/*
 *  Copyright 2015 Adobe Systems Incorporated
 *
 *  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 com.adobe.aem.guides.wknd.core.listeners;

import org.apache.sling.api.SlingConstants;
import org.osgi.framework.Constants;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventConstants;
import org.osgi.service.event.EventHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A service to demonstrate how changes in the resource tree
 * can be listened for. It registers an event handler service.
 * The component is activated immediately after the bundle is
 * started through the immediate flag.
 * Please note, that apart from EventHandler services,
 * the immediate flag should not be set on a service.
 */
@Component(service = EventHandler.class,
           immediate = true,
           property = {
                   Constants.SERVICE_DESCRIPTION + "=Demo to listen on changes in the resource tree",
                   EventConstants.EVENT_TOPIC + "=org/apache/sling/api/resource/Resource/*"
           })
public class SimpleResourceListener implements EventHandler {

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

    public void handleEvent(final Event event) {
        logger.debug("Resource event: {} at: {}", event.getTopic(), event.getProperty(SlingConstants.PROPERTY_PATH));
    }
}

