/*
 * Copyright (c) OSGi Alliance (2011, 2016). 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.osgi.service.component.annotations;

/**
 * Cardinality for the {@link Reference} annotation.
 * 
 * <p>
 * Specifies if the reference is optional and if the component implementation
 * support a single bound service or multiple bound services.
 * 
 * @author $Id: a1dac9ffbd1c21c4e58d165cc95bd4368da0ec05 $
 */
public enum ReferenceCardinality {
	/**
	 * The reference is optional and unary. That is, the reference has a
	 * cardinality of {@code 0..1}.
	 */
	OPTIONAL("0..1"),

	/**
	 * The reference is mandatory and unary. That is, the reference has a
	 * cardinality of {@code 1..1}.
	 */
	MANDATORY("1..1"),

	/**
	 * The reference is optional and multiple. That is, the reference has a
	 * cardinality of {@code 0..n}.
	 */
	MULTIPLE("0..n"),

	/**
	 * The reference is mandatory and multiple. That is, the reference has a
	 * cardinality of {@code 1..n}.
	 */
	AT_LEAST_ONE("1..n");

	private final String	value;

	ReferenceCardinality(String value) {
		this.value = value;
	}

	@Override
	public String toString() {
		return value;
	}
}
