net.sf.saxon.pull
Class PullFilter

java.lang.Object
  net.sf.saxon.pull.PullFilter

All Implemented Interfaces:

PullProvider

Direct Known Subclasses:

DocumentEventIgnorer, ElementNameTracker, PullNamespaceReducer, PullPushTee, PullTracer

public class PullFilter
extends Object
implements PullProvider

PullFilter is a pass-through filter class that links one PullProvider to another PullProvider in a pipeline. This class passes all events through completely unchanged. The class is designed so that subclasses can modify this behavior by altering some of the events.

Field Summary

protected int

currentEvent

Fields inherited from interface net.sf.saxon.pull.PullProvider

ATOMIC_VALUE, ATTRIBUTE, COMMENT, END_DOCUMENT, END_ELEMENT, END_OF_INPUT, NAMESPACE, PROCESSING_INSTRUCTION, START_DOCUMENT, START_ELEMENT, START_OF_INPUT, TEXT

Constructor Summary

PullFilter(PullProvider base)
Create a PullFilter

Method Summary

void	close() Close the event reader.
int	current() Get the event most recently returned by next(), or by other calls that change the position, for example getStringValue() and skipToMatchingEnd().
AtomicValue	getAtomicValue() Get an atomic value.
AttributeCollection	getAttributes() Get the attributes associated with the current element.
int	getFingerprint() Get the fingerprint of the name of the element.
int	getNameCode() Get the nameCode identifying the name of the current node.
NamePool	getNamePool() Helper method to get the current namePool
NamespaceBinding[]	getNamespaceDeclarations() Get the namespace declarations associated with the current element.
PipelineConfiguration	getPipelineConfiguration() Get configuration information.
SchemaType	getSchemaType() Get the type annotation of the current attribute or element node, or atomic value.
SourceLocator	getSourceLocator() Get the location of the current event.
CharSequence	getStringValue() Get the string value of the current element, text node, processing-instruction, or top-level attribute or namespace node, or atomic value.
PullProvider	getUnderlyingProvider() Get the underlying PullProvider
List	getUnparsedEntities() Get a list of unparsed entities.
int	next() Get the next event.
void	setPipelineConfiguration(PipelineConfiguration pipe) Set configuration information.
int	skipToMatchingEnd() Skip the current subtree.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

currentEvent

protected int currentEvent

Constructor Detail

PullFilter

public PullFilter(PullProvider base)

Create a PullFilter

Parameters:

base - the PullProvider to which requests are to be passed

Method Detail

setPipelineConfiguration

public void setPipelineConfiguration(PipelineConfiguration pipe)

Set configuration information. This must only be called before any events have been read.

Specified by:

setPipelineConfiguration in interface PullProvider

Parameters:

pipe - the pipeline configuration

getPipelineConfiguration

public PipelineConfiguration getPipelineConfiguration()

Get configuration information.

Specified by:

getPipelineConfiguration in interface PullProvider

Returns:

the pipeline configuration

getNamePool

public final NamePool getNamePool()

Helper method to get the current namePool

Returns:

the NamePool

getUnderlyingProvider

public PullProvider getUnderlyingProvider()

Get the underlying PullProvider

Returns:

the underlying PullProvider

next

public int next()
         throws XPathException

Get the next event.

Note that a subclass that overrides this method is responsible for ensuring that current() works properly. This can be achieved by setting the field currentEvent to the event returned by any call on next().

Specified by:

next in interface PullProvider

Returns:

an integer code indicating the type of event. The code PullProvider.END_OF_INPUT is returned at the end of the sequence.

Throws:

XPathException - if a dynamic error occurs

current

public int current()

Get the event most recently returned by next(), or by other calls that change the position, for example getStringValue() and skipToMatchingEnd(). This method does not change the position of the PullProvider.

Specified by:

current in interface PullProvider

Returns:

the current event

getAttributes

public AttributeCollection getAttributes()
                                  throws XPathException

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

Returns:

an AttributeCollection representing the attributes of the element that has just been notified.

Throws:

XPathException - if a dynamic error occurs

getNamespaceDeclarations

public NamespaceBinding[] getNamespaceDeclarations()
                                            throws XPathException

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.

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

Returns:

the namespace declarations associated with the current START_ELEMENT event.

