net.sf.saxon.expr

Class EarlyEvaluationContext

public class EarlyEvaluationContext extends Object implements XPathContext, Serializable

This class is an implementation of XPathContext used when evaluating constant sub-expressions at compile time.
Constructor Summary
EarlyEvaluationContext(Configuration config, CollationMap map)
Create an early evaluation context, used for evaluating constant expressions at compile time
Method Summary
voidchangeOutputDestination(Receiver receiver, boolean isFinal, int validation, SchemaType schemaType)
Set a new output destination, supplying the output format details.
ValueRepresentationevaluateLocalVariable(int slotnumber)
Get the value of a local variable, identified by its slot number
XPathContextgetCaller()
Get the calling XPathContext (the next one down the stack).
StringCollatorgetCollation(String name)
Get a named collation
ConfigurationgetConfiguration()
Get the Configuration
ItemgetContextItem()
Get the context item
intgetContextPosition()
Get the context position (the position of the context item)
ControllergetController()
Get the Controller.
DateTimeValuegetCurrentDateTime()
Get the current date and time.
XPathExceptiongetCurrentException()
Get the current exception (in saxon:catch)
GroupIteratorgetCurrentGroupIterator()
Get the current group iterator.
SequenceIteratorgetCurrentIterator()
Get the current iterator.
ModegetCurrentMode()
Get the current mode.
RegexIteratorgetCurrentRegexIterator()
Get the current regex iterator.
RulegetCurrentTemplateRule()
Get the current template.
intgetImplicitTimezone()
Get the implicit timezone, as a positive or negative offset from UTC in minutes.
intgetLast()
Get the context size (the position of the last item in the current node list)
ParameterSetgetLocalParameters()
Get the local (non-tunnel) parameters that were passed to the current function or template
NamePoolgetNamePool()
Get the Name Pool
InstructionInfogetOrigin()
Get information about the creating expression or other construct.
intgetOriginatingConstructType()
Get the type of location from which this context was created.
SequenceReceivergetReceiver()
Get the Receiver to which output is currently being written.
StackFramegetStackFrame()
Get a reference to the local stack frame for variables.
ParameterSetgetTunnelParameters()
Get the tunnel parameters that were passed to the current function or template.
booleanisAtLast()
Determine whether the context position is the same as the context size that is, whether position()=last()
IteratoriterateStackFrames()
Get the context stack.
XPathContextMajornewCleanContext()
Construct a new context without copying (used for the context in a function call)
XPathContextMajornewContext()
Construct a new context as a copy of another.
XPathContextMinornewMinorContext()
Construct a new minor context.
voidsetCaller(XPathContext caller)
Set the calling XPathContext
voidsetCurrentIterator(SequenceIterator iter)
Set a new sequence iterator.
voidsetLocalVariable(int slotnumber, ValueRepresentation value)
Set the value of a local variable, identified by its slot number
voidsetOrigin(InstructionInfo expr)
Set the creating expression (for use in diagnostics).
voidsetOriginatingConstructType(int loc)
Set the type of creating expression (for use in diagnostics).
voidsetReceiver(SequenceReceiver receiver)
Change the Receiver to which output is written
voidsetTemporaryReceiver(SequenceReceiver out)
Set the receiver to which output is to be written, marking it as a temporary (non-final) output destination.
intuseLocalParameter(StructuredQName qName, LocalParam binding, boolean isTunnel)
Use local parameter.

Constructor Detail

EarlyEvaluationContext

public EarlyEvaluationContext(Configuration config, CollationMap map)
Create an early evaluation context, used for evaluating constant expressions at compile time

Parameters: config the Saxon configuration map the available collations

Method Detail

changeOutputDestination

public void changeOutputDestination(Receiver receiver, boolean isFinal, int validation, SchemaType schemaType)
Set a new output destination, supplying the output format details.
Note that it is the caller's responsibility to close the Writer after use.

Parameters: isFinal true if the destination is a final result tree (either the principal output or a secondary result tree); false if it is a temporary tree, xsl:attribute, etc.

Throws: net.sf.saxon.trans.XPathException if any dynamic error occurs; and specifically, if an attempt is made to switch to a final output destination while writing a temporary tree or sequence

evaluateLocalVariable

public ValueRepresentation evaluateLocalVariable(int slotnumber)
Get the value of a local variable, identified by its slot number

getCaller

public XPathContext getCaller()
Get the calling XPathContext (the next one down the stack). This will be null if unknown, or if the bottom of the stack has been reached.

getCollation

public StringCollator getCollation(String name)
Get a named collation

getConfiguration

public Configuration getConfiguration()
Get the Configuration

getContextItem

public Item getContextItem()
Get the context item

Returns: the context item, or null if the context item is undefined

getContextPosition

public int getContextPosition()
Get the context position (the position of the context item)

Returns: the context position (starting at one)

Throws: XPathException if the context position is undefined

getController

public Controller getController()
Get the Controller. May return null when running outside XSLT or XQuery

getCurrentDateTime

public DateTimeValue getCurrentDateTime()
Get the current date and time. This implementation always throws a NoDynamicContextException.

