- the Saxon configuration- Returns:
- the equivalent pattern
- Throws:
XPathException- if conversion is not possible
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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.- Specified by:
getImplementationMethodin classExpression- Returns:
- the implementation method, for example
Expression.ITERATE_METHODorExpression.EVALUATE_METHODorExpression.PROCESS_METHOD
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iterate
public SequenceIterator iterate(XPathContext context) throws XPathException
Description copied from class:ExpressionReturn an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.- Overrides:
iteratein classExpression- Parameters:
context- supplies the context for evaluation- Returns:
- a SequenceIterator that can be used to iterate over the result of the expression
- Throws:
XPathException- if any dynamic error occurs evaluating the expression
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effectiveBooleanValue
public boolean effectiveBooleanValue(XPathContext context) throws XPathException
Description copied from class:ExpressionGet the effective boolean value of the expression. This returns false if the value is the empty sequence, a zero-length string, a number equal to zero, or the boolean false. Otherwise it returns true.- Overrides:
effectiveBooleanValuein classExpression- Parameters:
context- The context in which the expression is to be evaluated- Returns:
- the effective boolean value
- Throws:
XPathException- if any dynamic error occurs evaluating the expression
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export
public void export(ExpressionPresenter out) throws XPathException
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.- Specified by:
exportin interfaceExportAgent- Overrides:
exportin classUnaryExpression- 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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getStreamerName
public java.lang.String getStreamerName()
Get the (partial) name of a class that supports streaming of this kind of expression- Overrides:
getStreamerNamein classExpression- Returns:
- the partial name of a class that can be instantiated to provide streaming support in Saxon-EE, or null if there is no such class
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