org.apache.commons.jelly

Class XMLOutput

java.lang.Object

org.apache.commons.jelly.XMLOutput

All Implemented Interfaces:

ContentHandler, LexicalHandler

public class XMLOutput
extends Object
implements ContentHandler, LexicalHandler

XMLOutput is used to output XML events in a SAX-like manner. This also allows pipelining to be done such as in the Cocoon project.

Version:

$Revision: 225599 $

Author:

James Strachan

Field Summary

Fields

Modifier and Type	Field and Description
protected static String[]	LEXICAL_HANDLER_NAMES

Constructor Summary

Constructors

Constructor and Description
XMLOutput()
XMLOutput(ContentHandler contentHandler) The XML-output will relay the SAX events to the indicated contentHandler.
XMLOutput(ContentHandler contentHandler, LexicalHandler lexicalHandler) The XML-output will relay the SAX events to the indicated content-handler lexical-handler.

Method Summary

Methods

Modifier and Type	Method and Description
Writer	asWriter() Obtains the writer adapter.
void	characters(char[] ch, int start, int length) Receive notification of character data.
void	close() Provides a useful hook that implementations can use to close the underlying OutputStream or Writer.
void	comment(char[] ch, int start, int length) Report an XML comment anywhere in the document.
static XMLOutput	createDummyXMLOutput() returns an XMLOutput object that will discard all tag-generated XML events.
static XMLOutput	createXMLOutput(OutputStream out) Creates a text based XMLOutput which converts all XML events into text and writes to the underlying OutputStream.
static XMLOutput	createXMLOutput(OutputStream out, boolean escapeText) Creates a text based XMLOutput which converts all XML events into text and writes to the underlying OutputStream.
static XMLOutput	createXMLOutput(Writer writer) Creates a text based XMLOutput which converts all XML events into text and writes to the underlying Writer.
static XMLOutput	createXMLOutput(Writer writer, boolean escapeText) Creates a text based XMLOutput which converts all XML events into text and writes to the underlying Writer.
static XMLOutput	createXMLOutput(XMLReader xmlReader) Creates an XMLOutput from an existing SAX XMLReader.
protected static XMLOutput	createXMLOutput(org.dom4j.io.XMLWriter xmlWriter) Factory method to create a new XMLOutput from an XMLWriter
void	endCDATA() Report the end of a CDATA section.
void	endDocument() Receive notification of the end of a document.
void	endDTD() Report the end of DTD declarations.
void	endElement(String localName) Helper method for outputting an end element event for an element in no namespace.
void	endElement(String uri, String localName, String qName) Receive notification of the end of an element.
void	endEntity(String name) Report the end of an entity.
void	endPrefixMapping(String prefix) End the scope of a prefix-URI mapping.
void	flush() Flushes the underlying stream if XMLWriter or XMLOutput.
ContentHandler	getContentHandler()
LexicalHandler	getLexicalHandler()
void	ignorableWhitespace(char[] ch, int start, int length) Receive notification of ignorable whitespace in element content.
void	objectData(Object object) Pass data through the pipeline.
void	processingInstruction(String target, String data) Receive notification of a processing instruction.
void	setContentHandler(ContentHandler contentHandler) Sets the SAX ContentHandler to pipe SAX events into
void	setDocumentLocator(Locator locator) Receive an object for locating the origin of SAX document events.
void	setLexicalHandler(LexicalHandler lexicalHandler) Sets the SAX LexicalHandler to pipe SAX events into
void	skippedEntity(String name) Receive notification of a skipped entity.
void	startCDATA() Report the start of a CDATA section.
void	startDocument() Receive notification of the beginning of a document.
void	startDTD(String name, String publicId, String systemId) Report the start of DTD declarations, if any.
void	startElement(String localName) Helper method for outputting a start element event for an element in no namespace.
void	startElement(String localName, Attributes attributes) Helper method for outputting a start element event for an element in no namespace.
void	startElement(String uri, String localName, String qName, Attributes atts) Receive notification of the beginning of an element.
void	startEntity(String name) Report the beginning of some internal and external XML entities.
void	startPrefixMapping(String prefix, String uri) Begin the scope of a prefix-URI Namespace mapping.
String	toString()
void	write(String text) Outputs the given String as a piece of valid text in the XML event stream.
void	writeCDATA(String text) Outputs the given String as a piece of CDATA in the XML event stream.
void	writeComment(String text) Outputs a comment to the XML stream.

