J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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 | } |