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/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * 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.
 */

package com.liferay.osgi.service.tracker.collections.map;

import com.liferay.osgi.service.tracker.collections.ServiceReferenceServiceTuple;

import java.util.HashMap;
import java.util.Map;
import java.util.function.BiFunction;
import java.util.function.Function;

import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTrackerCustomizer;

/**
 * @author Carlos Sierra Andrés
 */
public class ServiceTrackerCustomizerFactory {

	public static  Function>
		createFromFunction(BiFunction, S, T> function) {

		return b -> new ServiceTrackerCustomizer() {

			@Override
			public T addingService(ServiceReference serviceReference) {
				S service = b.getService(serviceReference);

				try {
					return function.apply(serviceReference, service);
				}
				catch (Exception exception) {
					b.ungetService(serviceReference);

					throw exception;
				}
			}

			@Override
			public void modifiedService(
				ServiceReference serviceReference, T t) {

				removedService(serviceReference, t);

				addingService(serviceReference);
			}

			@Override
			public void removedService(
				ServiceReference serviceReference, T t) {

				b.ungetService(serviceReference);
			}

		};
	}

	public static 
		ServiceTrackerCustomizer>
			serviceReferenceServiceTuple(final BundleContext bundleContext) {

		return new ServiceTrackerCustomizer
			>() {

			@Override
			public ServiceReferenceServiceTuple addingService(
				ServiceReference serviceReference) {

				S service = bundleContext.getService(serviceReference);

				if (service == null) {
					return null;
				}

				return new ServiceReferenceServiceTuple<>(
					serviceReference, service);
			}

			@Override
			public void modifiedService(
				ServiceReference serviceReference,
				ServiceReferenceServiceTuple
					serviceReferenceServiceTuple) {
			}

			@Override
			public void removedService(
				ServiceReference serviceReference,
				ServiceReferenceServiceTuple
					serviceReferenceServiceTuple) {

				bundleContext.ungetService(serviceReference);
			}

		};
	}

	public static  ServiceTrackerCustomizer>
		serviceWrapper(BundleContext bundleContext) {

		return new ServiceTrackerCustomizer>() {

			@Override
			public ServiceWrapper addingService(
				ServiceReference serviceReference) {

				S service = bundleContext.getService(serviceReference);

				if (service == null) {
					return null;
				}

				try {
					return new ServiceWrapperImpl<>(serviceReference, service);
				}
				catch (Throwable throwable) {
					bundleContext.ungetService(serviceReference);

					throw throwable;
				}
			}

			@Override
			public void modifiedService(
				ServiceReference serviceReference,
				ServiceWrapper serviceWrapper) {

				ServiceWrapperImpl serviceWrapperImpl =
					(ServiceWrapperImpl)serviceWrapper;

				serviceWrapperImpl._resetProperties();
			}

			@Override
			public void removedService(
				ServiceReference serviceReference,
				ServiceWrapper serviceWrapper) {

				bundleContext.ungetService(serviceReference);
			}

		};
	}

	public interface ServiceWrapper {

		public Map getProperties();

		public S getService();

	}

	private static class ServiceWrapperImpl implements ServiceWrapper {

		@Override
		public Map getProperties() {
			Map properties = _properties;

			if (properties == null) {
				properties = new HashMap<>();

				String[] propertyKeys = _serviceReference.getPropertyKeys();

				for (String propertyKey : propertyKeys) {
					properties.put(
						propertyKey,
						_serviceReference.getProperty(propertyKey));
				}

				_properties = properties;
			}

			return properties;
		}

		@Override
		public S getService() {
			return _service;
		}

		private ServiceWrapperImpl(
			ServiceReference serviceReference, S service) {

			_serviceReference = serviceReference;
			_service = service;
		}

		private void _resetProperties() {
			_properties = null;
		}

		private volatile Map _properties;
		private final S _service;
		private final ServiceReference _serviceReference;

	}

}