net.sf.saxon.expr

Class EarlyEvaluationContext

Implemented Interfaces:
Serializable, XPathContext

public class EarlyEvaluationContext
extends java.lang.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

void
changeOutputDestination(Properties props, Result result, boolean isFinal, int hostLanguage, int validation, SchemaType schemaType)
Set a new output destination, supplying the output format details.
ValueRepresentation
evaluateLocalVariable(int slotnumber)
Get the value of a local variable, identified by its slot number
XPathContext
getCaller()
Get the calling XPathContext (the next one down the stack).
StringCollator
getCollation(String name)
Get a named collation
Configuration
getConfiguration()
Get the Configuration
Item
getContextItem()
Get the context item
int
getContextPosition()
Get the context position (the position of the context item)
Controller
getController()
Get the Controller.
DateTimeValue
getCurrentDateTime()
Get the current date and time.
GroupIterator
getCurrentGroupIterator()
Get the current group iterator.
SequenceIterator
getCurrentIterator()
Get the current iterator.
Mode
getCurrentMode()
Get the current mode.
RegexIterator
getCurrentRegexIterator()
Get the current regex iterator.
Rule
getCurrentTemplateRule()
Get the current template.
StringCollator
getDefaultCollation()
Get the default collation
int
getImplicitTimezone()
Get the implicit timezone, as a positive or negative offset from UTC in minutes.
int
getLast()
Get the context size (the position of the last item in the current node list)
ParameterSet
getLocalParameters()
Get the local (non-tunnel) parameters that were passed to the current function or template
NamePool
getNamePool()
Get the Name Pool
InstructionInfoProvider
getOrigin()
Get information about the creating expression or other construct.
int
getOriginatingConstructType()
Get the type of location from which this context was created.
SequenceReceiver
getReceiver()
Get the Receiver to which output is currently being written.
StackFrame
getStackFrame()
Get a reference to the local stack frame for variables.
ParameterSet
getTunnelParameters()
Get the tunnel parameters that were passed to the current function or template.
boolean
isAtLast()
Determine whether the context position is the same as the context size that is, whether position()=last()
XPathContextMajor
newCleanContext()
Construct a new context without copying (used for the context in a function call)
XPathContextMajor
newContext()
Construct a new context as a copy of another.
XPathContextMinor
newMinorContext()
Construct a new minor context.
void
setCaller(XPathContext caller)
Set the calling XPathContext
void
setCurrentIterator(SequenceIterator iter)
Set a new sequence iterator.
void
setLocalVariable(int slotnumber, ValueRepresentation value)
Set the value of a local variable, identified by its slot number
void
setOrigin(InstructionInfoProvider expr)
Set the creating expression (for use in diagnostics).
void
setOriginatingConstructType(int loc)
Set the type of creating expression (for use in diagnostics).
void
setReceiver(SequenceReceiver receiver)
Change the Receiver to which output is written
void
setTemporaryReceiver(SequenceReceiver out)
Set the receiver to which output is to be written, marking it as a temporary (non-final) output destination.
boolean
useLocalParameter(StructuredQName qName, LocalParam binding, boolean isTunnel)
Use local parameter.

Constructor Details

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 Details

changeOutputDestination

public void changeOutputDestination(Properties props,
                                    Result result,
                                    boolean isFinal,
                                    int hostLanguage,
                                    int validation,
                                    SchemaType schemaType)
            throws XPathException
Set a new output destination, supplying the output format details.
Note that it is the caller's responsibility to close the Writer after use.
Specified by:
changeOutputDestination in interface XPathContext
Parameters:
props - properties defining the output format
result - Details of the new output destination
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.
hostLanguage - the host language (XSLT, XQuery, XPath)
Throws:
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
Specified by:
evaluateLocalVariable in interface XPathContext

