Package net.sf.saxon.event

Class SignificantItemDetector

java.lang.Object

net.sf.saxon.event.Outputter

net.sf.saxon.event.ProxyOutputter

net.sf.saxon.event.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".

Field Summary

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

pipelineConfiguration, systemId

Fields inherited from interface javax.xml.transform.Result

PI_DISABLE_OUTPUT_ESCAPING, PI_ENABLE_OUTPUT_ESCAPING

Constructor Summary

Constructors

Constructor	Description
SignificantItemDetector(Outputter next, Action trigger)

Method Summary

Modifier and Type	Method	Description
void	append(Item item)	Append an arbitrary item (node, atomic value, or function) to the output.
void	append(Item item, Location locationId, int copyNamespaces)	Append an arbitrary item (node, atomic value, or function) to the output.
void	attribute(NodeName attName, SimpleType typeCode, java.lang.String value, Location location, int properties)	Notify an attribute.
void	characters(UnicodeString chars, Location locationId, int properties)	Notify character data.
void	comment(UnicodeString chars, Location locationId, int properties)	Notify a comment.
void	endDocument()	Notify the end of a document node
void	endElement()	End of element
boolean	isEmpty()	Ask if the sequence that has been written so far is considered empty
static boolean	isSignificant(Item item)
void	namespace(java.lang.String prefix, NamespaceUri namespaceUri, int properties)	Notify a namespace binding.
void	processingInstruction(java.lang.String target, UnicodeString data, Location locationId, int properties)	Output a processing instruction
void	startContent()	Notify the start of the content, that is, the completion of all attributes and namespaces.
void	startDocument(int properties)	Start of a document node.
void	startElement(NodeName elemName, SchemaType type, AttributeMap attributes, NamespaceMap namespaces, Location location, int properties)	Notify the start of an element, supplying all attributes and namespaces
void	startElement(NodeName elemName, SchemaType type, Location location, int properties)	Notify the start of an element

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

close, getNextOutputter, open, setUnparsedEntity, usesTypeAnnotations

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

getConfiguration, getPipelineConfiguration, getStringReceiver, getSystemId, namespaces, setPipelineConfiguration, setSystemId

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.event.Receiver

handlesAppend

Constructor Detail

SignificantItemDetector

public SignificantItemDetector(Outputter next,
                               Action trigger)

Method Detail

startDocument

public void startDocument(int properties)
                   throws XPathException

Start of a document node.

Specified by:

startDocument in interface Receiver

Overrides:

startDocument in class ProxyOutputter

Parameters:

properties - bit-significant integer indicating properties of the document node. The definitions of the bits are in class ReceiverOption

Throws:

XPathException - if an error occurs

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

startContent

public void startContent()
                  throws XPathException

Notify the start of the content, that is, the completion of all attributes and namespaces.

Overrides:

startContent in class ProxyOutputter

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

append

public void append(Item item)
            throws XPathException

Description copied from class: ProxyOutputter

Append an arbitrary item (node, atomic value, or function) to the output. By default, if the item is an element node, it is copied with all namespaces. The default implementation calls ProxyOutputter.append(Item, Location, int), whose default implementation throws UnsupportedOperationException

Specified by:

append in interface Receiver

Overrides:

append in class ProxyOutputter

Parameters:

item - the item to be appended

Throws:

XPathException - if the operation fails

endDocument

public void endDocument()
                 throws XPathException

Notify the end of a document node

Specified by:

endDocument in interface Receiver

Overrides:

endDocument in class ProxyOutputter

Throws:

XPathException - if an error occurs

endElement

public void endElement()
                throws XPathException

End of element

Specified by:

endElement in interface Receiver

Overrides:

endElement in class ProxyOutputter

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)