org.apache.tika.sax

Class SafeContentHandler

java.lang.Object

org.xml.sax.helpers.DefaultHandler

org.apache.tika.sax.ContentHandlerDecorator

org.apache.tika.sax.SafeContentHandler

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler

Direct Known Subclasses:

XHTMLContentHandler, XMPContentHandler

public class SafeContentHandler
extends ContentHandlerDecorator

Content handler decorator that makes sure that the character events (characters(char[], int, int) or ignorableWhitespace(char[], int, int)) passed to the decorated content handler contain only valid XML characters. All invalid characters are replaced with the Unicode replacement character U+FFFD (though a subclass may change this by overriding the writeReplacement(Output) method).

The XML standard defines the following Unicode character ranges as valid XML characters:

 #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
 

Note that currently this class only detects those invalid characters whose UTF-16 representation fits a single char. Also, this class does not ensure that the UTF-16 encoding of incoming characters is correct.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static interface	SafeContentHandler.Output Internal interface that allows both character and ignorable whitespace content to be filtered the same way.

Constructor Summary

Constructors

Constructor and Description
SafeContentHandler(ContentHandler handler)

Method Summary

Modifier and Type	Method and Description
void	characters(char[] ch, int start, int length)
void	endDocument()
void	endElement(String uri, String localName, String name)
void	ignorableWhitespace(char[] ch, int start, int length)
protected boolean	isInvalid(int ch) Checks whether the given Unicode character is an invalid XML character and should be replaced for output.
void	startElement(String uri, String localName, String name, Attributes atts)
protected void	writeReplacement(SafeContentHandler.Output output) Outputs the replacement for an invalid character.

Methods inherited from class org.apache.tika.sax.ContentHandlerDecorator

endPrefixMapping, handleException, processingInstruction, setContentHandler, setDocumentLocator, skippedEntity, startDocument, startPrefixMapping, toString

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

error, fatalError, notationDecl, resolveEntity, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

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

Constructor Detail

SafeContentHandler

public SafeContentHandler(ContentHandler handler)

Method Detail

isInvalid

protected boolean isInvalid(int ch)

Checks whether the given Unicode character is an invalid XML character and should be replaced for output. Subclasses can override this method to use an alternative definition of which characters should be replaced in the XML output. The default definition from the XML specification is:

 Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
 

Parameters:

ch - character

Returns:

true if the character should be replaced, false otherwise

writeReplacement

protected void writeReplacement(SafeContentHandler.Output output)
                         throws SAXException

Outputs the replacement for an invalid character. Subclasses can override this method to use a custom replacement.

Parameters:

output - where the replacement is written to

Throws:

SAXException - if the replacement could not be written

startElement

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

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class ContentHandlerDecorator

Throws:

SAXException

endElement

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

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class ContentHandlerDecorator

Throws:

SAXException

endDocument

public void endDocument()
                 throws SAXException

Specified by:

endDocument in interface ContentHandler

Overrides:

endDocument in class ContentHandlerDecorator

Throws:

SAXException

characters

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

Specified by:

characters in interface ContentHandler

Overrides:

characters in class ContentHandlerDecorator

Throws:

SAXException

ignorableWhitespace

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

Specified by:

ignorableWhitespace in interface ContentHandler

Overrides:

ignorableWhitespace in class ContentHandlerDecorator

Throws:

SAXException