Interface IEntityResolver

This module, both source code and documentation, is in the Public Domain, and comes with NO WARRANTY. Seehttp://www.saxproject.org for further information.

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 EntityResolver property.

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 specialised 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";:

public class MyResolver : IEntityResolver 
{
    public InputSource ResolveEntity (string publicId, string systemId)
    {
        if (systemId.Equals("http://www.myhost.com/today", StringComparison.Ordinal))
        {
            // return a special input source
            MyReader reader = new MyReader();
            return new InputSource(reader);
        }
        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).