Methods inherited from class java.lang.Object

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

Field Detail

LEXICAL_HANDLER_NAMES

protected static final String[] LEXICAL_HANDLER_NAMES

Constructor Detail

XMLOutput

public XMLOutput()

XMLOutput

public XMLOutput(ContentHandler contentHandler)

The XML-output will relay the SAX events to the indicated contentHandler.

Parameters:

contentHandler -

XMLOutput

public XMLOutput(ContentHandler contentHandler,
         LexicalHandler lexicalHandler)

The XML-output will relay the SAX events to the indicated content-handler lexical-handler.

Parameters:

contentHandler -

lexicalHandler -

Method Detail

toString

public String toString()

Overrides:

toString in class Object

close

public void close()
           throws IOException

Provides a useful hook that implementations can use to close the underlying OutputStream or Writer.

Throws:

IOException

flush

public void flush()
           throws IOException

Flushes the underlying stream if XMLWriter or XMLOutput.

Throws:

IOException

createXMLOutput

public static XMLOutput createXMLOutput(XMLReader xmlReader)

Creates an XMLOutput from an existing SAX XMLReader.

createXMLOutput

public static XMLOutput createXMLOutput(Writer writer)

Creates a text based XMLOutput which converts all XML events into text and writes to the underlying Writer.

createXMLOutput

public static XMLOutput createXMLOutput(Writer writer,
                        boolean escapeText)

Creates a text based XMLOutput which converts all XML events into text and writes to the underlying Writer.

Parameters:

writer - is the writer to output to

escapeText - is whether or not text output will be escaped. This must be true if the underlying output is XML or could be false if the underlying output is textual.

createXMLOutput

public static XMLOutput createXMLOutput(OutputStream out)
                                 throws UnsupportedEncodingException

Creates a text based XMLOutput which converts all XML events into text and writes to the underlying OutputStream.

Throws:

UnsupportedEncodingException

createXMLOutput

public static XMLOutput createXMLOutput(OutputStream out,
                        boolean escapeText)
                                 throws UnsupportedEncodingException

Creates a text based XMLOutput which converts all XML events into text and writes to the underlying OutputStream.

Parameters:

out - is the output stream to write

escapeText - is whether or not text output will be escaped. This must be true if the underlying output is XML or could be false if the underlying output is textual.

Throws:

UnsupportedEncodingException - if the underlying write could not be created.

createDummyXMLOutput

public static XMLOutput createDummyXMLOutput()

returns an XMLOutput object that will discard all tag-generated XML events. Useful when tag output is not expected or not significant.

Returns:

a no-op XMLOutput

asWriter

public Writer asWriter()

Obtains the writer adapter. Writing to this Writer is equivalent of calling characters(char[], int, int) repeatedly.

write

public void write(String text)
           throws SAXException

Outputs the given String as a piece of valid text in the XML event stream. Any special XML characters should come out properly escaped.

Throws:

SAXException

writeCDATA

public void writeCDATA(String text)
                throws SAXException

Outputs the given String as a piece of CDATA in the XML event stream.

Throws:

SAXException

writeComment

public void writeComment(String text)
                  throws SAXException

Outputs a comment to the XML stream.

Throws:

SAXException

startElement

public void startElement(String localName)
                  throws SAXException

Helper method for outputting a start element event for an element in no namespace.

Throws:

SAXException

startElement

public void startElement(String localName,
                Attributes attributes)
                  throws SAXException

Helper method for outputting a start element event for an element in no namespace.

Throws:

SAXException

endElement

public void endElement(String localName)
                throws SAXException

Helper method for outputting an end element event for an element in no namespace.

Throws:

SAXException

setDocumentLocator

public void setDocumentLocator(Locator locator)

Receive an object for locating the origin of SAX document events.

SAX parsers are strongly encouraged (though not absolutely required) to supply a locator: if it does so, it must supply the locator to the application by invoking this method before invoking any of the other methods in the ContentHandler interface.

The locator allows the application to determine the end position of any document-related event, even if the parser is not reporting an error. Typically, the application will use this information for reporting its own errors (such as character content that does not match an application's business rules). The information returned by the locator is probably not sufficient for use with a search engine.

Note that the locator will return correct information only during the invocation of the events in this interface. The application should not attempt to use it at any other time.

Specified by:

setDocumentLocator in interface ContentHandler

Parameters:

locator - An object that can return the location of any SAX document event.

See Also:

Locator

startDocument

public void startDocument()
                   throws SAXException

Receive notification of the beginning of a document.

