net.sf.saxon.style
Class UseWhenFilter

java.lang.Object
  extended by net.sf.saxon.event.SequenceReceiver
      extended by net.sf.saxon.event.ProxyReceiver
          extended by 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 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
 
Methods inherited from class net.sf.saxon.event.SequenceReceiver
getPipelineConfiguration, getSystemId
 
Methods inherited from class java.lang.Object
equals, 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


Copyright (C) Michael H. Kay. All rights reserved.