Using the DTDHandler and EntityResolver
In this section, we discuss the two remaining SAX event handlers: DTDHandler and EntityResolver. The DTDHandler is invoked when the DTD encounters an unparsed entity or a notation declaration. The EntityResolver comes into play when a URN (public ID) must be resolved to a URL (system ID).
The DTDHandler API
In Choosing Your Parser Implementation (page 155) you saw a method for referencing a file that contains binary data, such as an image file, using MIME data types. That is the simplest, most extensible mechanism. For compatibility with older SGML-style data, though, it is also possible to define an unparsed entity.
The NDATA keyword defines an unparsed entity:
<!ENTITY myEntity SYSTEM "..URL.." NDATA ...Get The J2EE™ Tutorial Second Edition now with the O’Reilly learning platform.
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