The SAX parser will invoke this method only once, before any other event callbacks (except for setDocumentLocator).

Specified by:

startDocument in interface ContentHandler

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

See Also:

endDocument()

endDocument

public void endDocument()
                 throws SAXException

Receive notification of the end of a document.

The SAX parser will invoke this method only once, and it will be the last method invoked during the parse. The parser shall not invoke this method until it has either abandoned parsing (because of an unrecoverable error) or reached the end of input.

Specified by:

endDocument in interface ContentHandler

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

See Also:

startDocument()

startPrefixMapping

public void startPrefixMapping(String prefix,
                      String uri)
                        throws SAXException

Begin the scope of a prefix-URI Namespace mapping.

The information from this event is not necessary for normal Namespace processing: the SAX XML reader will automatically replace prefixes for element and attribute names when the http://xml.org/sax/features/namespaces feature is true (the default).

There are cases, however, when applications need to use prefixes in character data or in attribute values, where they cannot safely be expanded automatically; the start/endPrefixMapping event supplies the information to the application to expand prefixes in those contexts itself, if necessary.

Note that start/endPrefixMapping events are not guaranteed to be properly nested relative to each other: all startPrefixMapping events will occur immediately before the corresponding startElement event, and all endPrefixMapping events will occur immediately after the corresponding endElement event, but their order is not otherwise guaranteed.

There should never be start/endPrefixMapping events for the "xml" prefix, since it is predeclared and immutable.

Specified by:

startPrefixMapping in interface ContentHandler

Parameters:

prefix - The Namespace prefix being declared. An empty string is used for the default element namespace, which has no prefix.

uri - The Namespace URI the prefix is mapped to.

Throws:

SAXException - The client may throw an exception during processing.

See Also:

endPrefixMapping(java.lang.String), startElement(java.lang.String)

endPrefixMapping

public void endPrefixMapping(String prefix)
                      throws SAXException

End the scope of a prefix-URI mapping.

See startPrefixMapping for details. These events will always occur immediately after the corresponding endElement event, but the order of endPrefixMapping events is not otherwise guaranteed.

Specified by:

endPrefixMapping in interface ContentHandler

Parameters:

prefix - The prefix that was being mapped. This is the empty string when a default mapping scope ends.

Throws:

SAXException - The client may throw an exception during processing.

See Also:

startPrefixMapping(java.lang.String, java.lang.String), endElement(java.lang.String)

startElement

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

Receive notification of the beginning of an element.

The Parser will invoke this method at the beginning of every element in the XML document; there will be a corresponding endElement event for every startElement event (even when the element is empty). All of the element's content will be reported, in order, before the corresponding endElement event.

This event allows up to three name components for each element:

1. the Namespace URI;
2. the local name; and
3. the qualified (prefixed) name.

Any or all of these may be provided, depending on the values of the http://xml.org/sax/features/namespaces and the http://xml.org/sax/features/namespace-prefixes properties:

• the Namespace URI and local name are required when the namespaces property is true (the default), and are optional when the namespaces property is false (if one is specified, both must be);
• the qualified name is required when the namespace-prefixes property is true, and is optional when the namespace-prefixes property is false (the default).

Note that the attribute list provided will contain only attributes with explicit values (specified or defaulted): #IMPLIED attributes will be omitted. The attribute list will contain attributes used for Namespace declarations (xmlns* attributes) only if the http://xml.org/sax/features/namespace-prefixes property is true (it is false by default, and support for a true value is optional).

Like characters(), attribute values may have characters that need more than one char value.

Specified by:

startElement in interface ContentHandler

Parameters:

uri - The Namespace URI, or the empty string if the element has no Namespace URI or if Namespace processing is not being performed.

localName - The local name (without prefix), or the empty string if Namespace processing is not being performed.

qName - The qualified name (with prefix), or the empty string if qualified names are not available.

atts - The attributes attached to the element. If there are no attributes, it shall be an empty Attributes object.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

See Also:

endElement(java.lang.String), Attributes

endElement

public void endElement(String uri,
              String localName,
              String qName)
                throws SAXException

Receive notification of the end of an element.

The SAX parser will invoke this method at the end of every element in the XML document; there will be a corresponding startElement event for every endElement event (even when the element is empty).

For information on the names, see startElement.

Specified by:

endElement in interface ContentHandler

Parameters:

uri - The Namespace URI, or the empty string if the element has no Namespace URI or if Namespace processing is not being performed.

localName - The local name (without prefix), or the empty string if Namespace processing is not being performed.

qName - The qualified XML 1.0 name (with prefix), or the empty string if qualified names are not available.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

characters

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

Receive notification of character data.

