Startup.java

/*
 * Copyright 2017 OmniFaces
 *
 * 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.omnifaces.cdi;

import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.inject.Stereotype;

/**
 * <p>
 * Stereo type that designates a bean as an eagerly instantiated bean with application scope.
 * Watch out with IDE autocomplete on import that you don't accidentally import EJB's one.
 * <pre>
 * import org.omnifaces.cdi.Startup;
 *
 * @Startup
 * public class MyStartupBean {}
 * </pre>
 * <p>
 * In effect, this annotation does exactly the same as:
 * <pre>
 * import javax.enterprise.context.ApplicationScoped;
 * import org.omnifaces.cdi.Eager;
 *
 * @Eager
 * @ApplicationScoped
 * public class MyStartupBean {}
 * </pre>
 * <p>
 * This bean type effectively functions as a CDI based startup listener for the web application.
 * <p>
 * Note that Java EE thus also provides the <code>javax.ejb.Startup</code> and <code>javax.ejb.Singleton</code>
 * annotations which together provide similar functionality, but it requires an EJB dependency (which may not be
 * applicable on e.g. Tomcat+Weld) and it will result in the bean annotated with these annotations to become an EJB
 * session bean (with automatic transaction management and automatic locking which you might need to turn off with yet
 * more additional <code>javax.ejb.TransactionAttribute</code> and <code>javax.ejb.Lock</code> annotations if these are
 * not appropriate for some situation).
 *
 * @since 1.8
 * @author Arjan Tijms
 *
 */
@Documented
@ApplicationScoped
@Eager
@Stereotype
@Retention(RUNTIME)
@Target(TYPE)
public @interface Startup {
	//
}