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package com.sun.enterprise.config.serverbeans.validation;

import java.util.Stack;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.XMLFilter;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.XMLFilterImpl;



/**
 * FrameHolderBuilder.java
 * Instances of the class are responsible for handling a SAX input
 * stream to build a series of connected Frames to hold the
 * system-property definitions found inside the XML. 
 *
 * The Frames are connected by an inheritance pattern - it is this
 * class that knows what that inheritance pattern is. As of the time
 * of writing the pattern is:
 * <verbatim>
 * server [-> cluster] -> config -> domain
 * </verbatim>
 * With the cluster inheritance being optional, and only occuring when
 * a cluster refers to a server. (So, a server might look as if its
 * inheriting from one config, but a cluster can override the
 * server's own settings and cause the server to inherit from the
 * cluster and thus from some other config). 
 *
 * The inheritance hierarchy between configs and domains is
 * implicit. Between the other elements it is explicit, and is
 * achieved through the XML attributes "config-ref", "server-ref".
 *
 * This system will function even if the XML is quite poorly formed,
 * but the results will be peculiar, to say the least! The best
 * debugging method is to extract each frame from the resulting
 * FrameHolder and print it out - that gives you a pretty good picture
 * of what the inheritance tree looks like (at least in terms of
 * properties!).
 *
 * @author <a href="mailto:toby.h.ferguson@sun.com">Toby H Ferguson</a>
 * @version $Revision: 1.4 $
 */

// Upon revisiting this code I can't help but believe that this class
// should be called something slightly different. It appears to be an
// inheritance manager, and tightly tied into the Framer concept. I'm
// unsure why I built it this way!
public class FrameHolderBuilder extends Framer
{
    protected final Frame getClusterFrame(Attributes atts){
        final Frame f = super.getClusterFrame(atts);
        inheritFromConfigPerhaps(f, atts);
//         final String sr = atts.getValue(NAMESPACE, SERVER_REF);
//         if (sr != null){
//             frameHolder.getServerFrame(sr).inheritFrom(f);
//         }
        return f;
    }

    protected final void handleStartServerRefEvent(Attributes atts){
        final String sr = atts.getValue(NAMESPACE, NAME);
        if (sr != null){
            frameHolder.getServerFrame(sr).inheritFrom(currentFrame());
        }
    }
    
    protected final Frame getConfigFrame(Attributes atts){
        final Frame f = super.getConfigFrame(atts);
        f.inheritFrom(frameHolder.getDomainFrame());
        return f;
    }
    
    protected final Frame getServerFrame(Attributes atts){
        final Frame f = super.getServerFrame(atts);
        return inheritFromConfigPerhaps(f, atts);
    }

    private final Frame inheritFromConfigPerhaps(Frame f, Attributes atts){
        final String cr = atts.getValue(NAMESPACE, CONFIG_REF);
        if (cr != null){
            f.inheritFrom(frameHolder.getConfigFrame(cr));
        }
        return f;
    }

}