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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package com.sun.tools.internal.xjc.reader.internalizer;

import com.sun.xml.internal.bind.unmarshaller.DOMScanner;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.XMLFilterImpl;

Produces a complete series of SAX events from any DOM node
in the DOMForest.
 This class hides a logic of re-associating Locator to the generated SAX event stream. 
Author:

    Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)/**
 * Produces a complete series of SAX events from any DOM node
 * in the DOMForest.
 *
 * <p>
 * This class hides a logic of re-associating {@link Locator}
 * to the generated SAX event stream.
 *
 * @author
 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
 */
public class DOMForestScanner {

    private final DOMForest forest;

    
Scans DOM nodes of the given forest.
DOM node parameters to the scan method must be a part of
this forest.
/**
     * Scans DOM nodes of the given forest.
     *
     * DOM node parameters to the scan method must be a part of
     * this forest.
     */
    public DOMForestScanner( DOMForest _forest ) {
        this.forest = _forest;
    }

    
Generates the whole set of SAX events by treating
element e as if it's a root element.
/**
     * Generates the whole set of SAX events by treating
     * element e as if it's a root element.
     */
    public void scan( Element e, ContentHandler contentHandler ) throws SAXException {
        DOMScanner scanner = new DOMScanner();

        // insert the location resolver into the pipe line
        LocationResolver resolver = new LocationResolver(scanner);
        resolver.setContentHandler(contentHandler);

        // parse this DOM.
        scanner.setContentHandler(resolver);
        scanner.scan(e);
    }

    
Generates the whole set of SAX events from the given Document
in the DOMForest.
/**
     * Generates the whole set of SAX events from the given Document
     * in the DOMForest.
     */
    public void scan( Document d, ContentHandler contentHandler ) throws SAXException {
        scan( d.getDocumentElement(), contentHandler );
    }

    
Intercepts the invocation of the setDocumentLocator method
and passes itself as the locator.
If the client calls one of the methods on the Locator interface,
use the LocatorTable to resolve the source location.
/**
     * Intercepts the invocation of the setDocumentLocator method
     * and passes itself as the locator.
     *
     * If the client calls one of the methods on the Locator interface,
     * use the LocatorTable to resolve the source location.
     */
    private class LocationResolver extends XMLFilterImpl implements Locator {
        LocationResolver( DOMScanner _parent ) {
            this.parent = _parent;
        }

        private final DOMScanner parent;

        
Flag that tells us whether we are processing a start element event
or an end element event.
DOMScanner's getCurrentLocation method doesn't tell us which, but
this information is necessary to return the correct source line information.
Thus we set this flag appropriately before we pass an event to
the next ContentHandler, thereby making it possible to figure
out which location to return.
/**
         * Flag that tells us whether we are processing a start element event
         * or an end element event.
         *
         * DOMScanner's getCurrentLocation method doesn't tell us which, but
         * this information is necessary to return the correct source line information.
         *
         * Thus we set this flag appropriately before we pass an event to
         * the next ContentHandler, thereby making it possible to figure
         * out which location to return.
         */
        private boolean inStart = false;

        @Override
        public void setDocumentLocator(Locator locator) {
            // ignore one set by the parent.

            super.setDocumentLocator(this);
        }

        @Override
        public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
            inStart = false;
            super.endElement(namespaceURI, localName, qName);
        }

        @Override
        public void startElement(String namespaceURI, String localName, String qName, Attributes atts)
            throws SAXException {
            inStart = true;
            super.startElement(namespaceURI, localName, qName, atts);
        }

        private Locator findLocator() {
            Node n = parent.getCurrentLocation();
            if( n instanceof Element ) {
                Element e = (Element)n;
                if( inStart )
                    return forest.locatorTable.getStartLocation( e );
                else
                    return forest.locatorTable.getEndLocation( e );
            }
            return null;
        }

        //
        //
        // Locator methods
        //
        //
        public int getColumnNumber() {
            Locator l = findLocator();
            if(l!=null)     return l.getColumnNumber();
            return          -1;
        }

        public int getLineNumber() {
            Locator l = findLocator();
            if(l!=null)     return l.getLineNumber();
            return          -1;
        }

        public String getPublicId() {
            Locator l = findLocator();
            if(l!=null)     return l.getPublicId();
            return          null;
        }

        public String getSystemId() {
            Locator l = findLocator();
            if(l!=null)     return l.getSystemId();
            return          null;
        }

    }
}