Adaptable.java

/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Nuxeo - added generics in method signatures
 *******************************************************************************/
package org.eclipse.ecr.runtime.model;


/**
 * An interface for an adaptable object.
 * <p>
 * Adaptable objects can be dynamically extended to provide different
 * interfaces (or "adapters").  Adapters are created by adapter
 * factories, which are in turn managed by type by adapter managers.
 * <p>
 * For example,
 * <pre>
 *     IAdaptable a = [some adaptable];
 *     IFoo x = a.getAdapter(IFoo.class);
 *     if (x != null)
 *         [do IFoo things with x]
 * </pre>
 * <p>
 * This interface can be used without OSGi running.
 * <p>
 * Clients may implement this interface, or obtain a default implementation
 * of this interface by subclassing <code>PlatformObject</code>.
 *
 * @see AdapterFactory
 * @see AdapterManager
 * @see AdaptableObject
 */
public interface Adaptable {

    /**
     * Returns an object which is an instance of the given class
     * associated with this object. Returns <code>null</code> if
     * no such object can be found.
     *
     * @param adapter the adapter class to look up
     * @return a object castable to the given class,
     *    or <code>null</code> if this object does not
     *    have an adapter for the given class
     */
    <T> T getAdapter(Class<T> adapter);

}