org.jdom.input

Class SAXBuilder


public class SAXBuilder
extends java.lang.Object

Builds a JDOM document from files, streams, readers, URLs, or a SAX org.xml.sax.InputSource instance using a SAX parser. The builder uses a third-party SAX parser (chosen by JAXP by default, or you can choose manually) to handle the parsing duties and simply listens to the SAX events to construct a document. Details which SAX does not provide, such as whitespace outside the root element, are not represented in the JDOM document. Information about SAX can be found at http://www.saxproject.org.

Known issues: Relative paths for a DocType or EntityRef may be converted by the SAX parser into absolute paths.

Version:
$Revision: 1.92 $, $Date: 2007/11/10 05:29:00 $
Authors:
Jason Hunter
Brett McLaughlin
Dan Schaffer
Philip Nelson
Alex Rosen

Constructor Summary

SAXBuilder()
Creates a new SAXBuilder which will attempt to first locate a parser via JAXP, then will try to use a set of default SAX Drivers.
SAXBuilder(String saxDriverClass)
Creates a new SAXBuilder using the specified SAX parser.
SAXBuilder(String saxDriverClass, boolean validate)
Creates a new SAXBuilder using the specified SAX parser.
SAXBuilder(boolean validate)
Creates a new SAXBuilder which will attempt to first locate a parser via JAXP, then will try to use a set of default SAX Drivers.

Method Summary

Document
build(File file)
This builds a document from the supplied filename.
Document
build(InputSource in)
This builds a document from the supplied input source.
Document
build(InputStream in)
This builds a document from the supplied input stream.
Document
build(InputStream in, String systemId)
This builds a document from the supplied input stream.
Document
build(Reader characterStream)
This builds a document from the supplied Reader.
Document
build(Reader characterStream, String systemId)
This builds a document from the supplied Reader.
Document
build(String systemId)
This builds a document from the supplied URI.
Document
build(URL url)
This builds a document from the supplied URL.
protected void
configureContentHandler(SAXHandler contentHandler)
This configures the SAXHandler that will be used to build the Document.
protected void
configureParser(XMLReader parser, SAXHandler contentHandler)
This configures the XMLReader to be used for reading the XML document.
protected SAXHandler
createContentHandler()
This creates the SAXHandler that will be used to build the Document.
protected XMLReader
createParser()
This creates the XMLReader to be used for reading the XML document.
DTDHandler
getDTDHandler()
Returns the DTDHandler assigned, or null if none.
String
getDriverClass()
Returns the driver class assigned in the constructor, or null if none.
EntityResolver
getEntityResolver()
Returns the EntityResolver assigned, or null if none.
ErrorHandler
getErrorHandler()
Returns the ErrorHandler assigned, or null if none.
boolean
getExpandEntities()
Returns whether or not entities are being expanded into normal text content.
JDOMFactory
getFactory()
Returns the current JDOMFactory in use.
boolean
getIgnoringBoundaryWhitespace()
Returns whether or not the parser will elminate element content containing only whitespace.
boolean
getIgnoringElementContentWhitespace()
Returns whether element content whitespace is to be ignored during the build.
boolean
getReuseParser()
Returns whether the contained SAX parser instance is reused across multiple parses.
boolean
getValidation()
Returns whether validation is to be performed during the build.
XMLFilter
getXMLFilter()
Returns the XMLFilter used during parsing, or null if none.
void
setDTDHandler(DTDHandler dtdHandler)
This sets custom DTDHandler for the Builder.
void
setEntityResolver(EntityResolver entityResolver)
This sets custom EntityResolver for the Builder.
void
setErrorHandler(ErrorHandler errorHandler)
This sets custom ErrorHandler for the Builder.
void
setExpandEntities(boolean expand)
This sets whether or not to expand entities for the builder.
void
setFactory(JDOMFactory factory)
This sets a custom JDOMFactory for the builder.
void
setFeature(String name, boolean value)
This sets a feature on the SAX parser.
void
setIgnoringBoundaryWhitespace(boolean ignoringBoundaryWhite)
Specifies whether or not the parser should elminate boundary whitespace, a term that indicates whitespace-only text between element tags.
void
setIgnoringElementContentWhitespace(boolean ignoringWhite)
Specifies whether or not the parser should elminate whitespace in element content (sometimes known as "ignorable whitespace") when building the document.
void
setProperty(String name, Object value)
This sets a property on the SAX parser.
void
setReuseParser(boolean reuseParser)
Specifies whether this builder shall reuse the same SAX parser when performing subsequent parses or allocate a new parser for each parse.
void
setValidation(boolean validate)
This sets validation for the builder.
void
setXMLFilter(XMLFilter xmlFilter)
This sets a custom org.xml.sax.XMLFilter for the builder.

