CopyOf

java.lang.Object
- net.sf.saxon.expr.Expression
- - net.sf.saxon.instruct.Instruction
  - - net.sf.saxon.instruct.CopyOf

All Implemented Interfaces:

java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfo, org.xml.sax.Locator
```
public class CopyOf
extends Instruction
```
An xsl:copy-of element in the stylesheet.

See Also:

Serialized Form

Field Summary
- Fields inherited from class net.sf.saxon.expr.Expression
  EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

Constructors
Constructor	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

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Expression`	`copy()`	Copy an expression.
`boolean`	`createsNewNodes()`	Determine whether this instruction creates new nodes.
`Item`	`evaluateItem(XPathContext context)`	Return the first item if there is one, or null if not
`void`	`explain(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.
`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(TypeHierarchy th)`	Get the item type of the items returned by evaluating this instruction
`SchemaType`	`getSchemaType()`	Get the schema type to be used for validation
`Expression`	`getSelectExpression()`	Get the expression that selects the nodes to be copied
`int`	`getValidationMode()`	Get the validation mode
`boolean`	`isCopyForUpdate()`	Ask whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)
`boolean`	`isCopyNamespaces()`	Determine whether namespaces are to be copied or not
`boolean`	`isDocumentOrElementRequired()`	Test whether this expression requires a document or element node
`SequenceIterator`	`iterate(XPathContext context)`	Return an Iterator to iterate over the values of a sequence.
`java.util.Iterator`	`iterateSubExpressions()`	Get the immediate sub-expressions of this expression.
`Expression`	`optimize(ExpressionVisitor visitor, ItemType contextItemType)`	Perform optimisation of an expression and its subexpressions.
`TailCall`	`processLeavingTail(XPathContext context)`	Process this xsl:copy-of instruction
`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 subexpression
`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`	`setStaticBaseUri(java.lang.String base)`	Set the static base URI of the xsl:copy-of instruction
`Expression`	`simplify(ExpressionVisitor visitor)`	Simplify an expression.
`Expression`	`typeCheck(ExpressionVisitor visitor, ItemType contextItemType)`	Perform type checking of an expression and its subexpressions.

Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, findParentOf, getColumnNumber, getColumnNumber, getContainer, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError

Methods inherited from class net.sf.saxon.instruct.Instruction
assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, getConstructType, getSourceLocator, isXSLT, process, promote

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface javax.xml.transform.SourceLocator
getColumnNumber, getLineNumber, getPublicId, getSystemId

- 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
  - getSelectExpression
```
public Expression getSelectExpression()
```
    Get the expression that selects the nodes to be copied
    
    Returns:
    
    the select expression
  - getValidationMode
```
public int getValidationMode()
```
    Get the validation mode
    
    Returns:
    
    the validation mode
  - getSchemaType
```
public SchemaType getSchemaType()
```
    Get the schema type to be used for validation
    
    Returns:
    
    the schema type, or null if not validating against a type
  - setStaticBaseUri
```
public void setStaticBaseUri(java.lang.String base)
```
    Set the static base URI of the xsl:copy-of instruction
    
    Parameters:
    
    base - the static base URI
  - 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()
```
    Determine whether namespaces are to be copied or not
    
    Returns:
    
    true if namespaces are to be copied (the default)
  - 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
  - simplify
```
public Expression simplify(ExpressionVisitor visitor)
                    throws XPathException
```
    Description copied from class: Instruction
    
    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 class Instruction
    
    Parameters:
    
    visitor - an expression visitor
    
    Returns:
    
    the simplified expression
    
    Throws:
    
    XPathException - if an error is discovered during expression rewriting
  - getItemType
```
public ItemType getItemType(TypeHierarchy th)
```
    Description copied from class: Instruction
    
    Get the item type of the items returned by evaluating this instruction
    
    Overrides:
    
    getItemType in class Instruction
    
    Parameters:
    
    th - the type hierarchy cache
    
    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
  - promoteInst
```
protected void promoteInst(PromotionOffer offer)
                    throws XPathException
```
    Description copied from class: Instruction
    
    Handle promotion offers, that is, non-local tree rewrites.
    
    Overrides:
    
    promoteInst in class Instruction
    
    Parameters:
    
    offer - The type of rewrite being offered
    
    Throws:
    
    XPathException
  - typeCheck
```
public Expression typeCheck(ExpressionVisitor visitor,
                            ItemType 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 parent pointer and 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 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 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,
                           ItemType 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)
  - explain
```
public void explain(ExpressionPresenter out)
```
    Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
    
    Specified by:
    
    explain in class Expression
    
    Parameters:
    
    out - the expression presenter used to display the structure
  - iterateSubExpressions
```
public java.util.Iterator iterateSubExpressions()
```
    Description copied from class: Expression
    
    Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
    
    Overrides:
    
    iterateSubExpressions in class Expression
    
    Returns:
    
    an iterator containing the sub-expressions of this expression
  - replaceSubExpression
```
public boolean replaceSubExpression(Expression original,
                                    Expression replacement)
```
    Replace one subexpression by a replacement subexpression
    
    Overrides:
    
    replaceSubExpression in class Expression
    
    Parameters:
    
    original - the original subexpression
    
    replacement - the replacement subexpression
    
    Returns:
    
    true if the original subexpression is found
  - 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
  - evaluateItem
```
public Item evaluateItem(XPathContext context)
                  throws XPathException
```
    Return the first item if there is one, or null if not
    
    Specified by:
    
    evaluateItem in interface EvaluableItem
    
    Overrides:
    
    evaluateItem in class Instruction
    
    Parameters:
    
    context - the XPath dynamic context
    
    Returns:
    
    the result of evaluating the instruction
    
    Throws:
    
    XPathException
  - 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.
    
    Specified by:
    
    iterate in interface SequenceIterable
    
    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

Class CopyOf

Field Summary

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

Methods inherited from interface javax.xml.transform.SourceLocator

Constructor Detail

CopyOf

Method Detail

getSelectExpression

getValidationMode

getSchemaType

setStaticBaseUri

setReadOnce

setCopyLineNumbers

createsNewNodes

getInstructionNameCode

setRequireDocumentOrElement

isDocumentOrElementRequired

setCopyForUpdate

isCopyForUpdate

getImplementationMethod

isCopyNamespaces

copy

simplify

getItemType

getCardinality

getDependencies

promoteInst

typeCheck

optimize

explain

iterateSubExpressions

replaceSubExpression

processLeavingTail

evaluateItem

iterate