Cross-Platform C++

ot::sax
class EntityResolver  (abstract)

#include "ot/sax/EntityResolver.h"

ot::ManagedObject ot::sax::DefaultHandler Basic interface for resolving entities.

If a SAX application needs to implement customized handling for external entities, it must implement this interface and register an instance with the SAX driver using the XMLReader::setEntityResolver() method.

The XML reader will then allow the application to intercept any external entities (including the external DTD subset and external parameter entities, if any) before including them.

Many SAX applications will not need to implement this interface, but it will be especially useful for applications that build XML documents from databases or other specialized input sources, or for applications that use URI types other than URLs.

The following resolver would provide the application with a special character stream for the entity with the system identifier http://www.myhost.com/today:

    #include "ot/sax/EntityResolver.h"
    #include "ot/sax/InputSource.h"
    
    using ot::sax::EntityResolver;
    using ot::sax::InputSource;

    class MyResolver : public EntityResolver
    {
        RefPtr<InputSource> resolveEntity(const String& publicId,
                                          const String& systemId)
        {
            if(systemId == OT_T("http://www.myhost.com/today"))
            {
                // return a special input source that reads characters
                // from a MyReader object
                return new InputSource(new MyReader);
            }
            else
            {
                // use the default behaviour
                return NULL;
            }
        }
    };

The application can also use this interface to redirect system identifiers to local URIs or to look up replacements in a catalog (possibly by using the public identifier).

See also:
XMLReader::setEntityResolver() , InputSource



Method Summary
 virtual RefPtr< InputSource > resolveEntity(const String& publicId, const String& systemId)=0
         Allow the application to resolve external entities.

Methods inherited from class ot::ManagedObject
addRef, getRefCount, onFinalRelease, operator=, release

Method Detail

resolveEntity

virtual RefPtr< InputSourceresolveEntity(const String& publicId,
                                            const String& systemId)=0
Allow the application to resolve external entities.

The Parser will call this method before opening any external entity except the top-level document entity (including the external DTD subset, external entities referenced within the DTD, and external entities referenced within the document element): the application may request that the parser resolve the entity itself, that it use an alternative URI, or that it use an entirely different input source.

Application writers can use this method to redirect external system identifiers to secure and/or local URIs, to look up public identifiers in a catalogue, or to read an entity from a database or other input source (including, for example, a dialog box).

If the system identifier is a URL, it will be fully resolved if the http://elcel.com/opentop/sax/features/resolve-entity-uris feature is set to true (the default).

Parameters:
publicId - The public identifier of the external entity being referenced, or the empty string if none was supplied.
systemId - The system identifier of the external entity being referenced.
Returns:
An InputSource object describing the new input source, or a null pointer to request that the parser open a regular URL connection to the system identifier.
Exceptions:
SAXException - The client may throw an exception during processing. If so, the SAX XML parser will stop parsing the current document.
See also:
InputSource


Cross-Platform C++

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