net.sf.saxon.expr.instruct

Class CopyOf

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.instruct.Instruction

net.sf.saxon.expr.instruct.CopyOf

All Implemented Interfaces:

TailCallReturner, ValidatingInstruction, IdentityComparable

public class CopyOf
extends Instruction
implements ValidatingInstruction

An xsl:copy-of element in the stylesheet.

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
CopyOf(Expression select, boolean copyNamespaces, int validation, SchemaType schemaType, boolean rejectDuplicateAttributes) Create an xsl:copy-of instruction (also used in XQuery for implicit copying)

Method Summary

Methods

Modifier and Type	Method and Description
PathMap.PathMapNodeSet	addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) Add a representation of this expression to a PathMap.
static String	computeNewBaseUri(NodeInfo source, String staticBaseURI)
Expression	copy() Copy an expression.
boolean	createsNewNodes() Determine whether this instruction creates new nodes.
void	export(ExpressionPresenter out) Diagnostic print of expression structure.
int	getCardinality() Determine the static cardinality of the expression.
int	getDependencies() Determine which aspects of the context the expression depends on.
ExpressionCompiler	getExpressionCompiler() Return the compiler of the CopyOf expression
int	getImplementationMethod() An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
int	getInstructionNameCode() Get the name of this instruction, for diagnostics and tracing
ItemType	getItemType() Get the item type of the items returned by evaluating this instruction
SchemaType	getSchemaType() Get the schema type to be used for validation
Expression	getSelect()
CopyOfAdjunct	getStreamingAdjunct() Get a class that supports streamed evaluation of this expression
int	getValidationAction() Get the validation mode
boolean	isCopyAccumulators() Ask whether accumulator values should be copied from the source document
boolean	isCopyForUpdate() Ask whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)
boolean	isCopyNamespaces() Ask whether namespaces are to be copied or not
boolean	isDocumentOrElementRequired() Test whether this expression requires a document or element node
boolean	isValidating() Test if the instruction is doing validation
SequenceIterator	iterate(XPathContext context) Return an Iterator to iterate over the values of a sequence.
Iterable<Operand>	operands() Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.
Expression	optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Perform optimisation of an expression and its subexpressions.
TailCall	processLeavingTail(XPathContext context) Process this xsl:copy-of instruction
protected void	promoteChildren(PromotionOffer offer) Handle promotion offers, that is, non-local tree rewrites.
void	setCopyAccumulators(boolean copy) Say whether accumulator values should be copied from the source document
void	setCopyForUpdate(boolean forUpdate) Set whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)
void	setCopyLineNumbers(boolean copy) Set whether line numbers are to be copied from the source to the result.
void	setReadOnce(boolean b) Set the "saxon:read-once" optimization mode
void	setRequireDocumentOrElement(boolean requireDocumentOrElement) For XQuery, the operand (select) must be a single element or document node.
void	setSchemaAware(boolean schemaAware) Set the "is schema aware" property
void	setSelect(Expression select) Set the select expression
Expression	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Perform type checking of an expression and its subexpressions.
static SimpleType	validateAttribute(NodeInfo source, SimpleType schemaType, int validation, XPathContext context) Validate an attribute node and return the type annotation to be used

Methods inherited from class net.sf.saxon.expr.instruct.Instruction

assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getExpressionName, getInstructionName, getNetCost, getSourceLocator, isXSLT, main, process, toStreamingPattern

Methods inherited from class net.sf.saxon.expr.Expression

adoptChildExpression, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getConfiguration, getCost, getEvaluationMethod, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLocation, getObjectName, getPackageData, getParentExpression, getPosture, getPostureAndSweepIfKnown, getProperties, getProperty, getRetainedStaticContext, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStreamability, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, optimizeForType, promote, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setFiltered, setFlattened, setLocation, setParentExpression, setPostureAndSweep, setRetainedStaticContext, setRetainedStaticContextLocally, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeCheckChildren, typeError, unordered

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CopyOf

public CopyOf(Expression select,
      boolean copyNamespaces,
      int validation,
      SchemaType schemaType,
      boolean rejectDuplicateAttributes)

Create an xsl:copy-of instruction (also used in XQuery for implicit copying)

Parameters:

select - expression that selects the nodes to be copied

copyNamespaces - true if namespaces are to be copied

validation - validation mode for the result tree

schemaType - schema type for validating the result tree

rejectDuplicateAttributes - true if duplicate attributes are to be rejected (XQuery). False if duplicates are handled by discarding all but the first (XSLT).

Method Detail

getSelect

public Expression getSelect()

setSelect

public void setSelect(Expression select)

Set the select expression

Parameters:

select - the new select expression

operands

public Iterable<Operand> operands()

Description copied from class: Expression

Get 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.

Specified by:

operands in class Instruction

Returns:

an iterator containing the sub-expressions of this expression

getValidationAction

public int getValidationAction()

Get the validation mode

Specified by:

getValidationAction in interface ValidatingInstruction

Returns:

the validation mode

isValidating

public boolean isValidating()

Test if the instruction is doing validation

Returns:

true if it is

getSchemaType

public SchemaType getSchemaType()

Get the schema type to be used for validation

Specified by:

getSchemaType in interface ValidatingInstruction

Returns:

the schema type, or null if not validating against a type

setSchemaAware

public void setSchemaAware(boolean schemaAware)

Set the "is schema aware" property

Parameters:

schemaAware - true if schema awareness is enabled

setReadOnce

public void setReadOnce(boolean b)

Set the "saxon:read-once" optimization mode

Parameters:

b - true to enable the optimization

setCopyLineNumbers

public void setCopyLineNumbers(boolean copy)

Set whether line numbers are to be copied from the source to the result. Default is false.