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.
Specified by:
getCaller in interface XPathContext

getCollation

public StringCollator getCollation(String name)
            throws XPathException
Get a named collation
Specified by:
getCollation in interface XPathContext

getConfiguration

public Configuration getConfiguration()
Get the Configuration
Specified by:
getConfiguration in interface XPathContext

getContextItem

public Item getContextItem()
Get the context item
Specified by:
getContextItem in interface XPathContext
Returns:
the context item, or null if the context item is undefined

getContextPosition

public int getContextPosition()
            throws XPathException
Get the context position (the position of the context item)
Specified by:
getContextPosition in interface XPathContext
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
Specified by:
getController in interface XPathContext

getCurrentDateTime

public DateTimeValue getCurrentDateTime()
            throws NoDynamicContextException
Get the current date and time. This implementation always throws a NoDynamicContextException.
Specified by:
getCurrentDateTime in interface XPathContext
Returns:
the current date and time. All calls within a single query or transformation will return the same value

getCurrentGroupIterator

public GroupIterator getCurrentGroupIterator()
Get the current group iterator. This supports the current-group() and current-grouping-key() functions in XSLT 2.0
Specified by:
getCurrentGroupIterator in interface XPathContext
Returns:
the current grouped collection

getCurrentIterator

public SequenceIterator getCurrentIterator()
Get the current iterator. This encapsulates the context item, context position, and context size.
Specified by:
getCurrentIterator in interface XPathContext
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.
Specified by:
getCurrentMode in interface XPathContext
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.
Specified by:
getCurrentRegexIterator in interface XPathContext
Returns:
the current regular expressions iterator

getCurrentTemplateRule

public Rule getCurrentTemplateRule()
Get the current template. This is used to support xsl:apply-imports
Specified by:
getCurrentTemplateRule in interface XPathContext
Returns:
the current template

getDefaultCollation

public StringCollator getDefaultCollation()
Get the default collation
Specified by:
getDefaultCollation in interface XPathContext

getImplicitTimezone

public int getImplicitTimezone()
            throws NoDynamicContextException
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.
Specified by:
getImplicitTimezone in interface XPathContext
Returns:
the implicit timezone, as an offset from UTC in minutes

getLast

public int getLast()
            throws XPathException
Get the context size (the position of the last item in the current node list)
Specified by:
getLast in interface XPathContext
Returns:
the context size
Throws:
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
Specified by:
getLocalParameters in interface XPathContext
Returns:
a ParameterSet containing the local parameters

getNamePool

public NamePool getNamePool()
Get the Name Pool
Specified by:
getNamePool in interface XPathContext

getOrigin

public InstructionInfoProvider getOrigin()
Get information about the creating expression or other construct.
Specified by:
getOrigin in interface XPathContext

getOriginatingConstructType

public int getOriginatingConstructType()
Get the type of location from which this context was created.
Specified by:
getOriginatingConstructType in interface XPathContext

getReceiver

public SequenceReceiver getReceiver()
Get the Receiver to which output is currently being written.
Specified by:
getReceiver in interface XPathContext
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.
Specified by:
getStackFrame in interface XPathContext
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.
Specified by:
getTunnelParameters in interface XPathContext
Returns:
a ParameterSet containing the tunnel parameters

isAtLast

public boolean isAtLast()
            throws XPathException
Determine whether the context position is the same as the context size that is, whether position()=last()
Specified by:
isAtLast in interface XPathContext

newCleanContext

public XPathContextMajor newCleanContext()
Construct a new context without copying (used for the context in a function call)
Specified by:
newCleanContext in interface XPathContext

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
Specified by:
newContext in interface XPathContext

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.
Specified by:
newMinorContext in interface XPathContext

setCaller

public void setCaller(XPathContext caller)
Set the calling XPathContext
Specified by:
setCaller in interface XPathContext

setCurrentIterator

public void setCurrentIterator(SequenceIterator iter)
Set a new sequence iterator.
Specified by:
setCurrentIterator in interface XPathContext

setLocalVariable

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

setOrigin

public void setOrigin(InstructionInfoProvider 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 InstructionInfoProvider, allowing information about the calling instruction to be obtained.
Specified by:
setOrigin in interface XPathContext

setOriginatingConstructType

public void setOriginatingConstructType(int loc)
Specified by:
setOriginatingConstructType in interface XPathContext
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
Specified by:
setReceiver in interface XPathContext

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.
Specified by:
setTemporaryReceiver in interface XPathContext
Parameters:
out - The SequenceOutputter to be used

useLocalParameter

public boolean useLocalParameter(StructuredQName qName,
                                 LocalParam binding,
                                 boolean isTunnel)
            throws XPathException
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
Specified by:
useLocalParameter in interface XPathContext
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