001/*
002 * (C) Copyright 2006-2012 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     IBM Corporation - initial API and implementation
018 *     Nuxeo - added generics in method signatures
019 */
020package org.nuxeo.runtime.model;
021
022/**
023 * An interface for an adaptable object.
024 * <p>
025 * Adaptable objects can be dynamically extended to provide different interfaces (or "adapters"). Adapters are created
026 * by adapter factories, which are in turn managed by type by adapter managers.
027 * <p>
028 * For example,
029 *
030 * <pre>
031 *     IAdaptable a = [some adaptable];
032 *     IFoo x = a.getAdapter(IFoo.class);
033 *     if (x != null)
034 *         [do IFoo things with x]
035 * </pre>
036 * <p>
037 * This interface can be used without OSGi running.
038 * <p>
039 * Clients may implement this interface, or obtain a default implementation of this interface by subclassing
040 * <code>PlatformObject</code>.
041 *
042 * @see AdapterFactory
043 * @see AdapterManager
044 * @see AdaptableObject
045 */
046public interface Adaptable {
047
048    /**
049     * Returns an object which is an instance of the given class associated with this object. Returns <code>null</code>
050     * if no such object can be found.
051     *
052     * @param adapter the adapter class to look up
053     * @return a object castable to the given class, or <code>null</code> if this object does not have an adapter for
054     *         the given class
055     */
056    <T> T getAdapter(Class<T> adapter);
057
058}