Class SignificantItemDetector

  • All Implemented Interfaces:
    javax.xml.transform.Result, Receiver

    public class SignificantItemDetector
    extends ProxyOutputter
    This receiver is inserted into the output pipeline whenever on-empty or on-non-empty is used (XSLT 3.0). It passes all events to the underlying receiver unchanged, but invokes a callback action when the first item is written.

    A "Significant Item" as detected by this class is an item that is not "vacuous" according to section 8.4.2 of the XSLT 3.0 specification. Note that this is not the same as being "deemed empty" as defined in section 8.4.1: notably, empty elements and empty maps are "deemed empty" but are not "vacuous".

    • Constructor Detail

      • SignificantItemDetector

        public SignificantItemDetector​(Outputter next,
                                       Action trigger)
    • Method Detail

      • startElement

        public void startElement​(NodeName elemName,
                                 SchemaType type,
                                 Location location,
                                 int properties)
                          throws XPathException
        Description copied from class: ProxyOutputter
        Notify the start of an element
        Overrides:
        startElement in class ProxyOutputter
        Parameters:
        elemName - the name of the element.
        type - the type annotation of the element.
        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
      • startElement

        public void startElement​(NodeName elemName,
                                 SchemaType type,
                                 AttributeMap attributes,
                                 NamespaceMap namespaces,
                                 Location location,
                                 int properties)
                          throws XPathException
        Notify the start of an element, supplying all attributes and namespaces
        Specified by:
        startElement in interface Receiver
        Overrides:
        startElement in class ProxyOutputter
        Parameters:
        elemName - the name of the element.
        type - 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
      • namespace

        public void namespace​(java.lang.String prefix,
                              NamespaceUri namespaceUri,
                              int properties)
                       throws XPathException
        Notify a namespace binding.
        Overrides:
        namespace in class ProxyOutputter
        Parameters:
        prefix - The namespace prefix; zero-length string for the default namespace
        namespaceUri - The namespace URI. In some cases a zero-length string may be used to indicate a namespace undeclaration.
        properties - The REJECT_DUPLICATES property: if set, the namespace declaration will be rejected if it conflicts with a previous declaration of the same prefix. If the property is not set, the namespace declaration will be ignored if it conflicts with a previous declaration. This reflects the fact that when copying a tree, namespaces for child elements are emitted before the namespaces of their parent element. Unfortunately this conflicts with the XSLT rule for complex content construction, where the recovery action in the event of conflicts is to take the namespace that comes last. XSLT therefore doesn't recover from this error:
        Throws:
        XPathException - if an error occurs
      • attribute

        public void attribute​(NodeName attName,
                              SimpleType typeCode,
                              java.lang.String value,
                              Location location,
                              int properties)
                       throws XPathException
        Notify an attribute.
        Overrides:
        attribute in class ProxyOutputter
        Parameters:
        attName - The name of the attribute
        typeCode - The type annotation of the attribute
        value - the string value of the attribute
        location - provides information such as line number and system ID.
        properties - Bit significant value. The following bits are defined:
        DISABLE_ESCAPING
        Disable escaping for this attribute
        NO_SPECIAL_CHARACTERS
        Attribute value contains no special characters
        Throws:
        XPathException - if an error occurs
      • characters

        public void characters​(UnicodeString chars,
                               Location locationId,
                               int properties)
                        throws XPathException
        Description copied from class: ProxyOutputter
        Notify character data. Note that some receivers may require the character data to be sent in a single event, but in general this is not a requirement.
        Specified by:
        characters in interface Receiver
        Overrides:
        characters in class ProxyOutputter
        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
      • processingInstruction

        public void processingInstruction​(java.lang.String target,
                                          UnicodeString data,
                                          Location locationId,
                                          int properties)
                                   throws XPathException
        Description copied from class: ProxyOutputter
        Output a processing instruction
        Specified by:
        processingInstruction in interface Receiver
        Overrides:
        processingInstruction in class ProxyOutputter
        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
      • comment

        public void comment​(UnicodeString chars,
                            Location locationId,
                            int properties)
                     throws XPathException
        Description copied from class: ProxyOutputter
        Notify a comment. Comments are only notified if they are outside the DTD.
        Specified by:
        comment in interface Receiver
        Overrides:
        comment in class ProxyOutputter
        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
      • isSignificant

        public static boolean isSignificant​(Item item)
      • append

        public void append​(Item item,
                           Location locationId,
                           int copyNamespaces)
                    throws XPathException
        Description copied from class: ProxyOutputter
        Append an arbitrary item (node, atomic value, or function) to the output. The default implementation throws UnsupportedOperationException.
        Specified by:
        append in interface Receiver
        Overrides:
        append in class ProxyOutputter
        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
      • isEmpty

        public boolean isEmpty()
        Ask if the sequence that has been written so far is considered empty
        Returns:
        true if no significant items have been written (or started)