org.apache.xml.resolver.readers
Class DOMCatalogReader
- CatalogReader
public class DOMCatalogReader
A DOM-based CatalogReader.
This class is used to read XML Catalogs using the DOM. This reader
has an advantage over the SAX-based reader that it can analyze the
DOM tree rather than simply a series of SAX events. It has the disadvantage
that it requires all of the code necessary to build and walk a DOM
tree.
Since the choice of CatalogReaders (in the InputStream case) can only
be made on the basis of MIME type, the following problem occurs: only
one CatalogReader can exist for all XML mime types. In order to get
around this problem, the DOMCatalogReader relies on a set of external
CatalogParsers to actually build the catalog.
The selection of CatalogParsers is made on the basis of the QName
of the root element of the document.
This class requires the
Java API for XML Parsing.
protected Hashtable | namespaceMap - Mapping table from QNames to CatalogParser classes.
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String | getCatalogParser(String namespaceURI, String rootElement) - Get the name of the parser class for a given catalog type.
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void | readCatalog(Catalog catalog, InputStream is) - Read a catalog from an input stream.
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void | readCatalog(Catalog catalog, String fileUrl) - Read the catalog behind the specified URL.
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void | setCatalogParser(String namespaceURI, String rootElement, String parserClass) - Add a new parser to the reader.
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namespaceMap
protected Hashtable namespaceMap
Mapping table from QNames to CatalogParser classes.
Each key in this hash table has the form "elementname"
or "{namespaceuri}elementname". The former is used if the
namespace URI is null.
DOMCatalogReader
public DOMCatalogReader()
Null constructor; something for subclasses to call.
getCatalogParser
public String getCatalogParser(String namespaceURI,
String rootElement)
Get the name of the parser class for a given catalog type.
This method returns the parserClass associated with the
namespaceURI/rootElement names specified.
namespaceURI
- The namespace URI. Not the prefix.rootElement
- The name of the root element.
readCatalog
public void readCatalog(Catalog catalog,
InputStream is)
throws IOException,
CatalogException
Read a catalog from an input stream.
This class reads a catalog from an input stream:
- Based on the QName of the root element, it determines which
parser to instantiate for this catalog.
- It constructs a DOM Document from the catalog and
- For each child of the root node, it calls the parser's
parseCatalogEntry method. This method is expected to make
appropriate calls back into the catalog to add entries for the
entries in the catalog. It is free to do this in whatever manner
is appropriate (perhaps using just the node passed in, perhaps
wandering arbitrarily throughout the tree).
- readCatalog in interface CatalogReader
catalog
- The catalog for which this reader is called.is
- The input stream that is to be read.
readCatalog
public void readCatalog(Catalog catalog,
String fileUrl)
throws MalformedURLException,
IOException,
CatalogException
Read the catalog behind the specified URL.
- readCatalog in interface CatalogReader
catalog
- The catalog for which we are reading.fileUrl
- The URL of the document that should be read.
setCatalogParser
public void setCatalogParser(String namespaceURI,
String rootElement,
String parserClass)
Add a new parser to the reader.
This method associates the specified parserClass with the
namespaceURI/rootElement names specified.
namespaceURI
- The namespace URI. Not the prefix.rootElement
- The name of the root element.parserClass
- The name of the parserClass to instantiate
for this kind of catalog.
Copyright B) 2001-2003 Apache Software Foundation. All Rights Reserved.