1 /* 2 * Copyright (c) 2000, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.imageio.metadata; 27 28 /** 29 * An interface to be implemented by objects that can determine the 30 * settings of an <code>IIOMetadata</code> object, either by putting 31 * up a GUI to obtain values from a user, or by other means. This 32 * interface merely specifies a generic <code>activate</code> method 33 * that invokes the controller, without regard for how the controller 34 * obtains values (<i>i.e.</i>, whether the controller puts up a GUI 35 * or merely computes a set of values is irrelevant to this 36 * interface). 37 * 38 * <p> Within the <code>activate</code> method, a controller obtains 39 * initial values by querying the <code>IIOMetadata</code> object's 40 * settings, either using the XML DOM tree or a plug-in specific 41 * interface, modifies values by whatever means, then modifies the 42 * <code>IIOMetadata</code> object's settings, using either the 43 * <code>setFromTree</code> or <code>mergeTree</code> methods, or a 44 * plug-in specific interface. In general, applications may expect 45 * that when the <code>activate</code> method returns 46 * <code>true</code>, the <code>IIOMetadata</code> object is ready for 47 * use in a write operation. 48 * 49 * <p> Vendors may choose to provide GUIs for the 50 * <code>IIOMetadata</code> subclasses they define for a particular 51 * plug-in. These can be set up as default controllers in the 52 * corresponding <code>IIOMetadata</code> subclasses. 53 * 54 * <p> Alternatively, an algorithmic process such as a database lookup 55 * or the parsing of a command line could be used as a controller, in 56 * which case the <code>activate</code> method would simply look up or 57 * compute the settings, call methods on <code>IIOMetadata</code> to 58 * set its state, and return <code>true</code>. 59 * 60 * @see IIOMetadata#setController 61 * @see IIOMetadata#getController 62 * @see IIOMetadata#getDefaultController 63 * @see IIOMetadata#hasController 64 * @see IIOMetadata#activateController 65 * 66 */ 67 public interface IIOMetadataController { 68 69 /** 70 * Activates the controller. If <code>true</code> is returned, 71 * all settings in the <code>IIOMetadata</code> object should be 72 * ready for use in a write operation. If <code>false</code> is 73 * returned, no settings in the <code>IIOMetadata</code> object 74 * will be disturbed (<i>i.e.</i>, the user canceled the 75 * operation). 76 * 77 * @param metadata the <code>IIOMetadata</code> object to be modified. 78 * 79 * @return <code>true</code> if the <code>IIOMetadata</code> has been 80 * modified, <code>false</code> otherwise. 81 * 82 * @exception IllegalArgumentException if <code>metadata</code> is 83 * <code>null</code> or is not an instance of the correct class. 84 */ 85 boolean activate(IIOMetadata metadata); 86 }