/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file to you 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.felix.dm;

/**
 * Configuration dependency that can track the availability of a (valid) configuration. To use
 * it, specify a PID for the configuration. The dependency is always required, because if it is
 * not, it does not make sense to use the dependency manager. In that scenario, simply register
 * your component as a <code>ManagedService(Factory)</code> and handle everything yourself. Also,
 * only managed services are supported, not factories. There are a couple of things you need to
 * be aware of when implementing the <code>updated(Dictionary)</code> method:
 * <ul>
 * <li>Make sure it throws a <code>ConfigurationException</code> when you get a configuration
 * that is invalid. In this case, the dependency will not change: if it was not available, it
 * will still not be. If it was available, it will remain available and implicitly assume you
 * keep working with your old configuration.</li>
 * <li>This method will be called before all required dependencies are available. Make sure you
 * do not depend on these to parse your settings.</li>
 * </ul>
 * 
 * @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
 */
public interface ConfigurationDependency extends Dependency, ComponentDependencyDeclaration {
	/**
	 * Sets the name of the callback method that should be invoked when a configuration
	 * is available. The contract for this method is identical to that of
	 * <code>ManagedService.updated(Dictionary) throws ConfigurationException</code>.
	 * 
	 * @param callback the name of the callback method
	 */
	ConfigurationDependency setCallback(String callback);

	/**
	 * Sets the <code>service.pid</code> of the configuration you are depending
	 * on.
	 */
	ConfigurationDependency setPid(String pid);

	/**
	 * Sets propagation of the configuration properties to the service
	 * properties. Any additional service properties specified directly are
	 * merged with these.
	 */
	ConfigurationDependency setPropagate(boolean propagate);

	/**
	 * The label used to display the tab name (or section) where the properties
	 * are displayed. Example: "Printer Service".
	 * 
	 * @return The label used to display the tab name where the properties are
	 *         displayed (may be localized)
	 */
	ConfigurationDependency setHeading(String heading);

	/**
	 * A human readable description of the PID this configuration is associated
	 * with. Example: "Configuration for the PrinterService bundle".
	 * 
	 * @return A human readable description of the PID this configuration is
	 *         associated with (may be localized)
	 */
	ConfigurationDependency setDescription(String description);

	/**
	 * Points to the basename of the Properties file that can localize the Meta
	 * Type informations. The default localization base name for the properties
	 * is OSGI-INF/l10n/bundle, but can be overridden by the manifest
	 * Bundle-Localization header (see core specification, in section
	 * Localization on page 68). You can specify a specific localization
	 * basename file using this method (e.g.
	 * <code>setLocalization("person")</code> will match person_du_NL.properties
	 * in the root bundle directory.
	 */
	ConfigurationDependency setLocalization(String path);

	/**
	 * Adds a MetaData regarding a given configuration property.
	 */
	ConfigurationDependency add(PropertyMetaData properties);

	/**
	 * Sets this dependency to be instance bound or not.
	 * 
	 * @param isInstanceBound <code>true</code> if this dependency should be instance bound
	 */
	ConfigurationDependency setInstanceBound(boolean isInstanceBound);
}