Constructor Details

SAXBuilder

public SAXBuilder()
Creates a new SAXBuilder which will attempt to first locate a parser via JAXP, then will try to use a set of default SAX Drivers. The underlying parser will not validate.

SAXBuilder

public SAXBuilder(String saxDriverClass)
Creates a new SAXBuilder using the specified SAX parser. The underlying parser will not validate.
Parameters:
saxDriverClass - String name of SAX Driver to use for parsing.

SAXBuilder

public SAXBuilder(String saxDriverClass,
                  boolean validate)
Creates a new SAXBuilder using the specified SAX parser. The underlying parser will validate or not according to the given parameter.
Parameters:
saxDriverClass - String name of SAX Driver to use for parsing.
validate - boolean indicating if validation should occur.

SAXBuilder

public SAXBuilder(boolean validate)
Creates a new SAXBuilder which will attempt to first locate a parser via JAXP, then will try to use a set of default SAX Drivers. The underlying parser will validate or not according to the given parameter.
Parameters:
validate - boolean indicating if validation should occur.

Method Details

build

public Document build(File file)
            throws JDOMException,
                   IOException
This builds a document from the supplied filename.
Parameters:
file - File to read from
Returns:
Document resultant Document object
Throws:
JDOMException - when errors occur in parsing

build

public Document build(InputSource in)
            throws JDOMException,
                   IOException
This builds a document from the supplied input source.
Parameters:
in - InputSource to read from
Returns:
Document resultant Document object
Throws:
JDOMException - when errors occur in parsing

build

public Document build(InputStream in)
            throws JDOMException,
                   IOException
This builds a document from the supplied input stream.
Parameters:
in - InputStream to read from
Returns:
Document resultant Document object
Throws:
JDOMException - when errors occur in parsing

build

public Document build(InputStream in,
                      String systemId)
            throws JDOMException,
                   IOException
This builds a document from the supplied input stream.
Parameters:
in - InputStream to read from.
systemId - base for resolving relative URIs
Returns:
Document resultant Document object
Throws:
JDOMException - when errors occur in parsing

build

public Document build(Reader characterStream)
            throws JDOMException,
                   IOException
This builds a document from the supplied Reader. It's the programmer's responsibility to make sure the reader matches the encoding of the file. It's often easier and safer to use an InputStream rather than a Reader, and to let the parser auto-detect the encoding from the XML declaration.
Parameters:
characterStream - Reader to read from
Returns:
Document resultant Document object
Throws:
JDOMException - when errors occur in parsing

build

public Document build(Reader characterStream,
                      String systemId)
            throws JDOMException,
                   IOException
This builds a document from the supplied Reader. It's the programmer's responsibility to make sure the reader matches the encoding of the file. It's often easier and safer to use an InputStream rather than a Reader, and to let the parser auto-detect the encoding from the XML declaration.
Parameters:
characterStream - Reader to read from.
systemId - base for resolving relative URIs
Returns:
Document resultant Document object
Throws:
JDOMException - when errors occur in parsing

build

public Document build(String systemId)
            throws JDOMException,
                   IOException
This builds a document from the supplied URI.
Parameters:
systemId - URI for the input
Returns:
Document resultant Document object
Throws:
JDOMException - when errors occur in parsing

build

public Document build(URL url)
            throws JDOMException,
                   IOException
This builds a document from the supplied URL.
Parameters:
url - URL to read from.
Returns:
Document - resultant Document object.
Throws:
JDOMException - when errors occur in parsing

configureContentHandler

protected void configureContentHandler(SAXHandler contentHandler)
This configures the SAXHandler that will be used to build the Document.

