Class ParentNodeConstructor
- java.lang.Object
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- net.sf.saxon.expr.Expression
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- net.sf.saxon.expr.instruct.Instruction
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- net.sf.saxon.expr.instruct.ParentNodeConstructor
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,LocationProvider
,SaxonLocator
,DivisibleInstruction
,TailCallReturner
,ValidatingInstruction
,InstructionInfo
,org.xml.sax.Locator
- Direct Known Subclasses:
DocumentInstr
,ElementCreator
public abstract class ParentNodeConstructor extends Instruction implements DivisibleInstruction, ValidatingInstruction
An abstract class to act as a common parent for instructions that create element nodes and document nodes.- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected Expression
content
protected boolean
preservingTypes
Flag set to true if validation=preserve and no schema type supplied for validation; also true when validation="strip" if there is no need to physically strip type annotations(package private) int
validation
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Fields inherited from class net.sf.saxon.expr.Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD
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Constructor Summary
Constructors Constructor Description ParentNodeConstructor()
Create a document or element node constructor instruction
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description PathMap.PathMapNodeSet
addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.protected abstract void
checkContentSequence(StaticContext env)
Check that the child instructions don't violate any obvious constraints for this kind of nodeint
computeCardinality()
Get the cardinality of the sequence returned by evaluating this instructionboolean
createsNewNodes()
Determine whether this instruction creates new nodes.java.lang.String
getBaseURI()
Get the static base URI of the instructionint
getCardinality()
Determine the static cardinality of the expression.Expression
getContentExpression()
Get the expression that constructs the content of the elementSchemaType
getSchemaType()
Get the schema type chosen for validation; null if not definedint
getValidationAction()
Get the validation mode for this instructionboolean
isLazyConstruction()
Establish whether lazy construction is to be usedboolean
isNamespaceSensitive()
Determine whether the schema type is namespace sensitive.boolean
isPreservingTypes()
Determine whether this elementCreator performs validation or strips type annotationsjava.util.Iterator<Expression>
iterateSubExpressions()
Get the immediate sub-expressions of this expression.Expression
optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions.protected void
promoteInst(PromotionOffer offer)
Handle promotion offers, that is, non-local tree rewrites.boolean
replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpressionvoid
setBaseURI(java.lang.String uri)
Set the static base URI of the instructionvoid
setContentExpression(Expression content)
Set the expression that constructs the content of the elementvoid
setLazyConstruction(boolean lazy)
Indicate that lazy construction should (or should not) be used.void
setNoNeedToStrip()
Set that the newly constructed node and everything underneath it will automatically be untyped, without any need to physically remove type annotations, even though validation=STRIP is set.void
setSchemaType(SchemaType type)
Set the schema type to be used for validationvoid
setValidationAction(int mode, SchemaType schemaType)
Set the validation mode for the new document or element nodeExpression
simplify(ExpressionVisitor visitor)
Simplify an expression.Expression
typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)
Perform type checking of an expression and its subexpressions.(package private) void
verifyLazyConstruction()
Check that lazy construction is possible for this element-
Methods inherited from class net.sf.saxon.expr.instruct.Instruction
assembleParams, assembleTunnelParams, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getExpressionName, getImplementationMethod, getInstructionName, getInstructionNameCode, getItemType, getIteratorFromProcessMethod, getSourceLocator, isXSLT, iterate, process, processLeavingTail, promote
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Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, copy, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, explain, getColumnNumber, getColumnNumber, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface net.sf.saxon.expr.instruct.DivisibleInstruction
processLeft, processRight
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Field Detail
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content
protected Expression content
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validation
int validation
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preservingTypes
protected boolean preservingTypes
Flag set to true if validation=preserve and no schema type supplied for validation; also true when validation="strip" if there is no need to physically strip type annotations
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Method Detail
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setBaseURI
public void setBaseURI(java.lang.String uri)
Set the static base URI of the instruction- Parameters:
uri
- the static base URI
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getBaseURI
public java.lang.String getBaseURI()
Get the static base URI of the instruction- Returns:
- the static base URI
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setLazyConstruction
public void setLazyConstruction(boolean lazy)
Indicate that lazy construction should (or should not) be used. Note that this request will be ignored if validation is required- Parameters:
lazy
- set to true if lazy construction should be used
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isLazyConstruction
public final boolean isLazyConstruction()
Establish whether lazy construction is to be used- Returns:
- true if lazy construction is to be used
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setSchemaType
public void setSchemaType(SchemaType type)
Set the schema type to be used for validation- Parameters:
type
- the type to be used for validation. (For a document constructor, this is the required type of the document element)