Returns: the current date and time. All calls within a single query or transformation will return the same value

getCurrentException

public XPathException getCurrentException()
Get the current exception (in saxon:catch)

Returns: the current exception, or null if there is none defined

getCurrentGroupIterator

public GroupIterator getCurrentGroupIterator()
Get the current group iterator. This supports the current-group() and current-grouping-key() functions in XSLT 2.0

Returns: the current grouped collection

getCurrentIterator

public SequenceIterator getCurrentIterator()
Get the current iterator. This encapsulates the context item, context position, and context size.

Returns: the current iterator, or null if there is no current iterator (which means the context item, position, and size are undefined).

getCurrentMode

public Mode getCurrentMode()
Get the current mode.

Returns: the current mode

getCurrentRegexIterator

public RegexIterator getCurrentRegexIterator()
Get the current regex iterator. This supports the functionality of the regex-group() function in XSLT 2.0.

Returns: the current regular expressions iterator

getCurrentTemplateRule

public Rule getCurrentTemplateRule()
Get the current template. This is used to support xsl:apply-imports

Returns: the current template

getImplicitTimezone

public int getImplicitTimezone()
Get the implicit timezone, as a positive or negative offset from UTC in minutes. The range is -14hours to +14hours. This implementation always throws a NoDynamicContextException.

Returns: the implicit timezone, as an offset from UTC in minutes

getLast

public int getLast()
Get the context size (the position of the last item in the current node list)

Returns: the context size

Throws: net.sf.saxon.trans.XPathException if the context position is undefined

getLocalParameters

public ParameterSet getLocalParameters()
Get the local (non-tunnel) parameters that were passed to the current function or template

Returns: a ParameterSet containing the local parameters

getNamePool

public NamePool getNamePool()
Get the Name Pool

getOrigin

public InstructionInfo getOrigin()
Get information about the creating expression or other construct.

getOriginatingConstructType

public int getOriginatingConstructType()
Get the type of location from which this context was created.

getReceiver

public SequenceReceiver getReceiver()
Get the Receiver to which output is currently being written.

Returns: the current Receiver

getStackFrame

public StackFrame getStackFrame()
Get a reference to the local stack frame for variables. Note that it's the caller's job to make a local copy of this. This is used for creating a Closure containing a retained copy of the variables for delayed evaluation.

Returns: array of variables.

getTunnelParameters

public ParameterSet getTunnelParameters()
Get the tunnel parameters that were passed to the current function or template. This includes all active tunnel parameters whether the current template uses them or not.

Returns: a ParameterSet containing the tunnel parameters

isAtLast

public boolean isAtLast()
Determine whether the context position is the same as the context size that is, whether position()=last()

iterateStackFrames

public Iterator iterateStackFrames()
Get the context stack. This method returns an iterator whose items are instances of ContextStackFrame, starting with the top-most stackframe and ending at the point the query or transformation was invoked by a calling application.

Returns: an iterator over a copy of the run-time call stack

newCleanContext

public XPathContextMajor newCleanContext()
Construct a new context without copying (used for the context in a function call)

newContext

public XPathContextMajor newContext()
Construct a new context as a copy of another. The new context is effectively added to the top of a stack, and contains a pointer to the previous context

newMinorContext

public XPathContextMinor newMinorContext()
Construct a new minor context. A minor context can only hold new values of the focus (currentIterator) and current output destination.

setCaller

public void setCaller(XPathContext caller)
Set the calling XPathContext

setCurrentIterator

public void setCurrentIterator(SequenceIterator iter)
Set a new sequence iterator.

setLocalVariable

public void setLocalVariable(int slotnumber, ValueRepresentation value)
Set the value of a local variable, identified by its slot number

setOrigin

public void setOrigin(InstructionInfo expr)
Set the creating expression (for use in diagnostics). The origin is generally set to "this" by the object that creates the new context. It's up to the debugger to determine whether this information is useful. Where possible, the object will be an Expression, allowing information about the calling instruction to be obtained.

setOriginatingConstructType

public void setOriginatingConstructType(int loc)
Set the type of creating expression (for use in diagnostics). When a new context is created, either this method or XPathContext should be called.

Parameters: loc The originating location: the argument must be one of the integer constants in class Location

setReceiver

public void setReceiver(SequenceReceiver receiver)
Change the Receiver to which output is written

setTemporaryReceiver

public void setTemporaryReceiver(SequenceReceiver out)
Set the receiver to which output is to be written, marking it as a temporary (non-final) output destination.

Parameters: out The SequenceOutputter to be used

useLocalParameter

public int useLocalParameter(StructuredQName qName, LocalParam binding, boolean isTunnel)
Use local parameter. This is called when a local xsl:param element is processed. If a parameter of the relevant name was supplied, it is bound to the xsl:param element. Otherwise the method returns false, so the xsl:param default will be evaluated

Parameters: qName The fingerprint of the parameter name binding The XSLParam element to bind its value to isTunnel True if a tunnel parameter is required, else false

Returns: true if a parameter of this name was supplied, false if not