gate.creole
Class CreoleXmlHandler

java.lang.Object
  org.xml.sax.helpers.DefaultHandler
      gate.creole.CreoleXmlHandler

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler

public class CreoleXmlHandler
extends DefaultHandler

This is a SAX handler for processing creole.xml files. It would have been better to write it using DOM or JDOM but.... Resource data objects are created and added to the CREOLE register. URLs for resource JAR files are added to the GATE class loader.

Field Summary

private SimpleErrorHandler	_seh This object indicates what to do when the parser encounts an error
private StringBuffer	contentBuffer This is used to capture all data within two tags before calling the actual characters method
private Stack	contentStack A stack to stuff PCDATA onto for reading back at element ends.
private URL	creoleFileUrl The URL to the creole.xml file being parsed.
private Attributes	currentAttributes The current element's attribute list
private FeatureMap	currentAutoinstanceParams This field represents the params map required for autoinstantiation Its a map from param name to param value.
private List	currentAutoinstances This field holds autoinstanceParams describing the resource that needs to be instantiated
private Parameter	currentParam The current parameter
private SortedMap<Integer,List<Parameter>>	currentParamDisjunction The current parameter disjunction.
private ParameterList	currentParamList The current parameter list
private static boolean	DEBUG Debug flag
private boolean	readCharacterStatus This is a variable that shows if characters have been read
private CreoleRegister	register The register object that we add ResourceData objects to during parsing.
private ResourceData	resourceData The current resource data object
private URL	sourceUrl The source URL of the directory file being parsed.

Constructor Summary

CreoleXmlHandler(CreoleRegister register, URL directoryUrl, URL creoleFileUrl)
Construction

Method Summary

private String	attributes2String(Attributes atts) A verboase method for Attributes
void	characters(char[] text, int start, int length) Called when the SAX parser encounts text (PCDATA) in the XML doc
void	charactersAction(char[] text, int start, int length) This method is called when all characters between specific tags have been read completely
private void	checkStack(String methodName, String elementName) Utility function to throw exceptions on stack errors.
protected List<Parameter>	currentFlattenedDisjunction() Flatten the currentParamDisjunction map into a single list ordered by priority.
void	endDocument() Called when the SAX parser encounts the end of the XML document
void	endElement(String uri, String qName, String elementName) Called when the SAX parser encounts the end of an XML element.
void	error(SAXParseException ex) Called for parse errors.
void	fatalError(SAXParseException ex) Called for fatal errors.
void	ignorableWhitespace(char[] ch, int start, int length) Called when the SAX parser encounts white space
void	startDocument() Called when the SAX parser encounts the beginning of the XML document
void	startElement(String uri, String qName, String elementName, Attributes atts) Called when the SAX parser encounts the beginning of an XML element
void	warning(SAXParseException ex) Called for warnings.

Methods inherited from class org.xml.sax.helpers.DefaultHandler

endPrefixMapping, notationDecl, processingInstruction, resolveEntity, setDocumentLocator, skippedEntity, startPrefixMapping, unparsedEntityDecl

Methods inherited from class java.lang.Object

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

Field Detail

contentStack

private Stack contentStack

A stack to stuff PCDATA onto for reading back at element ends. (Probably redundant to have a stack as we only push one item onto it. Probably. Ok, so I should check, but a) it works, b) I'm bald already and c) life is short.)

resourceData

private ResourceData resourceData

The current resource data object

currentParamList

private ParameterList currentParamList

The current parameter list

currentParamDisjunction

private SortedMap<Integer,List<Parameter>> currentParamDisjunction

The current parameter disjunction. This is a map where each key is a "priority" and the value is a list of parameters tagged with that priority. This map is flattened into a single list when all the parameters in a single disjunction have been processed, such that parameters with a smaller priority value are listed ahead of those with a larger value, and those with no explicit priority are listed last of all. Parameters at the same priority are listed in document order. This is not so useful when writing creole.xml files by hand but is necessary to ensure a predictable order when using CreoleParameter annotations. The GATE developer GUI offers the first listed (i.e. highest priority) parameter for each disjunction as the default option in the resource parameters dialog box.

currentParam

private Parameter currentParam

The current parameter

currentAttributes

private Attributes currentAttributes

The current element's attribute list

DEBUG

private static final boolean DEBUG

Debug flag

See Also:

Constant Field Values

sourceUrl

private URL sourceUrl

The source URL of the directory file being parsed.

creoleFileUrl

private URL creoleFileUrl

The URL to the creole.xml file being parsed.