The Parser will call this method to report each chunk of character data. SAX parsers may return all contiguous character data in a single chunk, or they may split it into several chunks; however, all of the characters in any single event must come from the same external entity so that the Locator provides useful information.

The application must not attempt to read from the array outside of the specified range.

Individual characters may consist of more than one Java char value. There are two important cases where this happens, because characters can't be represented in just sixteen bits. In one case, characters are represented in a Surrogate Pair, using two special Unicode values. Such characters are in the so-called "Astral Planes", with a code point above U+FFFF. A second case involves composite characters, such as a base character combining with one or more accent characters.

Your code should not assume that algorithms using char-at-a-time idioms will be working in character units; in some cases they will split characters. This is relevant wherever XML permits arbitrary characters, such as attribute values, processing instruction data, and comments as well as in data reported from this method. It's also generally relevant whenever Java code manipulates internationalized text; the issue isn't unique to XML.

Note that some parsers will report whitespace in element content using the ignorableWhitespace method rather than this one (validating parsers must do so).

Specified by:

characters in interface ContentHandler

Parameters:

ch - The characters from the XML document.

start - The start position in the array.

length - The number of characters to read from the array.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

See Also:

ignorableWhitespace(char[], int, int), Locator

ignorableWhitespace

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

Receive notification of ignorable whitespace in element content.

Validating Parsers must use this method to report each chunk of whitespace in element content (see the W3C XML 1.0 recommendation, section 2.10): non-validating parsers may also use this method if they are capable of parsing and using content models.

SAX parsers may return all contiguous whitespace in a single chunk, or they may split it into several chunks; however, all of the characters in any single event must come from the same external entity, so that the Locator provides useful information.

The application must not attempt to read from the array outside of the specified range.

Specified by:

ignorableWhitespace in interface ContentHandler

Parameters:

ch - The characters from the XML document.

start - The start position in the array.

length - The number of characters to read from the array.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

See Also:

characters(char[], int, int)

processingInstruction

public void processingInstruction(String target,
                         String data)
                           throws SAXException

Receive notification of a processing instruction.

The Parser will invoke this method once for each processing instruction found: note that processing instructions may occur before or after the main document element.

A SAX parser must never report an XML declaration (XML 1.0, section 2.8) or a text declaration (XML 1.0, section 4.3.1) using this method.

Like characters(), processing instruction data may have characters that need more than one char value.

Specified by:

processingInstruction in interface ContentHandler

Parameters:

target - The processing instruction target.

data - The processing instruction data, or null if none was supplied. The data does not include any whitespace separating it from the target.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

skippedEntity

public void skippedEntity(String name)
                   throws SAXException

Receive notification of a skipped entity. This is not called for entity references within markup constructs such as element start tags or markup declarations. (The XML recommendation requires reporting skipped external entities. SAX also reports internal entity expansion/non-expansion, except within markup constructs.)

The Parser will invoke this method each time the entity is skipped. Non-validating processors may skip entities if they have not seen the declarations (because, for example, the entity was declared in an external DTD subset). All processors may skip external entities, depending on the values of the http://xml.org/sax/features/external-general-entities and the http://xml.org/sax/features/external-parameter-entities properties.

Specified by:

skippedEntity in interface ContentHandler

Parameters:

name - The name of the skipped entity. If it is a parameter entity, the name will begin with '%', and if it is the external DTD subset, it will be the string "[dtd]".

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

startDTD

public void startDTD(String name,
            String publicId,
            String systemId)
              throws SAXException

Report the start of DTD declarations, if any.

This method is intended to report the beginning of the DOCTYPE declaration; if the document has no DOCTYPE declaration, this method will not be invoked.

All declarations reported through DTDHandler or DeclHandler events must appear between the startDTD and endDTD events. Declarations are assumed to belong to the internal DTD subset unless they appear between startEntity and endEntity events. Comments and processing instructions from the DTD should also be reported between the startDTD and endDTD events, in their original order of (logical) occurrence; they are not required to appear in their correct locations relative to DTDHandler or DeclHandler events, however.

Note that the start/endDTD events will appear within the start/endDocument events from ContentHandler and before the first startElement event.

Specified by:

startDTD in interface LexicalHandler

Parameters:

name - The document type name.

publicId - The declared public identifier for the external DTD subset, or null if none was declared.

systemId - The declared system identifier for the external DTD subset, or null if none was declared. (Note that this is not resolved against the document base URI.)