The default implementation simply passes through some configuration settings that were set on the SAXBuilder: setExpandEntities() and setIgnoringElementContentWhitespace().


configureParser

protected void configureParser(XMLReader parser,
                               SAXHandler contentHandler)
            throws JDOMException
This configures the XMLReader to be used for reading the XML document.

The default implementation sets various options on the given XMLReader, such as validation, DTD resolution, entity handlers, etc., according to the options that were set (e.g. via setEntityResolver) and set various SAX properties and features that are required for JDOM internals. These features may change in future releases, so change this behavior at your own risk.


createContentHandler

protected SAXHandler createContentHandler()
This creates the SAXHandler that will be used to build the Document.
Returns:
SAXHandler - resultant SAXHandler object.

createParser

protected XMLReader createParser()
            throws JDOMException
This creates the XMLReader to be used for reading the XML document.

The default behavior is to (1) use the saxDriverClass, if it has been set, (2) try to obtain a parser from JAXP, if it is available, and (3) if all else fails, use a hard-coded default parser (currently the Xerces parser). Subclasses may override this method to determine the parser to use in a different way.

Returns:
XMLReader - resultant XMLReader object.

getDTDHandler

public DTDHandler getDTDHandler()
Returns the DTDHandler assigned, or null if none.
Returns:
the DTDHandler assigned

getDriverClass

public String getDriverClass()
Returns the driver class assigned in the constructor, or null if none.
Returns:
the driver class assigned in the constructor

getEntityResolver

public EntityResolver getEntityResolver()
Returns the EntityResolver assigned, or null if none.
Returns:
the EntityResolver assigned

getErrorHandler

public ErrorHandler getErrorHandler()
Returns the ErrorHandler assigned, or null if none.
Returns:
the ErrorHandler assigned, or null if none

getExpandEntities

public boolean getExpandEntities()
Returns whether or not entities are being expanded into normal text content.
Returns:
whether entities are being expanded

getFactory

public JDOMFactory getFactory()
Returns the current JDOMFactory in use.
Returns:
the factory in use

getIgnoringBoundaryWhitespace

public boolean getIgnoringBoundaryWhitespace()
Returns whether or not the parser will elminate element content containing only whitespace.
Returns:
boolean - whether only whitespace content will be ignored during build.

getIgnoringElementContentWhitespace

public boolean getIgnoringElementContentWhitespace()
Returns whether element content whitespace is to be ignored during the build.
Returns:
whether element content whitespace is to be ignored during the build

getReuseParser

public boolean getReuseParser()
Returns whether the contained SAX parser instance is reused across multiple parses. The default is true.
Returns:
whether the contained SAX parser instance is reused across multiple parses

getValidation

public boolean getValidation()
Returns whether validation is to be performed during the build.
Returns:
whether validation is to be performed during the build

getXMLFilter

public XMLFilter getXMLFilter()
Returns the XMLFilter used during parsing, or null if none.
Returns:
the XMLFilter used during parsing

setDTDHandler

public void setDTDHandler(DTDHandler dtdHandler)
This sets custom DTDHandler for the Builder.
Parameters:
dtdHandler - DTDHandler

setEntityResolver

public void setEntityResolver(EntityResolver entityResolver)
This sets custom EntityResolver for the Builder.
Parameters:
entityResolver - EntityResolver

setErrorHandler

public void setErrorHandler(ErrorHandler errorHandler)
This sets custom ErrorHandler for the Builder.
Parameters:
errorHandler - ErrorHandler

setExpandEntities

public void setExpandEntities(boolean expand)
This sets whether or not to expand entities for the builder. A true means to expand entities as normal content. A false means to leave entities unexpanded as EntityRef objects. The default is true.

