Glad it worked out. Thanks for sharing this info back with the list.
Gary
> Christopher Raber wrote:
>
> Gary,
>
> Thanks for the pointers. A little sharing for the benefit of others
> that might struggle with this too:
>
> I did a short-cut version of what you suggested:
>
> // Added to hook in my EntityResolver
> InputSource inputSource = new InputSource(reader);
>
> XMLReader xmlReader =
> XMLReaderFactory.createXMLReader();
>
> xmlReader.setEntityResolver(entityResolver);
> // END Added to hook in my EntityResolver
>
> SAXSource saxSource = new SAXSource(xmlReader,
> inputSource);
>
> transformer.transform(saxSource, new
> StreamResult(xalanOutStream));
>
> Where enityResolver is an instance of MyEntityResolver:
>
> public class MyEntityResolver implements
> org.xml.sax.EntityResolver {
>
> // Maintains a cache of entities so they only have to be
> fetched once.
> // Each cache entry contains a byte array representing the
> contents of
> // the entity, keyed by systemId.
> Map entityCache;
>
> // Constructor
> public MyEntityResolver(){
> // Initialize entityCache. Synchronized because multiple
> threads may be reading/writing the cache...
> entityCache = Collections.synchronizedMap(new HashMap());
> }
>
> // resolve and entity based on its systemId. Not sure what
> publicId is for here?
> public org.xml.sax.InputSource resolveEntity (String publicId,
> String systemId)
> throws org.xml.sax.SAXException, java.io.IOException
> {
>
> BufferedInputStream sourceIn;
>
> // Look in cache to see if we have already fetched this
> baby before.
> byte bytesIn[] = (byte[])entityCache.get(systemId);
>
> // If not previously fetched, fetch and cache.
> if(bytesIn == null){
>
> // Look in the configuration to see if this entity has
> been mapped to a local copy.
> String localCopy = config.getEntity(systemId);
> if(localCopy != null){
> // return a special input source
> String localFileName =
> config.getCachedEntityDir()+localCopy;
> sourceIn = new BufferedInputStream(new
> FileInputStream(localFileName));
> } else {
> // Assumes the systemId is a URL...
> URL u = new URL(systemId);
> sourceIn = new
> BufferedInputStream(u.openStream());
> }
>
> // Read the bytes from the entity into a byte array
> and cache it.
> // This assumes available() returns the total number
> of bytes available
> // in the underlying resource.
> int numBytes = sourceIn.available();
> bytesIn = new byte[numBytes];
> int offset = 0;
> while (numBytes > 0){
> int numBytesRead = sourceIn.read(bytesIn, offset,
> numBytes);
> numBytes -= numBytesRead;
> offset += numBytesRead;
> }
> // Cache bytes for this entity...
> entityCache.put(systemId, bytesIn);
> }
> return new org.xml.sax.InputSource(new
> ByteArrayInputStream(bytesIn));
> }
> }
>
> MyEntityResolver does the following:
>
> - Looks in local storage for entities that are specified in its
> configuration. The config object above contains this information which
> was read from an XML config file...
>
> - Otherwise fetches the entity via its URL.
> - Caches the bytes of each entity for quick retrieval. IO to the
> source entity is only done once.
>
> Thanks for the suggestions!
>
> Regards,
>
> -Chris.
>
> Chris Raber, Systems Engineer, AvantGo Inc.
> v: 248-554-9330, cell: 810-839-3684
> http://www.avantgo.com/
>
> -----Original Message-----
> From: Gary L Peskin [mailto:[EMAIL PROTECTED]
> Sent: Thursday, July 26, 2001 12:26 AM
> To: Raber Chris
> Cc: [EMAIL PROTECTED]
> Subject: Re: How to turn of validation and resolution of DTD entities?
>
> Chris --
>
> There are a few things you need to consider when using
> EntityResolvers:
> (1) Two DOM (or DTM) trees are built: one for the stylesheet and one
>
> for the input document. Do you want an EntityResolver for both or do
> you only need it for one or the other? I'm going to assume in this
> example that you only want it for the input document. If you need it
> for the stylesheet, we'll have to jazz up this example.
