org.ldp4j.application.kernel.lifecycle.DefaultLifecycleEnvironment.java Source code

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Here is the source code for org.ldp4j.application.kernel.lifecycle.DefaultLifecycleEnvironment.java

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/**
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   This file is part of the LDP4j Project:
 *     http://www.ldp4j.org/
 *
 *   Center for Open Middleware
 *     http://www.centeropenmiddleware.com/
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   Copyright (C) 2014-2016 Center for Open Middleware.
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   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.
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   Artifact    : org.ldp4j.framework:ldp4j-application-kernel-core:0.2.1
 *   Bundle      : ldp4j-application-kernel-core-0.2.1.jar
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 */
package org.ldp4j.application.kernel.lifecycle;

import static com.google.common.base.Preconditions.checkNotNull;

import java.util.Iterator;
import java.util.LinkedList;

import org.ldp4j.application.ApplicationContext;
import org.ldp4j.application.engine.ApplicationContextBootstrapException;
import org.ldp4j.application.lifecycle.ApplicationLifecycleListener;
import org.ldp4j.application.lifecycle.LifecycleEnvironment;
import org.ldp4j.application.lifecycle.Managed;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Lists;

final class DefaultLifecycleEnvironment implements LifecycleEnvironment {

    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultLifecycleEnvironment.class);

    private final LinkedList<Managed> managedObjects; // NOSONAR
    private final LinkedList<ApplicationLifecycleListener> listeners; // NOSONAR

    DefaultLifecycleEnvironment() {
        this.managedObjects = Lists.newLinkedList();
        this.listeners = Lists.newLinkedList();
    }

    @Override
    public void register(Managed managed) {
        checkNotNull(managed, "Managed objects cannot be null");
        this.managedObjects.add(managed);
        LOGGER.debug("Registered managed object {}", managed);
    }

    @Override
    public void addApplicationLifecycleListener(ApplicationLifecycleListener listener) {
        checkNotNull(listener, "Application lifecycle listeners cannot be null");
        this.listeners.add(listener);
        LOGGER.debug("Registered application lifecycle listener {}", listener);
    }

    void start(ApplicationContext context) throws ApplicationContextBootstrapException {
        LOGGER.info("Starting application components...");
        LOGGER.debug("Starting managed objects...");
        for (Managed managed : this.managedObjects) {
            try {
                managed.start();
                LOGGER.trace("Started managed object {}.", managed);
            } catch (Exception e) {
                LOGGER.warn("Could not start managed object {}", managed, e);
                throw new ApplicationContextBootstrapException("Could not start managed object " + managed, e);
            }
        }
        LOGGER.debug("Notifying start-up event to application lifecycle listeners...");
        for (ApplicationLifecycleListener listener : this.listeners) {
            try {
                listener.applicationStarted(context);
                LOGGER.trace("Notified start-up to {}.", listener);
            } catch (Exception e) {
                LOGGER.warn("Listener {} failed when notifying startup", listener, e);
                throw new ApplicationContextBootstrapException(
                        "Listeners " + listener + " failed when notifying startup", e);
            }
        }
        LOGGER.info("Application components started.");
    }

    void stop() {
        LOGGER.info("Stopping application components...");
        LOGGER.debug("Stopping managed objects...");
        Iterator<Managed> iterator = this.managedObjects.descendingIterator();
        while (iterator.hasNext()) {
            Managed managed = iterator.next();
            try {
                managed.stop();
                LOGGER.trace("Stopped managed object {}.", managed);
            } catch (Exception e) {
                LOGGER.warn("Could not stop managed object {}", managed, e);
            }
        }
        LOGGER.debug("Notifying stop event to application lifecycle listeners...");
        for (ApplicationLifecycleListener listener : this.listeners) {
            try {
                listener.applicationStopped();
                LOGGER.trace("Notified stop to {}.", listener);
            } catch (Exception e) {
                LOGGER.warn("Listener {} failed when notifying stop", listener, e);
            }
        }
        LOGGER.info("Application components stopped.");
    }

}