Throws:

XPathException - if a dynamic error occurs

skipToMatchingEnd

public int skipToMatchingEnd()
                      throws XPathException

Skip the current subtree. This method may be called only immediately after a START_DOCUMENT or START_ELEMENT event. This call returns the matching END_DOCUMENT or END_ELEMENT event; the next call on next() will return the event following the END_DOCUMENT or END_ELEMENT.

Specified by:

skipToMatchingEnd in interface PullProvider

Returns:

the matching END_DOCUMENT or END_ELEMENT event

Throws:

XPathException - if a dynamic error occurs

close

public void close()

Close the event reader. This indicates that no further events are required. It is not necessary to close an event reader after PullProvider.END_OF_INPUT has been reported, but it is recommended to close it if reading terminates prematurely. Once an event reader has been closed, the effect of further calls on next() is undefined.

Specified by:

close in interface PullProvider

getNameCode

public int getNameCode()

Get the nameCode identifying the name of the current node. This method can be used after the PullProvider.START_ELEMENT, PullProvider.PROCESSING_INSTRUCTION, PullProvider.ATTRIBUTE, or PullProvider.NAMESPACE events. With some PullProvider implementations, it can also be used after PullProvider.END_ELEMENT, but this is not guaranteed: a client who requires the information at that point (for example, to do serialization) should insert an ElementNameTracker into the pipeline. If called at other times, the result is undefined and may result in an IllegalStateException. If called when the current node is an unnamed namespace node (a node representing the default namespace) the returned value is -1.

Specified by:

getNameCode in interface PullProvider

Returns:

the nameCode. The nameCode can be used to obtain the prefix, local name, and namespace URI from the name pool.

getFingerprint

public int getFingerprint()

Get the fingerprint of the name of the element. This is similar to the nameCode, except that it does not contain any information about the prefix: so two elements with the same fingerprint have the same name, excluding prefix. This method can be used after the PullProvider.START_ELEMENT, PullProvider.END_ELEMENT, PullProvider.PROCESSING_INSTRUCTION, PullProvider.ATTRIBUTE, or PullProvider.NAMESPACE events. If called at other times, the result is undefined and may result in an IllegalStateException. If called when the current node is an unnamed namespace node (a node representing the default namespace) the returned value is -1.

Specified by:

getFingerprint in interface PullProvider

Returns:

the fingerprint. The fingerprint can be used to obtain the local name and namespace URI from the name pool.

getStringValue

public CharSequence getStringValue()
                            throws XPathException

Get the string value of the current element, text node, processing-instruction, or top-level attribute or namespace node, or atomic value.

In other situations the result is undefined and may result in an IllegalStateException.

If the most recent event was a PullProvider.START_ELEMENT, this method causes the content of the element to be read. The next event notified will be the corresponding PullProvider.END_ELEMENT.

Specified by:

getStringValue in interface PullProvider

Returns:

the String Value of the node in question, defined according to the rules in the XPath data model.

Throws:

XPathException - if a dynamic error occurs

getAtomicValue

public AtomicValue getAtomicValue()

Get an atomic value. This call may be used only when the last event reported was ATOMIC_VALUE. This indicates that the PullProvider is reading a sequence that contains a free-standing atomic value; it is never used when reading the content of a node.

Specified by:

getAtomicValue in interface PullProvider

Returns:

the atomic value

getSchemaType

public SchemaType getSchemaType()

Get the type annotation of the current attribute or element node, or atomic value. The result of this method is undefined unless the most recent event was START_ELEMENT, ATTRIBUTE, or ATOMIC_VALUE.

Specified by:

getSchemaType in interface PullProvider

Returns:

the type annotation.

getSourceLocator

public SourceLocator getSourceLocator()

Get the location of the current event. For an event stream representing a real document, the location information should identify the location in the lexical XML source. For a constructed document, it should identify the location in the query or stylesheet that caused the node to be created. A value of null can be returned if no location information is available.

Specified by:

getSourceLocator in interface PullProvider

Returns:

the SourceLocator giving the location of the current event, or null if no location information is available

getUnparsedEntities

public List getUnparsedEntities()

Get a list of unparsed entities.

Specified by:

getUnparsedEntities in interface PullProvider

Returns:

a list of unparsed entities, or null if the information is not available, or an empty list if there are no unparsed entities.