Class FieldWatch

All Implemented Interfaces:
Watch

public class FieldWatch extends PatternWatch
A FieldWatch is a class that is looking for nodes that match a field selector within a uniqueness or key constraint.
  • Constructor Details

    • FieldWatch

      public FieldWatch(SelectorWatch parentWatch, Pattern selection, AtomicSequence[] currentRow, int column)
      Create a new FieldWatch
      Parameters:
      parentWatch - The SelectorWatch to which field values should be notified
      selection - The selection (that is, the restricted XPath expression) used in this field of the constraint
      currentRow - represents the selected node whose fields are being evaluated
      column - sequence number for this field within the constraint being evaluated
  • Method Details

    • startSelectedParentNode

      public FieldChecker startSelectedParentNode(FleetingParentNode node, Location locationId) throws XPathException
      Signal that an element has been found that matches the selection that this Watch is looking for. This method is called by the ConstraintChecker while processing the startElement event that matches the selection. For this purpose, any attributes selected by the last step in the selection are ignored
      Parameters:
      node - the element or document node whose start event has been matched
      locationId - the location associated with the element or document node (may be the location of the instruction that created it)
      Returns:
      a FieldChecker - a receiver that collects the contents of the selected node, or null
      Throws:
      ValidationException - May be raised if the constraint implemented by this Watch is violated @param locationId the location of the node in the source, or of the instruction that created it
      XPathException - May be raised if a dynamic error occurs
    • endSelectedParentNode

      public void endSelectedParentNode(Location locationId) throws ValidationException
      Signal that the endElement event has occurred for the element whose startElement event caused the Watch to be activated.
      Parameters:
      locationId - the location of the node in the source, or of the instruction that created it
      Throws:
      ValidationException - May be raised if the constraint implemented by this Watch is violated @param locationId the location of the node in the source, or of the instruction that created it
    • processItem

      public void processItem(Item item) throws XPathException
      Signal that a node (other than an element) that matches the selection has been found.
      Specified by:
      processItem in interface Watch
      Overrides:
      processItem in class PatternWatch
      Parameters:
      item - the node that was matched.
      Throws:
      XPathException - May be raised if a dynamic error occurs