org.eiichiro.gig.GigListener.java Source code

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Here is the source code for org.eiichiro.gig.GigListener.java

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/*
 * Copyright (C) 2011 Eiichiro Uchiumi. All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 *     
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.eiichiro.gig;

import static org.eiichiro.gig.Version.*;
import java.lang.reflect.Modifier;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;

import org.eiichiro.jaguar.Jaguar;
import org.eiichiro.jaguar.WebListener;
import org.eiichiro.reverb.lang.UncheckedException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Predicate;
import com.google.common.collect.Sets;

/**
 * {@code GigListener} is a {@code WebListener} extension to bootstrap/shutdown 
 * Gig application.
 * 
 * @author <a href="mailto:eiichiro@eiichiro.org">Eiichiro Uchiumi</a>
 */
public class GigListener extends WebListener {

    public static final String CONFIGURATION = "org.eiichiro.gig.configuration";

    private Logger logger = LoggerFactory.getLogger(getClass());

    private Configuration configuration;

    static {
        Logger logger = LoggerFactory.getLogger(Version.class);
        logger.info("Gig " + MAJOR + "." + MINER + "." + BUILD);
        //      logger.info("Copyright (C) 2011 Eiichiro Uchiumi. All Rights Reserved.");
    }

    /**
     * Loads the {@link Configuration} specified by the deployment descriptor and 
     * sets it to the {@code ServletContext}.
     * If no {@code Configuration} is specified, this method uses 
     * {@link DefaultConfiguration}.
     * 
     * @param sce {@code ServletContextEvent}.
     */
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        String clazz = sce.getServletContext().getInitParameter(CONFIGURATION);
        Configuration configuration = null;

        if (clazz == null) {
            configuration = new DefaultConfiguration();
        } else {
            try {
                configuration = (Configuration) Class.forName(clazz).newInstance();
            } catch (Exception e) {
                logger.error("Failed to load configuration", e);
                throw new UncheckedException(e);
            }
        }

        sce.getServletContext().setAttribute(CONFIGURATION, configuration);
        this.configuration = configuration;
        super.contextInitialized(sce);
    }

    /**
     * Returns the deployment qualifier from the {@code Configuration} loaded.
     * 
     * @param context {@code ServletContext}.
     * @return The deployment qualifier from the {@code Configuration} loaded.
     */
    @Override
    protected Class<?> deployment(ServletContext context) {
        return configuration.deployment();
    }

    /**
     * Installs service component classes to the Jaguar container from the 
     * {@link Module} which the {@code Configuration#module()} returns.
     * 
     * @param context {@code ServletContext}.
     */
    @Override
    protected void install(ServletContext context) {
        Jaguar.install(Sets.filter(configuration.module().components(), new Predicate<Class<?>>() {

            @Override
            public boolean apply(Class<?> clazz) {
                return (!clazz.isInterface() && !Modifier.isAbstract(clazz.getModifiers()));
            }

        }));
    }

}