org.milyn.rules.RulesProviderFactory Maven / Gradle / Ivy

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/*
 * Milyn - Copyright (C) 2006 - 2010
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License (version 2.1) as published
 * by the Free Software Foundation.
 *
 * This library 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 Lesser General Public License for more details:
 * http://www.gnu.org/licenses/lgpl.txt
 */

package org.milyn.rules;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.milyn.SmooksException;
import org.milyn.cdr.SmooksConfigurationException;
import org.milyn.cdr.annotation.AppContext;
import org.milyn.cdr.annotation.ConfigParam;
import org.milyn.cdr.annotation.ConfigParam.Use;
import org.milyn.container.ApplicationContext;
import org.milyn.delivery.ContentHandler;
import org.milyn.delivery.annotation.Initialize;

/**
 * RulesProviderFactory is responsible for creating {@link RuleProvider}s
 * and installing those providers in the Smooks {@link ApplicationContext}.
 *
 *
 * @author Daniel Bevenius
 */
public final class RulesProviderFactory implements ContentHandler
{
    /**
     * Logger.
     */
    private static Log logger = LogFactory.getLog(RulesProviderFactory.class);

    /**
     * The Smooks {@link ApplicationContext}.
     */
    @AppContext
    private ApplicationContext applicationContext;

    /**
     * The rule name to be used.
     */
    @ConfigParam(use = Use.REQUIRED )
    private String name;

    /**
     * The {@link RuleProvider} implementation to be used.
     */
    @ConfigParam(name = "provider", use = Use.REQUIRED)
    private Class provider;

    /**
     * The source of the rule. Is implementation dependent, may be a file for example.
     */
    @ConfigParam(use = Use.OPTIONAL)
    private String src;

    /**
     * Creates and installs the configured rule provider.
     *
     * @throws SmooksConfigurationException smooks configuration error
     */
    @Initialize
    public void installRuleProvider() throws SmooksConfigurationException
    {
        logger.debug(this);
        if(RuleProvider.class.isAssignableFrom(provider))
        {
            final RuleProvider providerImpl = createProvider(provider);
            providerImpl.setName(name);
            providerImpl.setSrc(src);

            RuleProviderAccessor.add(applicationContext, providerImpl);
        }
        else
        {
            throw new SmooksConfigurationException("Invalid rule provider configuration :'" + this + "'");
        }
    }

    RuleProvider createProvider(final Class providerClass) throws SmooksException
    {
        try
        {
            return providerClass.newInstance();
        }
        catch (final InstantiationException e)
        {
            throw new SmooksException(e.getMessage(), e);
        }
        catch (final IllegalAccessException e)
        {
            throw new SmooksException(e.getMessage(), e);
        }
    }

    @Override
    public String toString()
    {
        return String.format("%s [name=%s, src=%s, provider=%s]", getClass().getSimpleName(), name, src, provider);
    }

}