Package com.saxonica.ee.stream
Class StreamInstr
java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.instruct.Instruction
net.sf.saxon.expr.instruct.SourceDocument
com.saxonica.ee.stream.StreamInstr
- All Implemented Interfaces:
Pusher
,ExportAgent
,Locatable
,IdentityComparable
,Traceable
Implementation of the xsl:source-document (streamable="yes") instruction
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Nested Class Summary
Nested Classes -
Field Summary
Fields inherited from class net.sf.saxon.expr.instruct.SourceDocument
accumulators, bodyOp, hrefOp, parseOptions
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 -
Method Summary
Modifier and TypeMethodDescriptioncheckStreamability
(List<String> reasons, boolean enabled, boolean strict) int
Compute the dependencies of an expression, as the union of the dependencies of its subexpressions.protected int
Get the static properties of this expression (other than its type).copy
(RebindingMap rebindings) Copy an expression.Make an elaborator for this expressioniterate
(XPathContext context) Return an Iterator to iterate over the values of a sequence.boolean
Determine whether this instruction creates new nodes.optimize
(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Perform optimisation of an expression and its subexpressions.void
void
process
(Outputter output, XPathContext context) Process the instruction, without returning any tail callsvoid
push
(Outputter output, XPathContext context) Evaluate the instruction in push modevoid
Set the whitespace stripping rule to be used.Methods inherited from class net.sf.saxon.expr.instruct.SourceDocument
allowExtractingCommonSubexpressions, export, getBody, getExpressionName, getHref, operands, setBody, setHref, setUsedAccumulators, typeCheck
Methods inherited from class net.sf.saxon.expr.instruct.Instruction
alwaysCreatesNewNodes, assembleParams, assembleTunnelParams, computeCardinality, dynamicError, evaluateAsString, evaluateItem, getImplementationMethod, getInstructionNameCode, getItemType, getNetCost, getSourceLocator, isInstruction, isXSLT, someOperandCreatesNewNodes
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeHashCode, computeStaticProperties, dispatchTailCall, dynamicError, effectiveBooleanValue, equals, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, getStreamerName, getTracingTag, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, makeElaborator, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, supportsLazyEvaluation, suppressValidation, toPattern, toShortString, toString, typeCheckChildren, typeError, unordered, verifyParentPointers, withLocation
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface net.sf.saxon.trace.Traceable
gatherProperties
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Constructor Details
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StreamInstr
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Method Details
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setSpaceStrippingRule
Description copied from class:SourceDocument
Set the whitespace stripping rule to be used. (This method is used when reloading the instruction from a SEF file)- Overrides:
setSpaceStrippingRule
in classSourceDocument
- Parameters:
rule
- the whitespace stripping rule
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optimize
public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) 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 classSourceDocument
- Parameters:
visitor
- an expression visitorcontextItemType
- 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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prepareForStreaming
- Throws:
XPathException
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prepareForStreaming
- Overrides:
prepareForStreaming
in classExpression
- Throws:
XPathException
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checkStreamability
public Expression checkStreamability(List<String> reasons, boolean enabled, boolean strict) throws XPathException - Throws:
XPathException
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mayCreateNewNodes
public boolean mayCreateNewNodes()Determine whether this instruction creates new nodes. This implementation returns a default value of false- Overrides:
mayCreateNewNodes
in classSourceDocument
- Returns:
- true if the instruction creates new nodes (or if it can't be proved that it doesn't)
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computeDependencies
public int computeDependencies()Compute the dependencies of an expression, as the union of the dependencies of its subexpressions. (This is overridden for path expressions and filter expressions, where the dependencies of a subexpression are not all propogated). This method should be called only once, to compute the dependencies; after that, getDependencies should be used.- Overrides:
computeDependencies
in classSourceDocument
- Returns:
- the depencies, as a bit-mask
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computeSpecialProperties
protected int computeSpecialProperties()Get 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:
computeSpecialProperties
in classSourceDocument
- Returns:
- a set of flags indicating static properties of this expression
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getAction
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copy
Copy an expression. This makes a deep copy.- Overrides:
copy
in classSourceDocument
- Parameters:
rebindings
- variables that need to be re-bound- Returns:
- the copy of the original expression
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push
Evaluate the instruction in push mode- Specified by:
push
in interfacePusher
- Overrides:
push
in classSourceDocument
- Parameters:
output
- the final destination for the output of the instructioncontext
- the evaluation context- Throws:
XPathException
- in the event of a failureQuitParsingException
- if there was an early exit, that is, if the instruction was evaluated without reading the input to completion
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iterate
Return 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 implementation uses two threads: the instruction is evaluated in push mode in a child thread (using the process() method), putting its results on a queue, from which this method reads them.- Overrides:
iterate
in classInstruction
- 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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process
Process the instruction, without returning any tail calls- Overrides:
process
in classInstruction
- Parameters:
output
- the destination for the resultcontext
- The dynamic context, giving access to the current node- Throws:
XPathException
- if a dynamic error occurs
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getExportTag
- Overrides:
getExportTag
in classSourceDocument
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getElaborator
Description copied from class:Expression
Make an elaborator for this expression- Overrides:
getElaborator
in classSourceDocument
- Returns:
- an appropriate
Elaborator
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