001/*
002 * IzPack - Copyright 2001-2005 Julien Ponge, All Rights Reserved.
003 * 
004 * http://www.izforge.com/izpack/
005 * http://developer.berlios.de/projects/izpack/
006 * 
007 * Copyright 2003 Tino Schwarze
008 * 
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 * 
013 *     http://www.apache.org/licenses/LICENSE-2.0
014 *     
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 */
021
022package com.izforge.izpack.util;
023
024/**
025 * This interface describes basic functionality neccessary for user interaction.
026 * 
027 * All methods or functions which perform work and need to notify or ask the user use a listener for
028 * such purposes. This way, we can separate UI from function.
029 * 
030 */
031
032public interface AbstractUIHandler
033{
034
035    /**
036     * Notify the user about something.
037     * 
038     * The difference between notification and warning is that a notification should not need user
039     * interaction and can savely be ignored.
040     * 
041     * @param message The notification.
042     */
043    public void emitNotification(String message);
044
045    /**
046     * Warn the user about something.
047     * 
048     * @param title The message title (used for dialog name, might not be displayed)
049     * @param message The warning message.
050     * @return true if the user decided not to continue
051     */
052    public boolean emitWarning(String title, String message);
053
054    /**
055     * Notify the user of some error.
056     * 
057     * @param title The message title (used for dialog name, might not be displayed)
058     * @param message The error message.
059     */
060    public void emitError(String title, String message);
061
062    // constants for asking questions
063    // must all be >= 0!
064    public static final int ANSWER_CANCEL = 45;
065
066    public static final int ANSWER_YES = 47;
067
068    public static final int ANSWER_NO = 49;
069
070    // values for choices to present to the user
071    public static final int CHOICES_YES_NO = 37;
072
073    public static final int CHOICES_YES_NO_CANCEL = 38;
074
075    /**
076     * Ask the user a question.
077     * 
078     * @param title The title of the question (useful for dialogs). Might be null.
079     * @param question The question.
080     * @param choices The set of choices to present. Either CHOICES_YES_NO or CHOICES_YES_NO_CANCEL
081     * 
082     * @return The user's choice. (ANSWER_CANCEL, ANSWER_YES or ANSWER_NO)
083     */
084    public int askQuestion(String title, String question, int choices);
085
086    /**
087     * Ask the user a question.
088     * 
089     * @param title The title of the question (useful for dialogs). Might be null.
090     * @param question The question.
091     * @param choices The set of choices to present. Either CHOICES_YES_NO or CHOICES_YES_NO_CANCEL
092     * @param default_choice The default choice. One of ANSWER_CANCEL, ANSWER_YES or ANSWER_NO.
093     * 
094     * @return The user's choice. (ANSWER_CANCEL, ANSWER_YES or ANSWER_NO)
095     */
096    public int askQuestion(String title, String question, int choices, int default_choice);
097
098}