/*
 * @(#)$Id: DocumentBuilderImpl.java,v 1.1 2001/10/01 19:29:20 Bear Exp $
 *
 * Copyright 2001 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */
package com.sun.msv.verifier.jaxp;

import java.io.File;
import java.io.InputStream;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
//import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.iso_relax.verifier.Verifier;
//import org.iso_relax.verifier.VerifierConfigurationException;
import org.iso_relax.verifier.Schema;
import com.sun.msv.verifier.jarv.TheFactoryImpl;

/**
 * DocumentBuilder implementation that supports validation.
 * 
 * <p>
 * This class uses another DocumentBuilder implementation and 
 * adds the validation capability to it.
 * 
 * @author <a href="mailto:kohsuke.kawaguchi@sun.com">Kohsuke KAWAGUCHI</a>
 */
class DocumentBuilderImpl extends DocumentBuilder
{
	/**
	 * Wrapped DocumentBuilder that does everything else.
	 */
	private final DocumentBuilder core;

	/**
	 * The validation will be performed using this verifier.
	 */
	private final Verifier verifier;
	
	DocumentBuilderImpl( DocumentBuilder _core, Schema _schema ) throws ParserConfigurationException {
		this.core = _core;
		try {
			verifier = _schema.newVerifier();
		} catch( Exception e ) {
			// this will not happen with our implementation of JARV.
			throw new ParserConfigurationException(e.toString());
		}
		// set an error handler to throw an exception in case of error.
		verifier.setErrorHandler( com.sun.msv.verifier.util.ErrorHandlerImpl.theInstance );
	}
	
	
	public DOMImplementation getDOMImplementation() {
		return core.getDOMImplementation();
	}
	
	public boolean isNamespaceAware() {
		return core.isNamespaceAware();
	}
	
	public boolean isValidating() {
		return true;
	}
	
	public Document newDocument() {
		return core.newDocument();
	}
	
	public Document parse( InputSource is ) throws SAXException, IOException {
		return verify(core.parse(is));
	}
	
	public Document parse( File f ) throws SAXException, IOException {
		return verify(core.parse(f));
	}
	
	public Document parse( InputStream is ) throws SAXException, IOException {
		return verify(core.parse(is));
	}
	
	public Document parse( InputStream is, String systemId ) throws SAXException, IOException {
		return verify(core.parse(is,systemId));
	}
	
	public Document parse( String url ) throws SAXException, IOException {
		return verify(core.parse(url));
	}
	
	public void setEntityResolver( EntityResolver resolver ) {
		verifier.setEntityResolver(resolver);
		core.setEntityResolver(resolver);
	}
	
	public void setErrorHandler( ErrorHandler handler ) {
		verifier.setErrorHandler(handler);
		core.setErrorHandler(handler);
	}
	
	
	
	
	/**
	 * Validates a given DOM and returns it if it is valid. Otherwise throw an exception.
	 */
	private Document verify( Document dom ) throws SAXException, IOException {
		if(verifier.verify(dom))
			return dom;	// the document is valid
		
		// this is strange because if any error happens, the error handler
		// will throw an exception.
		throw new SAXException("the document is invalid");
	}
}