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getSchemaType
public SchemaType getSchemaType()
Get the schema type chosen for validation; null if not defined- Specified by:
getSchemaType
in interfaceValidatingInstruction
- Returns:
- the type to be used for validation. (For a document constructor, this is the required type of the document element)
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isNamespaceSensitive
public boolean isNamespaceSensitive()
Determine whether the schema type is namespace sensitive. The result is undefined if schemaType is null.- Returns:
- true if the schema type is namespace sensitive
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setValidationAction
public void setValidationAction(int mode, SchemaType schemaType)
Set the validation mode for the new document or element node- Parameters:
mode
- the validation mode, for exampleValidation.STRICT
schemaType
- the required type (for validation by type). Null if not validating by type
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getValidationAction
public int getValidationAction()
Get the validation mode for this instruction- Specified by:
getValidationAction
in interfaceValidatingInstruction
- Returns:
- the validation mode, for example
Validation.STRICT
orValidation.PRESERVE
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setNoNeedToStrip
public void setNoNeedToStrip()
Set that the newly constructed node and everything underneath it will automatically be untyped, without any need to physically remove type annotations, even though validation=STRIP is set.
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setContentExpression
public void setContentExpression(Expression content)
Set the expression that constructs the content of the element- Parameters:
content
- the content expression
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getContentExpression
public Expression getContentExpression()
Get the expression that constructs the content of the element- Specified by:
getContentExpression
in interfaceDivisibleInstruction
- Returns:
- the content expression
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computeCardinality
public int computeCardinality()
Get the cardinality of the sequence returned by evaluating this instruction- Overrides:
computeCardinality
in classInstruction
- Returns:
- the static cardinality
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simplify
public Expression simplify(ExpressionVisitor visitor) throws XPathException
Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.- Specified by:
simplify
in classInstruction
- Parameters:
visitor
- an expression visitor- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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typeCheck
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
Description copied from class:Expression
Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.
If the implementation returns a value other than "this", then it is required to ensure that the location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.
- Overrides:
typeCheck
in classExpression
- 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 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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checkContentSequence
protected abstract void checkContentSequence(StaticContext env) throws XPathException
Check that the child instructions don't violate any obvious constraints for this kind of node- Parameters:
env
- the static context- Throws:
XPathException
- if the check fails
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optimize
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
Description copied from class:Expression
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 classExpression
- 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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promoteInst
protected void promoteInst(PromotionOffer offer) throws XPathException
Handle promotion offers, that is, non-local tree rewrites.- Overrides:
promoteInst
in classInstruction
- Parameters:
offer
- The type of rewrite being offered- Throws:
XPathException
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iterateSubExpressions
public java.util.Iterator<Expression> iterateSubExpressions()
Get the immediate sub-expressions of this expression.- Overrides:
iterateSubExpressions
in classExpression
- Returns:
- an iterator containing the sub-expressions of this expression
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replaceSubExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpression- Overrides:
replaceSubExpression
in classExpression
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression- Returns:
- true if the original subexpression is found
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createsNewNodes
public final boolean createsNewNodes()
Determine whether this instruction creates new nodes. This implementation returns true.- Overrides:
createsNewNodes
in classInstruction
- Returns:
- true if the instruction creates new nodes (or if it can't be proved that it doesn't)
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getCardinality
public int getCardinality()
Description copied from class:Expression
Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.- Overrides:
getCardinality
in classExpression
- Returns:
- one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).
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verifyLazyConstruction
void verifyLazyConstruction()
Check that lazy construction is possible for this element
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addToPathMap
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
- Overrides:
addToPathMap
in classExpression
- Parameters:
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
- the PathMapNodeSet to which the paths embodied in this expression should be added- Returns:
- the pathMapNodeSet representing the points in the source document that are both reachable by this expression, and that represent possible results of this expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.
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isPreservingTypes
public boolean isPreservingTypes()
Determine whether this elementCreator performs validation or strips type annotations- Returns:
- false if the instruction performs validation of the constructed output or if it strips type annotations, otherwise true
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