_seh

private SimpleErrorHandler _seh

This object indicates what to do when the parser encounts an error

currentAutoinstanceParams

private FeatureMap currentAutoinstanceParams

This field represents the params map required for autoinstantiation Its a map from param name to param value.

currentAutoinstances

private List currentAutoinstances

This field holds autoinstanceParams describing the resource that needs to be instantiated

contentBuffer

private StringBuffer contentBuffer

This is used to capture all data within two tags before calling the actual characters method

readCharacterStatus

private boolean readCharacterStatus

This is a variable that shows if characters have been read

register

private CreoleRegister register

The register object that we add ResourceData objects to during parsing.

Constructor Detail

CreoleXmlHandler

public CreoleXmlHandler(CreoleRegister register,
                        URL directoryUrl,
                        URL creoleFileUrl)

Construction

Method Detail

startDocument

public void startDocument()
                   throws GateSaxException

Called when the SAX parser encounts the beginning of the XML document

Specified by:

startDocument in interface ContentHandler

Overrides:

startDocument in class DefaultHandler

Throws:

GateSaxException

endDocument

public void endDocument()
                 throws GateSaxException

Called when the SAX parser encounts the end of the XML document

Specified by:

endDocument in interface ContentHandler

Overrides:

endDocument in class DefaultHandler

Throws:

GateSaxException

attributes2String

private String attributes2String(Attributes atts)

A verboase method for Attributes

startElement

public void startElement(String uri,
                         String qName,
                         String elementName,
                         Attributes atts)
                  throws SAXException

Called when the SAX parser encounts the beginning of an XML element

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class DefaultHandler

Throws:

SAXException

checkStack

private void checkStack(String methodName,
                        String elementName)
                 throws GateSaxException

Utility function to throw exceptions on stack errors.

Throws:

GateSaxException

endElement

public void endElement(String uri,
                       String qName,
                       String elementName)
                throws GateSaxException,
                       SAXException

Called when the SAX parser encounts the end of an XML element. This is where ResourceData objects get values set, and where they are added to the CreoleRegister when we parsed their complete metadata entries.

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class DefaultHandler

Throws:

GateSaxException

SAXException

characters

public void characters(char[] text,
                       int start,
                       int length)
                throws SAXException

Called when the SAX parser encounts text (PCDATA) in the XML doc

Specified by:

characters in interface ContentHandler

Overrides:

characters in class DefaultHandler

Throws:

SAXException

charactersAction

public void charactersAction(char[] text,
                             int start,
                             int length)
                      throws SAXException

This method is called when all characters between specific tags have been read completely

Throws:

SAXException

currentFlattenedDisjunction

protected List<Parameter> currentFlattenedDisjunction()

Flatten the currentParamDisjunction map into a single list ordered by priority.

ignorableWhitespace

public void ignorableWhitespace(char[] ch,
                                int start,
                                int length)
                         throws SAXException

Called when the SAX parser encounts white space

Specified by:

ignorableWhitespace in interface ContentHandler

Overrides:

ignorableWhitespace in class DefaultHandler

Throws:

SAXException

error

public void error(SAXParseException ex)
           throws SAXException

Called for parse errors.

Specified by:

error in interface ErrorHandler

Overrides:

error in class DefaultHandler

Throws:

SAXException

fatalError

public void fatalError(SAXParseException ex)
                throws SAXException

Called for fatal errors.

Specified by:

fatalError in interface ErrorHandler

Overrides:

fatalError in class DefaultHandler

Throws:

SAXException

warning

public void warning(SAXParseException ex)
             throws SAXException

Called for warnings.

Specified by:

warning in interface ErrorHandler

Overrides:

warning in class DefaultHandler

Throws:

SAXException