Interface XPathContext

All Known Implementing Classes:
EarlyEvaluationContext, XPathContextMajor, XPathContextMinor

public interface XPathContext
This class represents a context in which an XPath expression is evaluated.
  • Method Details

    • newContext

      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
      Returns:
      a new context, created as a copy of this context
    • newCleanContext

      XPathContextMajor newCleanContext()
      Construct a new context without copying (used for the context in a function call)
      Returns:
      a new clean context
    • newMinorContext

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

      ParameterSet getLocalParameters()
      Get the local (non-tunnel) parameters that were passed to the current function or template
      Returns:
      a ParameterSet containing the local parameters
    • getTunnelParameters

      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
    • setOrigin

      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.
      Parameters:
      expr - the expression that created this context object
    • setOriginatingConstructType

      void setOriginatingConstructType(int loc)
      Set the type of creating expression (for use in diagnostics). When a new context is created, either this method or setOrigin(net.sf.saxon.trace.InstructionInfo) should be called.
      Parameters:
      loc - The originating location: the argument must be one of the integer constants in class Location
    • getOrigin

      InstructionInfo getOrigin()
      Get information about the creating expression or other construct.
      Returns:
      information about the creating expression
    • getOriginatingConstructType

      int getOriginatingConstructType()
      Get the type of location from which this context was created.
      Returns:
      the type of location. (The integer codes that are used are often fingerprints of instruction names, but not always. For details of the codes, see the standard trace listener which interprets them)
    • getController

      Controller getController()
      Get the Controller. May return null when running outside XSLT or XQuery
      Returns:
      the controller for this query or transformation
    • getConfiguration

      Configuration getConfiguration()
      Get the Configuration
      Returns:
      the Saxon configuration object
    • getNamePool

      NamePool getNamePool()
      Get the Name Pool
      Returns:
      the name pool
    • setCaller

      void setCaller(XPathContext caller)
      Set the calling XPathContext
      Parameters:
      caller - the XPathContext of the calling expression
    • getCaller

      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.
      Returns:
      the XPathContext of the calling expression
    • setCurrentIterator

      void setCurrentIterator(SequenceIterator iter)
      Set a new sequence iterator.
      Parameters:
      iter - the current iterator. The context item, position, and size are determined by reference to the current iterator.
    • getCurrentIterator

      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).
    • getContextPosition

      int getContextPosition() throws XPathException
      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
    • getContextItem

      Item getContextItem()
      Get the context item
      Returns:
      the context item, or null if the context item is undefined
    • getLast

      int getLast() throws XPathException
      Get the context size (the position of the last item in the current node list)
      Returns:
      the context size
      Throws:
      XPathException - if the context position is undefined
    • isAtLast

      boolean isAtLast() throws XPathException
      Determine whether the context position is the same as the context size that is, whether position()=last(). In many cases this has better performance than a direct comparison, because it does not require reading to the end of the sequence.
      Returns:
      true if the context position is the same as the context size.
      Throws:
      XPathException
    • getCollation

      StringCollator getCollation(String name) throws XPathException
      Get a named collation
      Parameters:
      name - the name (URI) of the required collation
      Returns:
      a StringCollator representing the collation
      Throws:
      XPathException - if the collation is not recognized
    • getDefaultCollation

      StringCollator getDefaultCollation()
      Get the default collation
      Returns:
      a StringCollator representing the default collation
    • useLocalParameter

      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
      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
      Throws:
      XPathException
    • getStackFrame

      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.
    • evaluateLocalVariable

      ValueRepresentation evaluateLocalVariable(int slotnumber)
      Get the value of a local variable, identified by its slot number
      Parameters:
      slotnumber - the slot number allocated at compile time to the variable, which identifies its position within the local stack frame
      Returns:
      the value of the variable.
    • setLocalVariable

      void setLocalVariable(int slotnumber, ValueRepresentation value)
      Set the value of a local variable, identified by its slot number
      Parameters:
      slotnumber - the slot number allocated at compile time to the variable, which identifies its position within the local stack frame
      value - the value of the variable
    • changeOutputDestination

      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.
      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 not
      hostLanguage - typically XSLT or XQuery
      validation - validation mode: strict, lax, preserve, or strip
      schemaType - type against which the output must be validated
      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
    • setTemporaryReceiver

      void setTemporaryReceiver(SequenceReceiver out)
      Set the SequenceReceiver to which output is to be written, marking it as a temporary (non-final) output destination.
      Parameters:
      out - The SequenceReceiver to be used
    • setReceiver

      void setReceiver(SequenceReceiver receiver)
      Change the SequenceReceiver to which output is written
      Parameters:
      receiver - the SequenceReceiver to be used
    • getReceiver

      SequenceReceiver getReceiver()
      Get the Receiver to which output is currently being written.
      Returns:
      the current SequenceReceiver
    • getCurrentMode

      Mode getCurrentMode()
      Get the current mode.
      Returns:
      the current mode
    • getCurrentTemplateRule

      Rule getCurrentTemplateRule()
      Get the current template rule. This is used to support xsl:apply-imports and xsl:next-match
      Returns:
      the current template rule
    • getCurrentGroupIterator

      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
    • getCurrentRegexIterator

      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
    • getCurrentDateTime

      DateTimeValue getCurrentDateTime() throws NoDynamicContextException
      Get the current date and time
      Returns:
      the current date and time. All calls within a single query or transformation will return the same value
      Throws:
      NoDynamicContextException
    • getImplicitTimezone

      int getImplicitTimezone() throws NoDynamicContextException
      Get the implicit timezone
      Returns:
      the implicit timezone. This will be the timezone of the current date and time, and all calls within a single query or transformation will return the same value. The result is expressed as an offset from UTC in minutes.
      Throws:
      NoDynamicContextException
    • iterateStackFrames

      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