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| 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; | |
| 27 | + | |
| 28 | +/** | |
| 29 | + * An interface to be implemented by objects that can determine the | |
| 30 | + * settings of an <code>IIOParam</code> object, either by putting up a | |
| 31 | + * 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>IIOParam</code> object's | |
| 40 | + * <code>get</code> methods, modifies values by whatever means, then | |
| 41 | + * invokes the <code>IIOParam</code> object's <code>set</code> methods | |
| 42 | + * to modify the appropriate settings. Normally, these | |
| 43 | + * <code>set</code> methods will be invoked all at once at a final | |
| 44 | + * commit in order that a cancel operation not disturb existing | |
| 45 | + * values. In general, applications may expect that when the | |
| 46 | + * <code>activate</code> method returns <code>true</code>, the | |
| 47 | + * <code>IIOParam</code> object is ready for use in a read or write | |
| 48 | + * operation. | |
| 49 | + * | |
| 50 | + * <p> Vendors may choose to provide GUIs for the | |
| 51 | + * <code>IIOParam</code> subclasses they define for a particular | |
| 52 | + * plug-in. These can be set up as default controllers in the | |
| 53 | + * corresponding <code>IIOParam</code> subclasses. | |
| 54 | + * | |
| 55 | + * <p> Applications may override any default GUIs and provide their | |
| 56 | + * own controllers embedded in their own framework. All that is | |
| 57 | + * required is that the<code>activate</code> method behave modally | |
| 58 | + * (not returning until either cancelled or committed), though it need | |
| 59 | + * not put up an explicitly modal dialog. Such a non-modal GUI | |
| 60 | + * component would be coded roughly as follows: | |
| 61 | + * | |
| 62 | + * <br> | |
| 63 | + * <pre> | |
| 64 | + * class MyGUI extends SomeComponent implements IIOParamController { | |
| 65 | + * | |
| 66 | + * public MyGUI() { | |
| 67 | + * // ... | |
| 68 | + * setEnabled(false); | |
| 69 | + * } | |
| 70 | + * | |
| 71 | + * public boolean activate(IIOParam param) { | |
| 72 | + * // disable other components if desired | |
| 73 | + * setEnabled(true); | |
| 74 | + * // go to sleep until either cancelled or committed | |
| 75 | + * boolean ret = false; | |
| 76 | + * if (!cancelled) { | |
| 77 | + * // set values on param | |
| 78 | + * ret = true; | |
| 79 | + * } | |
| 80 | + * setEnabled(false); | |
| 81 | + * // enable any components disabled above | |
| 82 | + * return ret; | |
| 83 | + * } | |
| 84 | + * </pre> | |
| 85 | + * | |
| 86 | + * <p> Alternatively, an algorithmic process such as a database lookup | |
| 87 | + * or the parsing of a command line could be used as a controller, in | |
| 88 | + * which case the <code>activate</code> method would simply look up or | |
| 89 | + * compute the settings, call the <code>IIOParam.setXXX</code> | |
| 90 | + * methods, and return <code>true</code>. | |
| 91 | + * | |
| 92 | + * @see IIOParam#setController | |
| 93 | + * @see IIOParam#getController | |
| 94 | + * @see IIOParam#getDefaultController | |
| 95 | + * @see IIOParam#hasController | |
| 96 | + * @see IIOParam#activateController | |
| 97 | + * | |
| 98 | + */ | |
| 99 | +public interface IIOParamController { | |
| 100 | + | |
| 101 | + /** | |
| 102 | + * Activates the controller. If <code>true</code> is returned, | |
| 103 | + * all settings in the <code>IIOParam</code> object should be | |
| 104 | + * ready for use in a read or write operation. If | |
| 105 | + * <code>false</code> is returned, no settings in the | |
| 106 | + * <code>IIOParam</code> object will be disturbed (<i>i.e.</i>, | |
| 107 | + * the user canceled the operation). | |
| 108 | + * | |
| 109 | + * @param param the <code>IIOParam</code> object to be modified. | |
| 110 | + * | |
| 111 | + * @return <code>true</code> if the <code>IIOParam</code> has been | |
| 112 | + * modified, <code>false</code> otherwise. | |
| 113 | + * | |
| 114 | + * @exception IllegalArgumentException if <code>param</code> is | |
| 115 | + * <code>null</code> or is not an instance of the correct class. | |
| 116 | + */ | |
| 117 | + boolean activate(IIOParam param); | |
| 118 | +} | |