| /* |
| * 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; |
| |
| /** |
| * An interface to be implemented by objects that can determine the |
| * settings of an {@code IIOParam} 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} 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} method, a controller obtains |
| * initial values by querying the {@code IIOParam} object's |
| * {@code get} methods, modifies values by whatever means, then |
| * invokes the {@code IIOParam} object's {@code set} methods |
| * to modify the appropriate settings. Normally, these |
| * {@code set} methods will be invoked all at once at a final |
| * commit in order that a cancel operation not disturb existing |
| * values. In general, applications may expect that when the |
| * {@code activate} method returns {@code true}, the |
| * {@code IIOParam} object is ready for use in a read or write |
| * operation. |
| * |
| * <p> Vendors may choose to provide GUIs for the |
| * {@code IIOParam} subclasses they define for a particular |
| * plug-in. These can be set up as default controllers in the |
| * corresponding {@code IIOParam} subclasses. |
| * |
| * <p> Applications may override any default GUIs and provide their |
| * own controllers embedded in their own framework. All that is |
| * required is that the {@code activate} method behave modally |
| * (not returning until either cancelled or committed), though it need |
| * not put up an explicitly modal dialog. Such a non-modal GUI |
| * component would be coded roughly as follows: |
| * |
| * <br> |
| * <pre> |
| * class MyGUI extends SomeComponent implements IIOParamController { |
| * |
| * public MyGUI() { |
| * // ... |
| * setEnabled(false); |
| * } |
| * |
| * public boolean activate(IIOParam param) { |
| * // disable other components if desired |
| * setEnabled(true); |
| * // go to sleep until either cancelled or committed |
| * boolean ret = false; |
| * if (!cancelled) { |
| * // set values on param |
| * ret = true; |
| * } |
| * setEnabled(false); |
| * // enable any components disabled above |
| * return ret; |
| * } |
| * </pre> |
| * |
| * <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} method would simply look up or |
| * compute the settings, call the {@code IIOParam.setXXX} |
| * methods, and return {@code true}. |
| * |
| * @see IIOParam#setController |
| * @see IIOParam#getController |
| * @see IIOParam#getDefaultController |
| * @see IIOParam#hasController |
| * @see IIOParam#activateController |
| * |
| */ |
| public interface IIOParamController { |
| |
| /** |
| * Activates the controller. If {@code true} is returned, |
| * all settings in the {@code IIOParam} object should be |
| * ready for use in a read or write operation. If |
| * {@code false} is returned, no settings in the |
| * {@code IIOParam} object will be disturbed (<i>i.e.</i>, |
| * the user canceled the operation). |
| * |
| * @param param the {@code IIOParam} object to be modified. |
| * |
| * @return {@code true} if the {@code IIOParam} has been |
| * modified, {@code false} otherwise. |
| * |
| * @exception IllegalArgumentException if {@code param} is |
| * {@code null} or is not an instance of the correct class. |
| */ |
| boolean activate(IIOParam param); |
| } |