> (2) At stylesheet creation time, additional stylesheets can be
> brought
> in using xsl:include and xsl:import. New readers are created for
> these
> things that don't use your EntityResolver. To trap this, you'll need
> to
> create a URIResolver that creates and returns a SAXSource that has
> your
> EntityResolver hooked into that XMLReader. The same holds true for
> XML
> input documents brought in at runtime with the document() function.
>
> So, for this simple example, I'll assume that you only want the
> EntityResolver at runtime and that there are no input documents
> brought
> in with the document() function.
>
> I'd code it like this (none of this is tested but should work :)).
> It's
> taken more or less from the "Usage Patterns" page at
> http://xml.apache.org/xalan-j/usagepatterns.html#sax
>
> import javax.xml.transform.TransformerFactory;
> import javax.xml.transform.sax.SAXTransformerFactory;
> import javax.xml.transform.sax.TransformerHandler;
> import org.xml.sax.XMLReader;
> import org.xml.sax.helpers.XMLReaderFactory.createXMLReader
> import org.apache.xalan.serialize.SerializerFactory;
> import org.apache.xalan.serialize.Serializer;
> import org.apache.xalan.templates.OutputProperties;
> import javax.xml.transform.Result;
> import javax.xml.transform.sax.SAXResult
>
> // Instantiate a TransformerFactory.
> TransformerFactory tFactory = TransformerFactory.newInstance();
>
> // Cast the TransformerFactory to SAXTransformerFactory.
> SAXTransformerFactory saxTFactory = (SAXTransformerFactory) Factory;
>
> // Create a Transformer ContentHandler to handle transformation of the
>
> XML Source
> TransformerHandler transformerHandler
> = saxTFactory.newTransformerHandler(new
> StreamSource("foo.xsl"));
>
> // Create an XMLReader and set its ContentHandler.
> XMLReader reader = XMLReaderFactory.createXMLReader();
> reader.setContentHandler(transformerHandler);
>
> // Set the ContentHandler to also function as a LexicalHandler, which
> // can process "lexical" events (such as comments and CDATA).
> reader.setProperty("http://xml.org/sax/properties/lexical-handler";,
> transformerHandler);
>
> // Set your EntityResolver into the reader
> reader.setEntityResolver(myEntityResolver);
>
> // Set up a Serializer to serialize the Result to a file.
> Serializer serializer = SerializerFactory.getSerializer
>
> (OutputProperties.getDefaultMethodProperties("xml"));
> serializer.setOutputStream(new java.io.FileOutputStream("foo.out"));
>
> // The Serializer functions as a SAX ContentHandler.
> Result result = new SAXResult(serializer.asContentHandler());
> transformerHandler.setResult(result);
>
> // Parse the XML input document.
> reader.parse("foo.xml");
>
> HTH,
> Gary
>
> Raber Chris wrote:
> >
> > I have a need to turn off resolution of DTD entities
> > when not connected to a network. Also I am thinking
> > that hitting http://www.w3.org/ every time we bump
> > into a DTD reference is a lot of overhead anyway. =:-o
> >
> > Based on a bit of Googling, it appears that
> > implementing an EntityResolver that redirects remote
> > TCP/IP destinations to a local cache is the ticket. If
> > there is another/easier way, please advise.
> >
> > Currently I am using StreamSource and StreamResult as
> > arguments to Transformer.transform, which is most
> > convenient. I'd like to avoid hooking together an
> > underlying parser, etc., if possible. I've really
> > appreciated the simplcity of using the higher level
> > Trax apis, and would like to stay there if I can.
> > Simple good...
> >
> > Is there a way to hook in my own
> > org.xml.sax.EntityResolver via a property, or must I
> > instantiate my own underlying SAX/DOM handlers... and
> > explictly call setEntityResolver an the XMLReaders?
> >
> > If the latter, can someone provide basic instructions
> > on how to string this together? Is the SAX2SAX example
> > a good place to start?
> >
> > And does anyone have an example EntityResolver they
> > would be willing to share?
> >
> > TIA,
> >
> > -Chris.
> >
> > PS: It would be real cool if it were possible to hook
> > this via property settings...
> >
> > __________________________________________________
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