/* * Copyright (c) 2000, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.imageio.metadata; /** * An interface to be implemented by objects that can determine the * settings of an <code>IIOMetadata</code> object, either by putting * up a GUI to obtain values from a user, or by other means.  This * interface merely specifies a generic <code>activate</code> method * that invokes the controller, without regard for how the controller * obtains values (<i>i.e.</i>, whether the controller puts up a GUI * or merely computes a set of values is irrelevant to this * interface). * * <p> Within the <code>activate</code> method, a controller obtains * initial values by querying the <code>IIOMetadata</code> object's * settings, either using the XML DOM tree or a plug-in specific * interface, modifies values by whatever means, then modifies the * <code>IIOMetadata</code> object's settings, using either the * <code>setFromTree</code> or <code>mergeTree</code> methods, or a * plug-in specific interface.  In general, applications may expect * that when the <code>activate</code> method returns * <code>true</code>, the <code>IIOMetadata</code> object is ready for * use in a write operation. * * <p> Vendors may choose to provide GUIs for the * <code>IIOMetadata</code> subclasses they define for a particular * plug-in.  These can be set up as default controllers in the * corresponding <code>IIOMetadata</code> subclasses. * * <p> Alternatively, an algorithmic process such as a database lookup * or the parsing of a command line could be used as a controller, in * which case the <code>activate</code> method would simply look up or * compute the settings, call methods on <code>IIOMetadata</code> to * set its state, and return <code>true</code>. * * @see IIOMetadata#setController * @see IIOMetadata#getController * @see IIOMetadata#getDefaultController * @see IIOMetadata#hasController * @see IIOMetadata#activateController * */public interface IIOMetadataController {     /**     * Activates the controller.  If <code>true</code> is returned,     * all settings in the <code>IIOMetadata</code> object should be     * ready for use in a write operation.  If <code>false</code> is     * returned, no settings in the <code>IIOMetadata</code> object     * will be disturbed (<i>i.e.</i>, the user canceled the     * operation).     *     * @param metadata the <code>IIOMetadata</code> object to be modified.     *     * @return <code>true</code> if the <code>IIOMetadata</code> has been     * modified, <code>false</code> otherwise.     *     * @exception IllegalArgumentException if <code>metadata</code> is     * <code>null</code> or is not an instance of the correct class.     */    boolean activate(IIOMetadata metadata);}