com.saxonica.stream
Class WatchManager

java.lang.Object
  extended by net.sf.saxon.event.SequenceReceiver
      extended by net.sf.saxon.event.ProxyReceiver
          extended by com.saxonica.stream.WatchManager
All Implemented Interfaces:
Result, Receiver, NamespaceResolver
Direct Known Subclasses:
ConstraintChecker

public class WatchManager
extends ProxyReceiver
implements NamespaceResolver

This class sits on a push pipeline and evaluates the passing element and attribute nodes. One or more Watch objects can be registered with the pipeline at any time; element and attribute events are notified to the active Watch objects. A watch that is added immediately after a startElement call is automatically dropped at the corresponding endElement call. If a Watch matches a startElement call, then it becomes an active Watch; it is automatically deactivated (but not dropped) at the corresponding endElement call.

A Watch is not itself a receiver, but it can nominate a Receiver to receive all events while it is active. It will stop receiving events when it is deactivated.


Field Summary
protected  Stack activeWatchStack
           
protected  int elementStackTop
           
static List EMPTY_WATCH_LIST
           
protected  List watchList
           
 
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
WatchManager()
          Create a WatchManager
 
Method Summary
 void addWatch(Watch watch)
          Add a new Watch.
 void attribute(int nameCode, int typeCode, CharSequence value, int locationId, int properties)
          Notify an attribute
 void characters(CharSequence chars, int locationId, int properties)
          Text node
 void comment(CharSequence chars, int locationId, int properties)
          Output a comment
 void endElement()
          Notify end of element
 String getURIForPrefix(String prefix, boolean useDefault)
          Get the namespace URI corresponding to a given prefix.
 Iterator iteratePrefixes()
          Get an iterator over all the prefixes declared in this namespace context.
 void namespace(int namespaceCode, int properties)
          Notify a namespace
 void processingInstruction(String target, CharSequence data, int locationId, int properties)
          Processing Instruction
 void startContent()
          Start element content (called after all the attributes and namespaces have been processed)
 void startElement(int nameCode, int typeCode, int locationId, int properties)
          Output element start tag
 boolean usesTypeAnnotations()
          Ask whether this Receiver (or the downstream pipeline) makes any use of the type annotations supplied on element and attribute events
 
Methods inherited from class net.sf.saxon.event.ProxyReceiver
append, close, endDocument, getConfiguration, getDocumentLocator, getNamePool, getUnderlyingReceiver, open, setPipelineConfiguration, setSystemId, setUnderlyingReceiver, setUnparsedEntity, startDocument
 
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
 

Field Detail

elementStackTop

protected int elementStackTop

watchList

protected List watchList

activeWatchStack

protected Stack activeWatchStack

EMPTY_WATCH_LIST

public static final List EMPTY_WATCH_LIST
Constructor Detail

WatchManager

public WatchManager()
Create a WatchManager

Method Detail

startElement

public void startElement(int nameCode,
                         int typeCode,
                         int locationId,
                         int properties)
                  throws XPathException
Output element start tag

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.
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 - properties of the element node
Throws:
XPathException

attribute

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

Specified by:
attribute in interface Receiver
Overrides:
attribute in class ProxyReceiver
Parameters:
nameCode - integer identifying the name of the attribute
typeCode - integer identifying the type annotation (ignored)
value - the value of the attribute
properties - additional properties 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:
XPathException - On any failure to write the attribute

namespace

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

Specified by:
namespace in interface Receiver
Overrides:
namespace in class ProxyReceiver
Parameters:
namespaceCode - the namespace code (identifies the prefix and URI)
properties - properties of this event
Throws:
XPathException

characters

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

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

endElement

public void endElement()
                throws XPathException
Notify end of element

Specified by:
endElement in interface Receiver
Overrides:
endElement in class ProxyReceiver
Throws:
XPathException

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

processingInstruction

public void processingInstruction(String target,
                                  CharSequence data,
                                  int locationId,
                                  int properties)
                           throws XPathException
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 "?>")
Throws:
XPathException

startContent

public void startContent()
                  throws XPathException
Start element content (called after all the attributes and namespaces have been processed)

Specified by:
startContent in interface Receiver
Overrides:
startContent in class ProxyReceiver
Throws:
XPathException

addWatch

public void addWatch(Watch watch)
Add a new Watch. This is associated with the current level in the element stack, and is automatically dropped when the current element goes out of scope.

Parameters:
watch - the watch to be added

getURIForPrefix

public String getURIForPrefix(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. May be the zero-length string, indicating that there is no prefix. This indicates either the default namespace or the null namespace, depending on the value of useDefault.
useDefault - true if the default namespace is to be used when the prefix is "". If false, the method returns "" when the prefix is "".
Returns:
the uri for the namespace, or null if the prefix is not in scope. The "null namespace" is represented by the pseudo-URI "".

iteratePrefixes

public Iterator iteratePrefixes()
Description copied from interface: NamespaceResolver
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

usesTypeAnnotations

public boolean usesTypeAnnotations()
Ask whether this Receiver (or the downstream pipeline) makes any use of the type annotations supplied on element and attribute events

Specified by:
usesTypeAnnotations in interface Receiver
Overrides:
usesTypeAnnotations in class ProxyReceiver
Returns:
true if the Receiver makes any use of this information. If false, the caller may supply untyped nodes instead of supplying the type annotation


Copyright (c) Saxonica Limited. All rights reserved.