| 1 | /* |
| 2 | * This file is part of lanterna (http://code.google.com/p/lanterna/). |
| 3 | * |
| 4 | * lanterna is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU Lesser General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public License |
| 15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | * |
| 17 | * Copyright (C) 2010-2015 Martin |
| 18 | */ |
| 19 | package com.googlecode.lanterna.terminal.swing; |
| 20 | |
| 21 | /** |
| 22 | * This interface can be used to control the backlog scrolling of a SwingTerminal. It's used as a callback by the |
| 23 | * {@code SwingTerminal} when it needs to fetch the scroll position and also used whenever the backlog changes to that |
| 24 | * some view class, like a scrollbar for example, can update its view accordingly. |
| 25 | * @author Martin |
| 26 | */ |
| 27 | public interface TerminalScrollController { |
| 28 | /** |
| 29 | * Called by the SwingTerminal when the terminal has changed or more lines are entered into the terminal |
| 30 | * @param totalSize Total number of lines in the backlog currently |
| 31 | * @param screenSize Number of lines covered by the terminal window at its current size |
| 32 | */ |
| 33 | void updateModel(int totalSize, int screenSize); |
| 34 | |
| 35 | /** |
| 36 | * Called by the SwingTerminal to know the 'offset' into the backlog. Returning 0 here will always draw the latest |
| 37 | * lines; if you return 5, it will draw from five lines into the backlog and skip the 5 most recent lines. |
| 38 | * @return According to this scroll controller, how far back into the backlog are we? |
| 39 | */ |
| 40 | int getScrollingOffset(); |
| 41 | |
| 42 | /** |
| 43 | * Implementation of {@link TerminalScrollController} that does nothing |
| 44 | */ |
| 45 | final class Null implements TerminalScrollController { |
| 46 | @Override |
| 47 | public void updateModel(int totalSize, int screenSize) { |
| 48 | } |
| 49 | |
| 50 | @Override |
| 51 | public int getScrollingOffset() { |
| 52 | return 0; |
| 53 | } |
| 54 | } |
| 55 | } |