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:

org.xml.sax.ContentHandler, org.xml.sax.DTDHandler, org.xml.sax.EntityResolver, org.xml.sax.ErrorHandler

Direct Known Subclasses:

XHTMLContentHandler

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 spaces.

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

protected static interface

SafeContentHandler.Output Internal interface that allows both character and ignorable whitespace content to be filtered the same way.

Constructor Summary

SafeContentHandler(org.xml.sax.ContentHandler handler)

Method Summary

void	characters(char[] ch, int start, int length)
void	ignorableWhitespace(char[] ch, int start, int length)
protected boolean	isInvalid(char ch) Checks whether the given character (more accurately a UTF-16 code unit) is an invalid XML character and should be replaced for output.
protected void	writeReplacement(SafeContentHandler.Output output) Outputs the replacement for an invalid character.

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

endDocument, endElement, endPrefixMapping, handleException, processingInstruction, setContentHandler, setDocumentLocator, skippedEntity, startDocument, startElement, 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(org.xml.sax.ContentHandler handler)

Method Detail

isInvalid

protected boolean isInvalid(char ch)

Checks whether the given character (more accurately a UTF-16 code unit) 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.

Parameters:

ch - character

Returns:

true if the character should be replaced, false otherwise

writeReplacement

protected void writeReplacement(SafeContentHandler.Output output)
                         throws org.xml.sax.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:

org.xml.sax.SAXException - if the replacement could not be written

characters

public void characters(char[] ch,
                       int start,
                       int length)
                throws org.xml.sax.SAXException

Specified by:

characters in interface org.xml.sax.ContentHandler

Overrides:

characters in class ContentHandlerDecorator

Throws:

org.xml.sax.SAXException

ignorableWhitespace

public void ignorableWhitespace(char[] ch,
                                int start,
                                int length)
                         throws org.xml.sax.SAXException

Specified by:

ignorableWhitespace in interface org.xml.sax.ContentHandler

Overrides:

ignorableWhitespace in class ContentHandlerDecorator

Throws:

org.xml.sax.SAXException