net.sf.saxon.instruct
Class CopyOf

java.lang.Object
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  +--net.sf.saxon.instruct.Instruction
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        +--net.sf.saxon.instruct.ExprInstruction
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              +--net.sf.saxon.instruct.CopyOf

All Implemented Interfaces:

Expression, Instr, Locatable, java.io.Serializable, javax.xml.transform.SourceLocator

public class CopyOf

extends ExprInstruction

An xsl:copy-of element in the stylesheet.

See Also:

Serialized Form

Field Summary

 

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

children

 

Constructor Summary

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

 

Method Summary
Expression	analyze(StaticContext env)           Perform static analysis of an expression and its subexpressions.
protected static void	copyAttribute(NodeInfo source, SchemaType schemaType, int validation, Controller controller)
void	display(int level, NamePool pool)           Diagnostic print of expression structure.
boolean	effectiveBooleanValue(XPathContext context)           Get the effective boolean value of the expression.
Item	evaluateItem(XPathContext context)           Return the first item if there is one, or null if not
int	getCardinality()           Determine the static cardinality of the expression.
int	getDependencies()           Determine which aspects of the context the expression depends on.
java.lang.String	getInstructionName()           Get the name of this instruction, for diagnostics and tracing
ItemType	getItemType()           Determine the data type of the expression, if possible.
int	getSpecialProperties()           Get the static properties of this expression (other than its type).
Expression[]	getSubExpressions()           Get the immediate sub-expressions of this expression.
protected  void	getXPathExpressions(java.util.List list)           Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)
SequenceIterator	iterate(XPathContext context)           Return an Iterator to iterate over the values of a sequence.
TailCall	processLeavingTail(XPathContext context)           Process this xsl:copy-of instruction
protected  void	promoteInst(PromotionOffer offer)           Handle promotion offers, that is, non-local tree rewrites.
void	setRequireDocumentOrElement(boolean requireDocumentOrElement)           For XQuery, the operand (select) must be a single element or document node.
void	setValidationContext(ValidationContext validationContext)           Set the validation context
Expression	simplify()           Simplify an expression.

 

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

evaluateAsString, promote

 

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

assembleParams, assembleTunnelParams, displayChildren, dynamicError, dynamicError, getChildren, getColumnNumber, getExecutable, getInstructionNamespace, getLineNumber, getPublicId, getSourceLocator, getSystemId, process, processChildren, processChildrenLeavingTail, recoverableError, setChildren, setExecutable, setSourceLocation

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

CopyOf

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

getInstructionName

public java.lang.String getInstructionName()

Get the name of this instruction, for diagnostics and tracing

Specified by:

getInstructionName in class Instruction

setRequireDocumentOrElement

public void setRequireDocumentOrElement(boolean requireDocumentOrElement)

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

Parameters:

requireDocumentOrElement -

setValidationContext

public void setValidationContext(ValidationContext validationContext)

Set the validation context

Parameters:

validationContext -

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws javax.xml.transform.TransformerException

Process this xsl:copy-of instruction

Specified by:

processLeavingTail in interface Instr

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

javax.xml.transform.TransformerException

copyAttribute

protected static void copyAttribute(NodeInfo source,
                                    SchemaType schemaType,
                                    int validation,
                                    Controller controller)
                             throws javax.xml.transform.TransformerException

javax.xml.transform.TransformerException

simplify

public Expression simplify()
                    throws XPathException

Description copied from class: ExprInstruction

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 interface Expression

Overrides:

simplify in class ExprInstruction

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

getItemType

public ItemType getItemType()

Description copied from interface: Expression

Determine the data type of the expression, if possible. All expression return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.

This method should always return a result, though it may be the best approximation that is available at the time.

Specified by:

getItemType in interface Expression

Overrides:

getItemType in class Instruction

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

getCardinality

public int getCardinality()

Description copied from interface: 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.

This method should always return a result, though it may be the best approximation that is available at the time.

Specified by:

getCardinality in interface Expression

Overrides:

getCardinality in class Instruction

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: ExprInstruction

Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as StaticProperty.DEPENDS_ON_CONTEXT_ITEM and StaticProperty.DEPENDS_ON_CURRENT_ITEM. 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.

Specified by:

getDependencies in interface Expression

Overrides:

getDependencies in class ExprInstruction

Returns:

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

getSpecialProperties

public int getSpecialProperties()

Description copied from class: ExprInstruction

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.

Specified by:

getSpecialProperties in interface Expression

Overrides:

getSpecialProperties in class ExprInstruction

Returns:

a set of flags indicating static properties of this expression

promoteInst

protected void promoteInst(PromotionOffer offer)
                    throws XPathException

Description copied from class: ExprInstruction

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

Specified by:

promoteInst in class ExprInstruction

Parameters:

offer - The type of rewrite being offered

Throws:

XPathException

getXPathExpressions

protected void getXPathExpressions(java.util.List list)

Description copied from class: ExprInstruction

Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction)

Specified by:

getXPathExpressions in class ExprInstruction

Parameters:

list - A list to be populated with the list of XPath expressions

analyze

public Expression analyze(StaticContext env)
                   throws XPathException

Perform static analysis of an expression and its subexpressions.

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 will only be accurately known if they have been explicitly declared.

Specified by:

analyze in interface Expression

Overrides:

analyze in class ExprInstruction

Parameters:

env - the static context of the expression

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)

display

public void display(int level,
                    NamePool pool)

Diagnostic print of expression structure. The expression is written to the System.err output stream

Parameters:

level - indentation level for this expression

getSubExpressions

public Expression[] getSubExpressions()

Description copied from class: ExprInstruction

Get the immediate sub-expressions of this expression.

Specified by:

getSubExpressions in interface Expression

Overrides:

getSubExpressions in class ExprInstruction

Returns:

an array containing the sub-expressions of this expression

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 Expression

Overrides:

evaluateItem in class ExprInstruction

Parameters:

context -

Returns:

the result of evaluating the instruction

Throws:

XPathException

effectiveBooleanValue

public boolean effectiveBooleanValue(XPathContext context)
                              throws XPathException

Description copied from class: ExprInstruction

Get the effective boolean value of the expression. This returns false if the value is the empty sequence, a zero-length string, a number equal to zero, or the boolean false. Otherwise it returns true.

Specified by:

effectiveBooleanValue in interface Expression

Overrides:

effectiveBooleanValue in class ExprInstruction

Parameters:

context - The context in which the expression is to be evaluated

Returns:

the effective boolean value

Throws:

XPathException - if any dynamic error occurs evaluating the expression

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Description copied from class: ExprInstruction

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 Expression

Overrides:

iterate in class ExprInstruction

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