Package com.saxonica.ee.stream.watch

Class WatchManager

  • All Implemented Interfaces:
    javax.xml.transform.Result, Receiver, NamespaceResolver
    Direct Known Subclasses:
    ConstraintChecker
    public class WatchManager
extends SequenceReceiver
implements NamespaceResolver
    This class sits on a push pipeline and evaluates the passing element and attribute nodes. One or more Watch objects can be registered with the pipeline at any time; element and attribute events are notified to the active Watch objects. A watch that is added immediately after a startElement call is automatically dropped at the corresponding endElement call. If a Watch matches a startElement call, then it becomes an active Watch; it is automatically deactivated (but not dropped) at the corresponding endElement call.

    A Watch is not itself a receiver, but it can nominate a Receiver to receive all events while it is active. It will stop receiving events when it is deactivated.

    • Field Detail

      • elementStackTop

        protected int elementStackTop

      • watchList

        protected java.util.List<Watch> watchList

      • activeWatchStack

        protected java.util.Stack<java.util.List<com.saxonica.ee.stream.watch.WatchManager.ClosedownAction>> activeWatchStack

    • Constructor Detail

      • WatchManager

        public WatchManager​(PipelineConfiguration pipe)
        Create a WatchManager
        Parameters:
        pipe - the pipeline configuration

    • Method Detail

      • setXPathContext

        public void setXPathContext​(XPathContext context)

      • setOutputter

        public void setOutputter​(Outputter outputter)

      • getOutputter

        public Outputter getOutputter()

      • append

        public void append​(Item item,
                   Location locationId,
                   int copyNamespaces)
            throws XPathException
        Append an arbitrary item (node or atomic value) to the output
        Specified by:
        append in interface Receiver
        Specified by:
        append in class SequenceReceiver
        Parameters:
        item - the item to be appended
        locationId - the location of the calling instruction, for diagnostics
        copyNamespaces - if the item is an element node, this indicates whether its namespaces need to be copied. Values are ReceiverOption.ALL_NAMESPACES; the default (0) means
        Throws:
        XPathException - if an error occurs

      • startElement

        public void startElement​(NodeName elementName,
                         SchemaType typeCode,
                         AttributeMap attributes,
                         NamespaceMap namespaces,
                         Location location,
                         int properties)
                  throws XPathException
        Output element start tag
        Specified by:
        startElement in interface Receiver
        Parameters:
        elementName - the name of the element.
        typeCode - the type annotation of the element.
        attributes - the attributes of this element
        namespaces - the in-scope namespaces of this element: generally this is all the in-scope namespaces, without relying on inheriting namespaces from parent elements
        location - an object providing information about the module, line, and column where the node originated
        properties - bit-significant properties of the element node. If there are no relevant properties, zero is supplied. The definitions of the bits are in class ReceiverOption
        Throws:
        XPathException - if an error occurs

      • restartElement

        public void restartElement​(Watch watch)
                    throws XPathException
        During schema validation, the startElement() event is emitted before we can examine all the streamed assertions that might apply to that element. So this method can be used to process a Watch against the most recent start element event, on the basis that we might have missed it the first time round.
        Throws:
        XPathException

      • getDepth

        public int getDepth()

      • characters

        public void characters​(java.lang.CharSequence chars,
                       Location locationId,
                       int properties)
                throws XPathException
        Text node
        Specified by:
        characters in interface Receiver
        Parameters:
        chars - The characters
        locationId - provides information such as line number and system ID.
        properties - Bit significant value. The following bits are defined:
        DISABLE_ESCAPING
        Disable escaping for this text node
        USE_CDATA
        Output as a CDATA section
        Throws:
        XPathException - if an error occurs

      • comment

        public void comment​(java.lang.CharSequence chars,
                    Location locationId,
                    int properties)
             throws XPathException
        Output a comment
        Specified by:
        comment in interface Receiver
        Parameters:
        chars - The content of the comment
        locationId - provides information such as line number and system ID.
        properties - Additional information about the comment.
        Throws:
        XPathException - if an error occurs

      • processingInstruction

        public void processingInstruction​(java.lang.String target,
                                  java.lang.CharSequence data,
                                  Location locationId,
                                  int properties)
                           throws XPathException
        Processing Instruction
        Specified by:
        processingInstruction in interface Receiver
        Parameters:
        target - The PI name. This must be a legal name (it will not be checked).
        data - The data portion of the processing instruction
        locationId - provides information such as line number and system ID.
        properties - Additional information about the PI.
        Throws:
        XPathException - if an error occurs

      • setUnparsedEntity

        public void setUnparsedEntity​(java.lang.String name,
                              java.lang.String systemID,
                              java.lang.String publicID)
                       throws XPathException
        Notify an unparsed entity URI.
        Specified by:
        setUnparsedEntity in interface Receiver
        Overrides:
        setUnparsedEntity in class SequenceReceiver
        Parameters:
        name - The name of the unparsed entity
        systemID - The system identifier of the unparsed entity
        publicID - The public identifier of the unparsed entity
        Throws:
        XPathException - if an error occurs

      • addWatch

        public void addWatch​(Watch watch,
                     boolean autoClose)
              throws XPathException
        Add a new Watch. This is associated with the current level in the element stack, and is automatically closed and dropped when the current element goes out of scope.
        Parameters:
        watch - the watch to be added
        autoClose - set to true if the watch is to be automatically opened as soon as it is registered, and is to be automatically closed when it goes out of scope.
        Throws:
        XPathException - if any error occurs

      • removeWatch

        public void removeWatch​(Watch watch)
        Remove a watch
        Parameters:
        watch - the watch to be removed. No error occurs if the watch is unknown or inactive.

      • getURIForPrefix

        public java.lang.String getURIForPrefix​(java.lang.String prefix,
                                        boolean useDefault)
        Get the namespace URI corresponding to a given prefix. Return null if the prefix is not in scope.
        Specified by:
        getURIForPrefix in interface NamespaceResolver
        Parameters:
        prefix - the namespace prefix. May be the zero-length string, indicating that there is no prefix. This indicates either the default namespace or the null namespace, depending on the value of useDefault.
        useDefault - true if the default namespace is to be used when the prefix is "". If false, the method returns "" when the prefix is "".
        Returns:
        the uri for the namespace, or null if the prefix is not in scope. The "null namespace" is represented by the pseudo-URI "".

      • iteratePrefixes

        public java.util.Iterator<java.lang.String> iteratePrefixes()
        Description copied from interface: NamespaceResolver
        Get an iterator over all the prefixes declared in this namespace context. This will include the default namespace (prefix="") and the XML namespace where appropriate
        Specified by:
        iteratePrefixes in interface NamespaceResolver
        Returns:
        an iterator over all the prefixes for which a namespace binding exists, including the zero-length string to represent the null/absent prefix if it is bound

      • usesTypeAnnotations

        public boolean usesTypeAnnotations()
        Ask whether this Receiver (or the downstream pipeline) makes any use of the type annotations supplied on element and attribute events
        Specified by:
        usesTypeAnnotations in interface Receiver
        Returns:
        true if the Receiver makes any use of this information. If false, the caller may supply untyped nodes instead of supplying the type annotation

      • startGroupingScope

        public WatchManager.GroupingScope startGroupingScope()
        Called during a partitioning for-each-group whenever a new group is started