All Packages  Class Hierarchy  This Package  Previous  Next  Index

Interface com.microstar.xml.XmlHandler

public interface XmlHandler
XML Processing Interface.

Whenever you parse an XML document, you must provide an object from a class that implements this interface to receive the parsing events.

If you do not want to implement this entire interface, you can extend the HandlerBase convenience class and then implement only what you need.

If you are using SAX, you should implement the SAX handler interfaces rather than this one.

Version:
1.1
Author:
Copyright (c) 1997, 1998 by Microstar Software Ltd., written by David Megginson <dmeggins@microstar.com>
See Also:
XmlParser, HandlerBase, EntityHandler, DocumentHandler, ErrorHandler

Method Index

 o attribute(String, String, boolean)
Attribute.
 o charData(char[], int, int)
Character data.
 o doctypeDecl(String, String, String)
Document type declaration.
 o endDocument()
End the document.
 o endElement(String)
End an element.
 o endExternalEntity(String)
End an external entity.
 o error(String, String, int, int)
Fatal XML parsing error.
 o ignorableWhitespace(char[], int, int)
Ignorable whitespace.
 o processingInstruction(String, String)
Processing instruction.
 o resolveEntity(String, String)
Resolve an External Entity.
 o startDocument()
Start the document.
 o startElement(String)
Start an element.
 o startExternalEntity(String)
Begin an external entity.

Methods

 o startDocument
 public abstract void startDocument() throws Exception
Start the document.

Ælfred will call this method just before it attempts to read the first entity (the root of the document). It is guaranteed that this will be the first method called.

Throws: Exception
The handler may throw any exception.
See Also:
endDocument
 o endDocument
 public abstract void endDocument() throws Exception
End the document.

Ælfred will call this method once, when it has finished parsing the XML document. It is guaranteed that this will be the last method called.

Throws: Exception
The handler may throw any exception.
See Also:
startDocument
 o resolveEntity
 public abstract Object resolveEntity(String publicId,
                                      String systemId) throws Exception
Resolve an External Entity.

Give the handler a chance to redirect external entities to different URIs. Ælfred will call this method for the top-level document entity, for external text (XML) entities, and the external DTD subset (if any).

Parameters:
publicId - The public identifier, or null if none was supplied.
systemId - The system identifier.
Returns:
The replacement system identifier, or null to use the default.
Throws: Exception
The handler may throw any exception.
See Also:
startExternalEntity, endExternalEntity
 o startExternalEntity
 public abstract void startExternalEntity(String systemId) throws Exception
Begin an external entity.

Ælfred will call this method at the beginning of each external entity, including the top-level document entity and the external DTD subset (if any).

If necessary, you can use this method to track the location of the current entity so that you can resolve relative URIs correctly.

Parameters:
systemId - The URI of the external entity that is starting.
Throws: Exception
The handler may throw any exception.
See Also:
endExternalEntity, resolveEntity
 o endExternalEntity
 public abstract void endExternalEntity(String systemId) throws Exception
End an external entity.

Ælfred will call this method at the end of each external entity, including the top-level document entity and the external DTD subset.

If necessary, you can use this method to track the location of the current entity so that you can resolve relative URIs correctly.

Parameters:
systemId - The URI of the external entity that is ending.
Throws: Exception
The handler may throw any exception.
See Also:
startExternalEntity, resolveEntity
 o doctypeDecl
 public abstract void doctypeDecl(String name,
                                  String publicId,
                                  String systemId) throws Exception
Document type declaration.

Ælfred will call this method when or if it encounters the document type (DOCTYPE) declaration.

Please note that the public and system identifiers will not always be a reliable indication of the DTD in use.

Parameters:
name - The document type name.
publicId - The public identifier, or null if unspecified.
systemId - The system identifier, or null if unspecified.
Throws: Exception
The handler may throw any exception.
 o attribute
 public abstract void attribute(String aname,
                                String value,
                                boolean isSpecified) throws Exception
Attribute.

Ælfred will call this method once for each attribute (specified or defaulted) before reporting a startElement event. It is up to your handler to collect the attributes, if necessary.

You may use XmlParser.getAttributeType() to find the attribute's declared type.

Parameters:
name - The name of the attribute.
type - The type of the attribute (see below).
value - The value of the attribute, or null if the attribute is #IMPLIED.
isSpecified - True if the value was specified, false if it was defaulted from the DTD.
Throws: Exception
The handler may throw any exception.
See Also:
startElement, declaredAttributes, getAttributeType, getAttributeDefaultValue
 o startElement
 public abstract void startElement(String elname) throws Exception
Start an element.

Ælfred will call this method at the beginning of each element. By the time this is called, all of the attributes for the element will already have been reported using the attribute method.

Parameters:
elname - The element type name.
Throws: Exception
The handler may throw any exception.
See Also:
attribute, endElement, declaredElements, getElementContentType
 o endElement
 public abstract void endElement(String elname) throws Exception
End an element.

Ælfred will call this method at the end of each element (including EMPTY elements).

Parameters:
elname - The element type name.
Throws: Exception
The handler may throw any exception.
See Also:
startElement, declaredElements, getElementContentType
 o charData
 public abstract void charData(char ch[],
                               int start,
                               int length) throws Exception
Character data.

Ælfred will call this method once for each chunk of character data found in the contents of elements. Note that the parser may break up a long sequence of characters into smaller chunks and call this method once for each chunk.

Do not attempt to read more than length characters from the array, or to read before the start position.

Parameters:
ch - The character data.
start - The starting position in the array.
length - The number of characters available.
Throws: Exception
The handler may throw any exception.
 o ignorableWhitespace
 public abstract void ignorableWhitespace(char ch[],
                                          int start,
                                          int length) throws Exception
Ignorable whitespace.

Ælfred will call this method once for each sequence of ignorable whitespace in element content (never in mixed content).

For details, see section 2.10 of the XML 1.0 recommendation.

Do not attempt to read more than length characters from the array or to read before the start position.

Parameters:
ch - The literal whitespace characters.
start - The starting position in the array.
length - The number of whitespace characters available.
Throws: Exception
The handler may throw any exception.
 o processingInstruction
 public abstract void processingInstruction(String target,
                                            String data) throws Exception
Processing instruction.

Ælfred will call this method once for each processing instruction. Note that processing instructions may appear outside of the top-level element. The

Parameters:
target - The target (the name at the start of the PI).
data - The data, if any (the rest of the PI).
Throws: Exception
The handler may throw any exception.
 o error
 public abstract void error(String message,
                            String systemId,
                            int line,
                            int column) throws Exception
Fatal XML parsing error.

Ælfred will call this method whenever it encounters a serious error. The parser will attempt to continue past this point so that you can find more possible error points, but if this method is called you should assume that the document is corrupt and you should not try to use its contents.

Note that you can use the XmlException class to encapsulate all of the information provided, though the use of the class is not mandatory.

Parameters:
message - The error message.
systemId - The system identifier of the entity that contains the error.
line - The approximate line number of the error.
column - The approximate column number of the error.
Throws: Exception
The handler may throw any exception.
See Also:
XmlException

All Packages  Class Hierarchy  This Package  Previous  Next  Index