net.sf.saxon.style
Class UseWhenFilter

java.lang.Object
  net.sf.saxon.event.SequenceReceiver
      net.sf.saxon.event.ProxyReceiver
          net.sf.saxon.style.UseWhenFilter

All Implemented Interfaces:

Result, Receiver

public class UseWhenFilter
extends ProxyReceiver

This is a filter inserted into the input pipeline for processing stylesheet modules, whose task is to evaluate use-when expressions and discard those parts of the stylesheet module for which the use-when attribute evaluates to false.

Field Summary

Fields inherited from class net.sf.saxon.event.ProxyReceiver

nextReceiver

Fields inherited from class net.sf.saxon.event.SequenceReceiver

pipelineConfiguration, previousAtomic, systemId

Fields inherited from interface javax.xml.transform.Result

PI_DISABLE_OUTPUT_ESCAPING, PI_ENABLE_OUTPUT_ESCAPING

Constructor Summary

UseWhenFilter(StartTagBuffer startTag)
Create a UseWhenFilter

Method Summary

void	attribute(int nameCode, int typeCode, CharSequence value, int locationId, int properties) Notify an attribute.
void	characters(CharSequence chars, int locationId, int properties) Character data
void	comment(CharSequence chars, int locationId, int properties) Output a comment
void	endElement() End of element
boolean	evaluateUseWhen(String expression, int locationId) Evaluate a use-when attribute
void	namespace(int namespaceCode, int properties) Notify a namespace.
void	open() Start of document
void	processingInstruction(String target, CharSequence data, int locationId, int properties) Processing Instruction
void	startContent() Notify the start of the content, that is, the completion of all attributes and namespaces.
void	startElement(int nameCode, int typeCode, int locationId, int properties) Notify the start of an element.

Methods inherited from class net.sf.saxon.event.ProxyReceiver

append, close, endDocument, getConfiguration, getDocumentLocator, getNamePool, getUnderlyingReceiver, setPipelineConfiguration, setSystemId, setUnderlyingReceiver, setUnparsedEntity, startDocument, usesTypeAnnotations

Methods inherited from class net.sf.saxon.event.SequenceReceiver

getPipelineConfiguration, getSystemId

Methods inherited from class java.lang.Object

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

Constructor Detail

UseWhenFilter

public UseWhenFilter(StartTagBuffer startTag)

Create a UseWhenFilter

Parameters:

startTag - a preceding filter on the pipeline that buffers the attributes of a start tag

Method Detail

open

public void open()
          throws XPathException

Start of document

Specified by:

open in interface Receiver

Overrides:

open in class ProxyReceiver

Throws:

XPathException

startElement

public void startElement(int nameCode,
                         int typeCode,
                         int locationId,
                         int properties)
                  throws XPathException

Notify the start of an element.

Specified by:

startElement in interface Receiver

Overrides:

startElement in class ProxyReceiver

Parameters:

nameCode - integer code identifying the name of the element within the name pool.

typeCode - integer code identifying the element's type within the name pool.

properties - bit-significant properties of the element node

locationId - an integer which can be interpreted using a LocationProvider to return information such as line number and system ID. If no location information is available, the value zero is supplied.

Throws:

XPathException

namespace

public void namespace(int namespaceCode,
                      int properties)
               throws XPathException

Notify a namespace. Namespaces are notified after the startElement event, and before any children for the element. The namespaces that are reported are only required to include those that are different from the parent element; however, duplicates may be reported. A namespace must not conflict with any namespaces already used for element or attribute names.

Specified by:

namespace in interface Receiver

Overrides:

namespace in class ProxyReceiver

Parameters:

namespaceCode - an integer: the top half is a prefix code, the bottom half a URI code. These may be translated into an actual prefix and URI using the name pool. A prefix code of zero represents the empty prefix (that is, the default namespace). A URI code of zero represents a URI of "", that is, a namespace undeclaration.

properties - The most important property is REJECT_DUPLICATES. If this property is 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: it sets the REJECT_DUPLICATES flag, and this is treated as a hard error.

Throws:

IllegalStateException: - attempt to output a namespace when there is no open element start tag

XPathException

attribute

public void attribute(int nameCode,
                      int typeCode,
                      CharSequence value,
                      int locationId,
                      int properties)
               throws XPathException

Notify an attribute. Attributes are notified after the startElement event, and before any children. Namespaces and attributes may be intermingled.

Specified by:

attribute in interface Receiver

Overrides:

attribute in class ProxyReceiver

Parameters:

nameCode - The name of the attribute, as held in the name pool

typeCode - The type of the attribute, as held in the name pool

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

value - the string value of the attribute

locationId - an integer which can be interpreted using a LocationProvider to return information such as line number and system ID. If no location information is available, the value zero is supplied.

Throws:

IllegalStateException: - attempt to output an attribute when there is no open element start tag

XPathException

startContent

public void startContent()
                  throws XPathException

Notify the start of the content, that is, the completion of all attributes and namespaces. Note that the initial receiver of output from XSLT instructions will not receive this event, it has to detect it itself. Note that this event is reported for every element even if it has no attributes, no namespaces, and no content.

Specified by:

startContent in interface Receiver

Overrides:

startContent in class ProxyReceiver

Throws:

XPathException

endElement

public void endElement()
                throws XPathException

End of element

Specified by:

endElement in interface Receiver

Overrides:

endElement in class ProxyReceiver

Throws:

XPathException

characters

public void characters(CharSequence chars,
                       int locationId,
                       int properties)
                throws XPathException

Character data

Specified by:

characters in interface Receiver

Overrides:

characters in class ProxyReceiver

Parameters:

chars - The characters

locationId - an integer which can be interpreted using a LocationProvider to return information such as line number and system ID. If no location information is available, the value zero is supplied.

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

processingInstruction

public void processingInstruction(String target,
                                  CharSequence data,
                                  int locationId,
                                  int properties)

Processing Instruction

Specified by:

processingInstruction in interface Receiver

Overrides:

processingInstruction in class ProxyReceiver

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 - an integer which can be interpreted using a LocationProvider to return information such as line number and system ID. If no location information is available, the value zero is supplied.

properties - Additional information about the PI. The following bits are defined:

CHECKED

Data is known to be legal (e.g. doesn't contain "?>")

comment

public void comment(CharSequence chars,
                    int locationId,
                    int properties)
             throws XPathException

Output a comment

Specified by:

comment in interface Receiver

Overrides:

comment in class ProxyReceiver

Parameters:

chars - The content of the comment

locationId - an integer which can be interpreted using a LocationProvider to return information such as line number and system ID. If no location information is available, the value zero is supplied.

properties - Additional information about the comment. The following bits are defined:

CHECKED

Comment is known to be legal (e.g. doesn't contain "--")

Throws:

XPathException

evaluateUseWhen

public boolean evaluateUseWhen(String expression,
                               int locationId)
                        throws XPathException

Evaluate a use-when attribute

Parameters:

expression - the expression to be evaluated

locationId - identifies the location of the expression in case error need to be reported

Returns:

the effective boolean value of the result of evaluating the expression

Throws:

XPathException