When this setting is false, the internal DTD subset is retained; when this setting is true, the internal DTD subset is not retained.

Note that Xerces (at least up to 1.4.4) has a bug where entities in attribute values will be misreported if this flag is turned off, resulting in entities to appear within element content. When turning entity expansion off either avoid entities in attribute values, or use another parser like Crimson. http://nagoya.apache.org/bugzilla/show_bug.cgi?id=6111

Parameters:
expand - boolean indicating whether entity expansion should occur.

setFactory

public void setFactory(JDOMFactory factory)
This sets a custom JDOMFactory for the builder. Use this to build the tree with your own subclasses of the JDOM classes.
Parameters:
factory - JDOMFactory to use

setFeature

public void setFeature(String name,
                       boolean value)
This sets a feature on the SAX parser. See the SAX documentation for

NOTE: SAXBuilder requires that some particular features of the SAX parser be set up in certain ways for it to work properly. The list of such features may change in the future. Therefore, the use of this method may cause parsing to break, and even if it doesn't break anything today it might break parsing in a future JDOM version, because what JDOM parsers require may change over time. Use with caution.

Parameters:
name - The feature name, which is a fully-qualified URI.
value - The requested state of the feature (true or false).

setIgnoringBoundaryWhitespace

public void setIgnoringBoundaryWhitespace(boolean ignoringBoundaryWhite)
Specifies whether or not the parser should elminate boundary whitespace, a term that indicates whitespace-only text between element tags. This feature is a lot like setIgnoringElementContentWhitespace(boolean) but this feature is more aggressive and doesn't require validation be turned on. The setIgnoringElementContentWhitespace(boolean) call impacts the SAX parse process while this method impacts the JDOM build process, so it can be beneficial to turn both on for efficiency. For implementation efficiency, this method actually removes all whitespace-only text() nodes. That can, in some cases (like beteween an element tag and a comment), include whitespace that isn't just boundary whitespace. The default is false.
Parameters:
ignoringBoundaryWhite - Whether to ignore whitespace-only text noes

setIgnoringElementContentWhitespace

public void setIgnoringElementContentWhitespace(boolean ignoringWhite)
Specifies whether or not the parser should elminate whitespace in element content (sometimes known as "ignorable whitespace") when building the document. Only whitespace which is contained within element content that has an element only content model will be eliminated (see XML Rec 3.2.1). For this setting to take effect requires that validation be turned on. The default value of this setting is false.
Parameters:
ignoringWhite - Whether to ignore ignorable whitespace

setProperty

public void setProperty(String name,
                        Object value)
This sets a property on the SAX parser. See the SAX documentation for more information.

NOTE: SAXBuilder requires that some particular properties of the SAX parser be set up in certain ways for it to work properly. The list of such properties may change in the future. Therefore, the use of this method may cause parsing to break, and even if it doesn't break anything today it might break parsing in a future JDOM version, because what JDOM parsers require may change over time. Use with caution.

Parameters:
name - The property name, which is a fully-qualified URI.
value - The requested value for the property.

setReuseParser

public void setReuseParser(boolean reuseParser)
Specifies whether this builder shall reuse the same SAX parser when performing subsequent parses or allocate a new parser for each parse. The default value of this setting is true (parser reuse).

Note: As SAX parser instances are not thread safe, the parser reuse feature should not be used with SAXBuilder instances shared among threads.

Parameters:
reuseParser - Whether to reuse the SAX parser.

setValidation

public void setValidation(boolean validate)
This sets validation for the builder.
Parameters:
validate - boolean indicating whether validation should occur.

setXMLFilter

public void setXMLFilter(XMLFilter xmlFilter)
This sets a custom org.xml.sax.XMLFilter for the builder.
Parameters:
xmlFilter - the filter to use

Copyright B) 2007 Jason Hunter, Brett McLaughlin. All Rights Reserved.