/*
 * Copyright 2007 the original author or authors.
 * 
 * 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.wamblee.system.core;

/**
 * A component represents a part of a system that requires a 
 * number of interfaces and provides a number of interfaces. 
 *
 * @author Erik Brakkee
 */
public interface Component {
	
	enum Status { 
		NOT_STARTED, RUNNING, STOPPED
	}
	
	/**
	 * Gets the status of the component. 
	 * @return Status. 
	 */
	Status getStatus();
	
	/**
	 * Gets the name of the subsystem.
	 * @return Subsystem name. 
	 */
	String getName();
	
	/**
	 * Prepends the context with a super context. 
	 */
	void addContext(String aContext);
	
	/**
	 * Gets the fully qualified name of the component which includes
	 * the context of the component.  
	 * This method can only be used after the component has started.
	 * @return Qualified name. 
	 */
	String getQualifiedName(); 

	/**
	 * Gets a description of the provided interfaces. 
	 * @return Provided interfaces. 
	 */
	ProvidedInterface[] getProvidedInterfaces();
	
	/**
	 * Gets a description of the required interfaces. 
	 * @return Required interfaces. 
	 */
	RequiredInterface[] getRequiredInterfaces();

	
	/**
	 * Initialises the subsytem by starting all the services that
	 * it described as provided. 
	 */
	void start();
	
	/**
	 * Gets the list of running services in the subsystem. 
	 * 
	 * This method may only be called after the
	 * {@link #initialize(String, Service[])} has been called. 
	 * @return
	 */
	ProvidedInterface[] getRunningInterfaces();
	
	/**
	 * Stops a subsystem. 
	 */
	void stop(); 
}