core/api/src/main/java/org/apache/zest/api/service/ServiceReference.java

/*
 * Copyright (c) 2008, Rickard Öberg. 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.apache.zest.api.service;

import org.apache.zest.api.activation.ActivationEventListenerRegistration;
import org.apache.zest.api.structure.MetaInfoHolder;
import org.apache.zest.api.type.HasTypes;

/**
 * From a ServiceReference you can access and modify metadata about a service.
 * You can also access the actual service through get(), that can then be invoked.
 */
public interface ServiceReference<T>
    extends HasTypes, ActivationEventListenerRegistration, MetaInfoHolder
{
    /**
     * @return the service's identity
     */
    String identity();

    /**
     * @return the actual service
     */
    T get();

    /**
     * @return TRUE if the service is active, otherwise return FALSE
     */
    boolean isActive();

    /**
     * @return TRUE if the service is available, otherwise return FALSE
     */
    boolean isAvailable();
}