/*
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.tools.internal.xjc;

//import java.lang.reflect.Field;
//import java.lang.reflect.Method;
import java.net.URL;

import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.ValidatorHandler;

import com.sun.xml.internal.bind.v2.WellKnownNamespace;

import org.xml.sax.SAXException;

/**
 * Wraps a JAXP {@link Schema} object and lazily instantiate it.
 *
 * This object is thread-safe. There should be only one instance of
 * this for the whole VM.
 *
 * @author Kohsuke Kawaguchi
 */
public final class SchemaCache {

    private Schema schema;

    private final URL source;

    public SchemaCache(URL source) {
        this.source = source;
    }

    public ValidatorHandler newValidator() {
        synchronized(this) {
            if(schema==null) {
                try {
                    schema = SchemaFactory.newInstance(WellKnownNamespace.XML_SCHEMA).newSchema(source);
                } catch (SAXException e) {
                    // we make sure that the schema is correct before we ship.
                    throw new AssertionError(e);
                }
            }
        }

        ValidatorHandler handler = schema.newValidatorHandler();
//        fixValidatorBug6246922(handler);

        return handler;
    }


    /**
     * Fix the bug 6246922 if we are running inside Tiger.
     */
//    private void fixValidatorBug6246922(ValidatorHandler handler) {
//        try {
//            Field f = handler.getClass().getDeclaredField("errorReporter");
//            f.setAccessible(true);
//            Object errorReporter = f.get(handler);
//
//            Method get = errorReporter.getClass().getDeclaredMethod("getMessageFormatter",String.class);
//            Object currentFormatter = get.invoke(errorReporter,"http://www.w3.org/TR/xml-schema-1");
//            if(currentFormatter!=null)
//                return;
//
//            // otherwise attempt to set
//            Method put = null;
//            for( Method m : errorReporter.getClass().getDeclaredMethods() ) {
//                if(m.getName().equals("putMessageFormatter")) {
//                    put = m;
//                    break;
//                }
//            }
//            if(put==null)       return; // unable to find the putMessageFormatter
//
//            ClassLoader cl = errorReporter.getClass().getClassLoader();
//            String className = "com.sun.org.apache.xerces.internal.impl.xs.XSMessageFormatter";
//            Class xsformatter;
//            if(cl==null) {
//                xsformatter = Class.forName(className);
//            } else {
//                xsformatter = cl.loadClass(className);
//            }
//
//            put.invoke(errorReporter,"http://www.w3.org/TR/xml-schema-1",xsformatter.newInstance());
//        } catch( Throwable t ) {
//            // this code is heavily relying on an implementation detail of JAXP RI,
//            // so any error is likely because of the incompatible change in it.
//            // don't die if that happens. Just continue. The worst case is a illegible
//            // error messages, which are much better than not compiling schemas at all.
//        }
//    }
}