Parameters:

copy - true if line numbers are to be copied

createsNewNodes

public final boolean createsNewNodes()

Determine whether this instruction creates new nodes. The result depends on the type of the select expression.

Overrides:

createsNewNodes in class Instruction

Returns:

true if the instruction creates new nodes (or if it can't be proved that it doesn't)

getInstructionNameCode

public int getInstructionNameCode()

Get the name of this instruction, for diagnostics and tracing

Overrides:

getInstructionNameCode in class Instruction

Returns:

a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace

setRequireDocumentOrElement

public void setRequireDocumentOrElement(boolean requireDocumentOrElement)

For XQuery, the operand (select) must be a single element or document node.

Parameters:

requireDocumentOrElement - true if the argument must be a single element or document node

isDocumentOrElementRequired

public boolean isDocumentOrElementRequired()

Test whether this expression requires a document or element node

Returns:

true if this expression requires the value of the argument to be a document or element node, false if there is no such requirement

setCopyForUpdate

public void setCopyForUpdate(boolean forUpdate)

Set whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)

Parameters:

forUpdate - true if this copy is being created to support an update

isCopyForUpdate

public boolean isCopyForUpdate()

Ask whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)

Returns:

true if this copy is being created to support an update

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. This implementation provides both iterate() and process() methods natively.

Overrides:

getImplementationMethod in class Instruction

Returns:

the implementation method, for example Expression.ITERATE_METHOD or Expression.EVALUATE_METHOD or Expression.PROCESS_METHOD

isCopyNamespaces

public boolean isCopyNamespaces()

Ask whether namespaces are to be copied or not

Returns:

true if namespaces are to be copied (the default)

setCopyAccumulators

public void setCopyAccumulators(boolean copy)

Say whether accumulator values should be copied from the source document

Parameters:

copy - true if values should be copied

isCopyAccumulators

public boolean isCopyAccumulators()

Ask whether accumulator values should be copied from the source document

Returns:

true if values should be copied

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Specified by:

copy in class Expression

Returns:

the copy of the original expression

getItemType

public ItemType getItemType()

Description copied from class: Instruction

Get the item type of the items returned by evaluating this instruction

Overrides:

getItemType in class Instruction

Returns:

the static item type of the instruction

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 class Expression

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).

getDependencies

public int getDependencies()

Description copied from class: Expression

Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and XPathContext.CURRENT_NODE. The default implementation combines the intrinsic dependencies of this expression with the dependencies of the subexpressions, computed recursively. This is overridden for expressions such as FilterExpression where a subexpression's dependencies are not necessarily inherited by the parent expression.

Overrides:

getDependencies in class Expression

Returns:

a set of bit-significant flags identifying the dependencies of the expression

promoteChildren

protected void promoteChildren(PromotionOffer offer)
                        throws XPathException

Description copied from class: Instruction

Handle promotion offers, that is, non-local tree rewrites.

Overrides:

promoteChildren in class Instruction

Parameters:

offer - The type of rewrite being offered

Throws:

XPathException - if an error occurs

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                   ContextItemStaticInfo contextInfo)
                     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.

Overrides:

typeCheck in class Expression

Parameters:

visitor - an expression visitor

contextInfo - 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)

optimize

public Expression optimize(ExpressionVisitor visitor,
                  ContextItemStaticInfo 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 class Expression

Parameters:

visitor - an expression visitor

contextItemType - 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 to Type.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)

export

public void export(ExpressionPresenter out)

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

export in class Expression

Parameters:

out - the expression presenter used to display the structure

getStreamingAdjunct

public CopyOfAdjunct getStreamingAdjunct()

Get a class that supports streamed evaluation of this expression

Overrides:

getStreamingAdjunct in class Expression

Returns:

the relevant StreamingAdjunct, or null if none is available

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 class Expression

Parameters:

pathMap - the PathMap to which the expression should be added

pathMapNodeSet - 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.

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Process this xsl:copy-of instruction

Specified by:

processLeavingTail in interface TailCallReturner

Specified by:

processLeavingTail in class Instruction

Parameters:

context - the dynamic context for the transformation

Returns:

null - this implementation of the method never returns a TailCall

Throws:

XPathException - if a dynamic error occurs during the evaluation of the instruction

computeNewBaseUri

public static String computeNewBaseUri(NodeInfo source,
                       String staticBaseURI)

validateAttribute

public static SimpleType validateAttribute(NodeInfo source,
                           SimpleType schemaType,
                           int validation,
                           XPathContext context)
                                    throws XPathException

Validate an attribute node and return the type annotation to be used

Parameters:

source - the node to be copied

schemaType - the simple type against which the value is to be validated, if any

validation - one of preserve, strip, strict, lax

context - the dynamic context

Returns:

the type annotation to be used for the attribute

Throws:

XPathException - if the attribute is not valid

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Description copied from class: Instruction

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 default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.

Overrides:

iterate in class Instruction

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

getExpressionCompiler

public ExpressionCompiler getExpressionCompiler()

Return the compiler of the CopyOf expression

Overrides:

getExpressionCompiler in class Expression

Returns:

the relevant ExpressionCompiler