Package com.saxonica.xqj.pull

Class PullNamespaceReducer

  • All Implemented Interfaces:
    NamespaceResolver, PullProvider
    public class PullNamespaceReducer
extends PullFilter
implements NamespaceResolver
    PullNamespaceReducer is a PullFilter responsible for removing duplicate namespace declarations. It also performs namespace fixup: that is, it ensures that the namespaces used in element and attribute names are all declared.

    This class is derived from, and contains much common code with, the NamespaceReducer in the push pipeline. (In the push version, however, namespace fixup is not performed by the NamespaceReducer, but by the ComplexContentOutputter).

    See Also:
    NamespaceReducer

    • Constructor Detail

      • PullNamespaceReducer

        public PullNamespaceReducer​(PullProvider base)
        Create a namespace reducer for a pull pipeline
        Parameters:
        base - the next stage in the pipeline, from which events are read

    • Method Detail

      • next

        public PullEvent next()
               throws XPathException
        next(): handle next event. The START_ELEMENT event removes redundant namespace declarations, and possibly adds an xmlns="" undeclaration.
        Specified by:
        next in interface PullProvider
        Overrides:
        next in class PullFilter
        Returns:
        an integer code indicating the type of event. The code PullEvent.END_OF_INPUT is returned at the end of the sequence.
        Throws:
        XPathException - if a dynamic error occurs

      • getAttributes

        public AttributeMap getAttributes()
        Get the attributes associated with the current element. This method must be called only after a START_ELEMENT event has been notified. The contents of the returned AttributeCollection are guaranteed to remain unchanged until the next START_ELEMENT event, but may be modified thereafter. The object should not be modified by the client.

        Attributes may be read before or after reading the namespaces of an element, but must not be read after the first child node has been read, or after calling one of the methods skipToEnd(), getStringValue(), or getTypedValue().

        Specified by:
        getAttributes in interface PullProvider
        Overrides:
        getAttributes in class PullFilter
        Returns:
        an AttributeCollection representing the attributes of the element that has just been notified.

      • getNamespaceDeclarations

        public NamespaceBinding[] getNamespaceDeclarations()
        Get the namespace declarations associated with the current element. This method must be called only after a START_ELEMENT event has been notified. In the case of a top-level START_ELEMENT event (that is, an element that either has no parent node, or whose parent is not included in the sequence being read), the NamespaceDeclarations object returned will contain a namespace declaration for each namespace that is in-scope for this element node. In the case of a non-top-level element, the NamespaceDeclarations will contain a set of namespace declarations and undeclarations, representing the differences between this element and its parent.

        This class extends the semantics of the PullProvider interface by allowing this method to be called also after an END_ELEMENT event. This is to support PullToStax, which requires this functionality. In this situation it returns the namespaces declared on the startElement associated with the element that has just ended.

        It is permissible for this method to return namespace declarations that are redundant.

        The NamespaceDeclarations object is guaranteed to remain unchanged until the next START_ELEMENT event, but may then be overwritten. The object should not be modified by the client.

        Namespaces may be read before or after reading the attributes of an element, but must not be read after the first child node has been read, or after calling one of the methods skipToEnd(), getStringValue(), or getTypedValue().

        Specified by:
        getNamespaceDeclarations in interface PullProvider
        Overrides:
        getNamespaceDeclarations in class PullFilter
        Returns:
        the namespace declarations associated with the current START_ELEMENT event.

      • endElement

        public void endElement()
                throws XPathException
        endElement: Discard the namespaces declared on this element. Note, however, that for the benefit of PullToStax, the namespaces that go out of scope on this endElement are available so long as the endElement is the current event
        Throws:
        XPathException

      • getURIForPrefix

        public NamespaceUri 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
        useDefault - true if the default namespace is to be used when the prefix is ""
        Returns:
        the uri for the namespace, or null if the prefix is not in scope

      • iteratePrefixes

        public java.util.Iterator<java.lang.String> iteratePrefixes()
        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