Package net.sf.saxon.expr
Class AtomicSequenceConverter
- 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.AtomicSequenceConverter
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- All Implemented Interfaces:
ExportAgent,Locatable,IdentityComparable,Traceable
- Direct Known Subclasses:
UntypedSequenceConverter
public class AtomicSequenceConverter extends UnaryExpression
An AtomicSequenceConverter is an expression that performs a cast (or other supplied conversion) on each member of a supplied sequence
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Nested Class Summary
Nested Classes Modifier and Type Class Description static classAtomicSequenceConverter.AtomicSequenceMappingFunctionMapping function wrapped around a converterstatic classAtomicSequenceConverter.ToStringMappingFunctionMapping function that converts every item in a sequence to a string
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Field Summary
Fields Modifier and Type Field Description protected Converterconverterprotected PlainTyperequiredItemTypestatic AtomicSequenceConverter.ToStringMappingFunctionTO_STRING_MAPPER-
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 AtomicSequenceConverter(Expression sequence, PlainType requiredItemType)Constructor
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description ConverterallocateConverter(Configuration config, boolean allowNull)ConverterallocateConverter(Configuration config, boolean allowNull, ItemType sourceType)voidallocateConverterStatically(Configuration config, boolean allowNull)intcomputeCardinality()Determine the static cardinality of the expressionintcomputeHashCode()get HashCode for comparing two expressions.intcomputeSpecialProperties()Determine the special properties of this expressionExpressioncopy(RebindingMap rebindings)Copy an expression.protected java.lang.StringdisplayOperator(Configuration config)Give a string representation of the operator for use in diagnosticsbooleanequals(java.lang.Object other)Is this expression the same as another expression?AtomicValueevaluateItem(XPathContext context)Evaluate as an Item.voidexport(ExpressionPresenter destination)Diagnostic print of expression structure.ConvertergetConverter()Get the converter used to convert the items in the sequenceprotected ConvertergetConverterDynamically(XPathContext context)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().ItemTypegetItemType()Determine the data type of the items returned by the expression, if possibleprotected OperandRolegetOperandRole()Get the usage (in terms of streamability analysis) of the single operandPlainTypegetRequiredItemType()Get the required item type (the target type of the conversionRoleDiagnosticgetRoleDiagnostic()Get the RoleDiagnostic, used to give more precise error information if the conversion failsjava.lang.StringgetStreamerName()Get the (partial) name of a class that supports streaming of this kind of expressionSequenceIteratoriterate(XPathContext context)Iterate over the sequence of valuesExpressionoptimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)Perform optimisation of an expression and its subexpressions.voidsetConverter(Converter converter)voidsetRoleDiagnostic(RoleDiagnostic role)Set a RoleDiagnostic, used to give more precise error information if the conversion failsExpressionsimplify()Simplify an expressionExpressiontypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)Type-check the expression-
Methods inherited from class net.sf.saxon.expr.UnaryExpression
emitExtraAttributes, getBaseExpression, 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, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, 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, toPattern, 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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TO_STRING_MAPPER
public static AtomicSequenceConverter.ToStringMappingFunction TO_STRING_MAPPER
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requiredItemType
protected PlainType requiredItemType
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converter
protected Converter converter
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Constructor Detail
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AtomicSequenceConverter
public AtomicSequenceConverter(Expression sequence, PlainType requiredItemType)
Constructor- Parameters:
sequence- this must be a sequence of atomic values. This is not checked; a ClassCastException will occur if the precondition is not satisfied.requiredItemType- the item type to which all items in the sequence should be converted,
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Method Detail
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allocateConverterStatically
public void allocateConverterStatically(Configuration config, boolean allowNull)
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allocateConverter
public Converter allocateConverter(Configuration config, boolean allowNull)
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getConverterDynamically
protected Converter getConverterDynamically(XPathContext context)
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allocateConverter
public Converter allocateConverter(Configuration config, boolean allowNull, ItemType sourceType)
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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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getRequiredItemType
public PlainType getRequiredItemType()
Get the required item type (the target type of the conversion- Returns:
- the required item type
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getConverter
public Converter getConverter()
Get the converter used to convert the items in the sequence- Returns:
- the converter. Note that a converter is always allocated during the typeCheck() phase, even if the source type is not known.
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setConverter
public void setConverter(Converter converter)
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setRoleDiagnostic
public void setRoleDiagnostic(RoleDiagnostic role)
Set a RoleDiagnostic, used to give more precise error information if the conversion fails- Parameters:
role- the RoleDiagnostic, which gives more precise error information
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getRoleDiagnostic
public RoleDiagnostic getRoleDiagnostic()
Get the RoleDiagnostic, used to give more precise error information if the conversion fails- Returns:
- the RoleDiagnostic, or null if none has been set
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simplify
public Expression simplify() throws XPathException
Simplify an expression- 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
Type-check the expression- 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
Perform optimisation of an expression and its subexpressions.- 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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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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computeSpecialProperties
public int computeSpecialProperties()
Determine the special properties of this expression- Overrides:
computeSpecialPropertiesin classUnaryExpression- Returns:
StaticProperty.NO_NODES_NEWLY_CREATED.
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getStreamerName
public java.lang.String getStreamerName()
Description copied from class:ExpressionGet 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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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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iterate
public SequenceIterator iterate(XPathContext context) throws XPathException
Iterate over the sequence of values- 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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evaluateItem
public AtomicValue evaluateItem(XPathContext context) throws XPathException
Evaluate as an Item. This should only be called if the AtomicSequenceConverter has cardinality zero-or-one- Overrides:
evaluateItemin classExpression- Parameters:
context- The context in which the expression is to be evaluated- Returns:
- the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
- Throws:
XPathException- if any dynamic error occurs evaluating the expression
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getItemType
public ItemType getItemType()
Determine the data type of the items returned by the expression, if possible- Overrides:
getItemTypein classUnaryExpression- Returns:
- a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)
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computeCardinality
public int computeCardinality()
Determine the static cardinality of the expression- Overrides:
computeCardinalityin classUnaryExpression- Returns:
- the computed cardinality, as one of the values
StaticProperty.ALLOWS_ZERO_OR_ONE,StaticProperty.EXACTLY_ONE,StaticProperty.ALLOWS_ONE_OR_MORE,StaticProperty.ALLOWS_ZERO_OR_MORE. May also returnStaticProperty.ALLOWS_ZEROif the result is known to be an empty sequence, orStaticProperty.ALLOWS_MANYif if is known to return a sequence of length two or more.
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equals
public boolean equals(java.lang.Object other)
Is this expression the same as another expression?- Overrides:
equalsin classUnaryExpression- Parameters:
other- 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.
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computeHashCode
public int computeHashCode()
get HashCode for comparing two expressions. Note that this hashcode gives the same result for (A op B) and for (B op A), whether or not the operator is commutative.- Overrides:
computeHashCodein classUnaryExpression- Returns:
- a computed hash code
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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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displayOperator
protected java.lang.String displayOperator(Configuration config)
Description copied from class:UnaryExpressionGive a string representation of the operator for use in diagnostics- Overrides:
displayOperatorin classUnaryExpression- Parameters:
config- the Saxon configuration- Returns:
- the operator, as a string
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export
public void export(ExpressionPresenter destination) 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:
destination- 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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