Class Assign

  extended by net.sf.saxon.expr.Expression
      extended by net.sf.saxon.expr.instruct.Instruction
          extended by net.sf.saxon.expr.instruct.GeneralVariable
              extended by net.sf.saxon.expr.instruct.Assign
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, Binding, BindingReference, EvaluableItem, TailCallReturner, SequenceIterable, InstructionInfo, Locator

public class Assign
extends GeneralVariable
implements BindingReference

saxon:assign element in stylesheet. The saxon:assign element has mandatory attribute name and optional attribute expr. It also allows xsl:extension-element-prefixes etc.

See Also:
Serialized Form

Field Summary
Fields inherited from class net.sf.saxon.expr.instruct.GeneralVariable
evaluationMode, referenceCount, slotNumber, variableQName
Fields inherited from class net.sf.saxon.expr.Expression
Constructor Summary
Method Summary
 ValueRepresentation evaluateVariable(XPathContext context)
          Evaluate the variable (method exists only to satisfy the interface)
 void explain(ExpressionPresenter out)
          Diagnostic print of expression structure.
 void fixup(Binding binding)
          Fix up this binding reference to a binding
 int getInstructionNameCode()
          Get the name of this instruction for diagnostic and tracing purposes
 int getIntrinsicDependencies()
          Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
 TailCall processLeavingTail(XPathContext context)
          ProcessLeavingTail: called to do the real work of this instruction.
 Expression promote(PromotionOffer offer, Expression parent)
          Offer promotion for this subexpression.
 void setStaticType(SequenceType type, Value constantValue, int properties)
          Fix up the static type of this variable reference; optionally, supply a constant value for the variable.
Methods inherited from class net.sf.saxon.expr.instruct.GeneralVariable
copy, evaluateItem, getCardinality, getEvaluationMode, getItemType, getLocalSlotNumber, getRequiredType, getSelectExpression, getSelectValue, getSlotNumber, getVariableQName, init, isAssignable, isGlobal, isImplicitlyRequiredParam, isRequiredParam, isTunnelParam, iterate, iterateSubExpressions, optimize, promoteInst, replaceSubExpression, setAssignable, setImplicitlyRequiredParam, setReferenceCount, setRequiredParam, setRequiredType, setSelectExpression, setSlotNumber, setTunnel, setVariableQName, simplify, typeCheck
Methods inherited from class net.sf.saxon.expr.instruct.Instruction
assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, createsNewNodes, dynamicError, evaluateAsString, getConstructType, getExpressionName, getImplementationMethod, getInstructionName, getIteratorFromProcessMethod, getSourceLocator, isXSLT, process
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getColumnNumber, getColumnNumber, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError
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


public Assign()
Method Detail


public void setStaticType(SequenceType type,
                          Value constantValue,
                          int properties)
Description copied from interface: BindingReference
Fix up the static type of this variable reference; optionally, supply a constant value for the variable. Also supplies other static properties of the expression to which the variable is bound, for example whether it is an ordered node-set.

Specified by:
setStaticType in interface BindingReference


public void fixup(Binding binding)
Description copied from interface: BindingReference
Fix up this binding reference to a binding

Specified by:
fixup in interface BindingReference


public int getIntrinsicDependencies()
Description copied from class: Expression
Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

getIntrinsicDependencies in class Expression
a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty


public Expression promote(PromotionOffer offer,
                          Expression parent)
                   throws XPathException
Offer promotion for this subexpression. This needs careful handling in the case of saxon:assign

promote in class Instruction
offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
parent -
if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
XPathException - if any error is detected


public int getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes

getInstructionNameCode in class GeneralVariable
the name of this instruction, as a name pool name code


public TailCall processLeavingTail(XPathContext context)
                            throws XPathException
Description copied from class: Instruction
ProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.

Specified by:
processLeavingTail in interface TailCallReturner
Specified by:
processLeavingTail in class Instruction
context - The dynamic context of the transformation, giving access to the current node, the current variables, etc.
null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.


public ValueRepresentation evaluateVariable(XPathContext context)
                                     throws XPathException
Evaluate the variable (method exists only to satisfy the interface)

Specified by:
evaluateVariable in interface Binding
context - the XPath dynamic evaluation context
the result of evaluating the variable


public void explain(ExpressionPresenter out)
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

explain in class GeneralVariable
out - the expression presenter used to display the structure

Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.