Throws:

SAXException - The application may raise an exception.

See Also:

endDTD(), startEntity(java.lang.String)

endDTD

public void endDTD()
            throws SAXException

Report the end of DTD declarations.

This method is intended to report the end of the DOCTYPE declaration; if the document has no DOCTYPE declaration, this method will not be invoked.

Specified by:

endDTD in interface LexicalHandler

Throws:

SAXException - The application may raise an exception.

See Also:

startDTD(java.lang.String, java.lang.String, java.lang.String)

startEntity

public void startEntity(String name)
                 throws SAXException

Report the beginning of some internal and external XML entities.

The reporting of parameter entities (including the external DTD subset) is optional, and SAX2 drivers that report LexicalHandler events may not implement it; you can use the http://xml.org/sax/features/lexical-handler/parameter-entities feature to query or control the reporting of parameter entities.

General entities are reported with their regular names, parameter entities have '%' prepended to their names, and the external DTD subset has the pseudo-entity name "[dtd]".

When a SAX2 driver is providing these events, all other events must be properly nested within start/end entity events. There is no additional requirement that events from DeclHandler or DTDHandler be properly ordered.

Note that skipped entities will be reported through the skippedEntity event, which is part of the ContentHandler interface.

Because of the streaming event model that SAX uses, some entity boundaries cannot be reported under any circumstances:

• general entities within attribute values
• parameter entities within declarations

These will be silently expanded, with no indication of where the original entity boundaries were.

Note also that the boundaries of character references (which are not really entities anyway) are not reported.

All start/endEntity events must be properly nested.

Specified by:

startEntity in interface LexicalHandler

Parameters:

name - The name of the entity. If it is a parameter entity, the name will begin with '%', and if it is the external DTD subset, it will be "[dtd]".

Throws:

SAXException - The application may raise an exception.

See Also:

endEntity(java.lang.String), DeclHandler.internalEntityDecl(java.lang.String, java.lang.String), DeclHandler.externalEntityDecl(java.lang.String, java.lang.String, java.lang.String)

endEntity

public void endEntity(String name)
               throws SAXException

Report the end of an entity.

Specified by:

endEntity in interface LexicalHandler

Parameters:

name - The name of the entity that is ending.

Throws:

SAXException - The application may raise an exception.

See Also:

startEntity(java.lang.String)

startCDATA

public void startCDATA()
                throws SAXException

Report the start of a CDATA section.

The contents of the CDATA section will be reported through the regular characters event; this event is intended only to report the boundary.

Specified by:

startCDATA in interface LexicalHandler

Throws:

SAXException - The application may raise an exception.

See Also:

endCDATA()

endCDATA

public void endCDATA()
              throws SAXException

Report the end of a CDATA section.

Specified by:

endCDATA in interface LexicalHandler

Throws:

SAXException - The application may raise an exception.

See Also:

startCDATA()

comment

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

Report an XML comment anywhere in the document.

This callback will be used for comments inside or outside the document element, including comments in the external DTD subset (if read). Comments in the DTD must be properly nested inside start/endDTD and start/endEntity events (if used).

Specified by:

comment in interface LexicalHandler

Parameters:

ch - An array holding the characters in the comment.

start - The starting position in the array.

length - The number of characters to use from the array.

Throws:

SAXException - The application may raise an exception.

objectData

public void objectData(Object object)
                throws SAXException

Pass data through the pipeline. By default, this call is ignored. Subclasses are invited to use this as a way for children tags to pass data to their parent.

Parameters:

object - the data to pass

Throws:

SAXException - The application may raise an exception.

getContentHandler

public ContentHandler getContentHandler()

Returns:

the SAX ContentHandler to use to pipe SAX events into

setContentHandler

public void setContentHandler(ContentHandler contentHandler)

Sets the SAX ContentHandler to pipe SAX events into

Parameters:

contentHandler - is the new ContentHandler to use. This value cannot be null.

getLexicalHandler

public LexicalHandler getLexicalHandler()

Returns:

the SAX LexicalHandler to use to pipe SAX events into

setLexicalHandler

public void setLexicalHandler(LexicalHandler lexicalHandler)

Sets the SAX LexicalHandler to pipe SAX events into

Parameters:

lexicalHandler - is the new LexicalHandler to use. This value can be null.

createXMLOutput

protected static XMLOutput createXMLOutput(org.dom4j.io.XMLWriter xmlWriter)

Factory method to create a new XMLOutput from an XMLWriter