/*
 * Copyright (c) 2013, grossmann
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the name of the jo-widgets.org nor the
 *   names of its contributors may be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL jo-widgets.org BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

package org.jowidgets.beanvalidation.bootstrap.api;

import java.util.Iterator;
import java.util.ServiceLoader;

import javax.validation.Validation;
import javax.validation.ValidationException;
import javax.validation.Validator;

import org.jowidgets.classloading.api.SharedClassLoader;
import org.jowidgets.logging.api.ILogger;
import org.jowidgets.logging.api.LoggerProvider;
import org.jowidgets.util.Assert;

public final class BeanValidatorFactory {

    private static final ILogger LOGGER = LoggerProvider.get(BeanValidatorFactory.class);

    private static IBeanValidatorFactory instance = createDefaultFactory();

    private BeanValidatorFactory() {}

    private static IBeanValidatorFactory createDefaultFactory() {
        IBeanValidatorFactory result = null;
        final ServiceLoader<IBeanValidatorFactory> serviceLoader = ServiceLoader.load(
                IBeanValidatorFactory.class,
                SharedClassLoader.getCompositeClassLoader());

        final Iterator<IBeanValidatorFactory> services = serviceLoader.iterator();
        if (services.hasNext()) {
            result = services.next();
        }
        if (result == null) {
            result = new DefaultBeanValidatorFactory();
        }
        return result;
    }

    public static IBeanValidatorFactory getInstance() {
        return instance;
    }

    public static synchronized void setFactory(final IBeanValidatorFactory factory) {
        Assert.paramNotNull(factory, "factory");
        instance = factory;
    }

    public static Validator create() {
        return getInstance().create();
    }

    private static class DefaultBeanValidatorFactory implements IBeanValidatorFactory {

        private boolean failed;

        @Override
        public Validator create() {
            if (failed) {
                return null;
            }
            else {
                try {
                    return Validation.buildDefaultValidatorFactory().getValidator();
                }
                catch (final ValidationException e) {
                    LOGGER.info("No implementaion for javax.validation (bean balidation) found "
                        + Validator.class.getName()
                        + ". Bean validation anotations will have no effect!", e);
                    failed = true;
                    return null;
                }
            }
        }
    }

}