| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
| Activator |
|
| 2.0;2 |
| 1 | /** | |
| 2 | * Distribution License: | |
| 3 | * JSword is free software; you can redistribute it and/or modify it under | |
| 4 | * the terms of the GNU Lesser General Public License, version 2.1 or later | |
| 5 | * as published by the Free Software Foundation. This program is distributed | |
| 6 | * in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even | |
| 7 | * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
| 8 | * See the GNU Lesser General Public License for more details. | |
| 9 | * | |
| 10 | * The License is available on the internet at: | |
| 11 | * http://www.gnu.org/copyleft/lgpl.html | |
| 12 | * or by writing to: | |
| 13 | * Free Software Foundation, Inc. | |
| 14 | * 59 Temple Place - Suite 330 | |
| 15 | * Boston, MA 02111-1307, USA | |
| 16 | * | |
| 17 | * © CrossWire Bible Society, 2005 - 2016 | |
| 18 | * | |
| 19 | */ | |
| 20 | package org.crosswire.common.activate; | |
| 21 | ||
| 22 | import java.util.HashSet; | |
| 23 | import java.util.Set; | |
| 24 | ||
| 25 | /** | |
| 26 | * Manager for instances of Activatable. | |
| 27 | * | |
| 28 | * Activator should be used to manage all activate()ions and deactivate()ions so | |
| 29 | * that it can keep a track of exactly what is active and what can be | |
| 30 | * deactivated is save memory. | |
| 31 | * | |
| 32 | * @see gnu.lgpl.License The GNU Lesser General Public License for details. | |
| 33 | * @author Joe Walker | |
| 34 | */ | |
| 35 | public final class Activator { | |
| 36 | /** | |
| 37 | * Prevent instantiation | |
| 38 | */ | |
| 39 | 0 | private Activator() { |
| 40 | // singleton - no set-up needed | |
| 41 | 0 | } |
| 42 | ||
| 43 | /** | |
| 44 | * Check that a subject is activated and call activate() if not. | |
| 45 | * | |
| 46 | * @param subject | |
| 47 | * The thing to activate | |
| 48 | */ | |
| 49 | public static void activate(Activatable subject) { | |
| 50 | 0 | if (!activated.contains(subject) && subject != null) { |
| 51 | 0 | subject.activate(lock); |
| 52 | 0 | activated.add(subject); |
| 53 | } | |
| 54 | 0 | } |
| 55 | ||
| 56 | /** | |
| 57 | * If we need to tighten things up a bit we can save memory with this | |
| 58 | * | |
| 59 | * @param amount the amount by which to to reduce memory | |
| 60 | */ | |
| 61 | public static void reduceMemoryUsage(Kill amount) { | |
| 62 | 0 | amount.reduceMemoryUsage(); |
| 63 | 0 | } |
| 64 | ||
| 65 | /** | |
| 66 | * Deactivate an Activatable object. It is safe to activate() something and | |
| 67 | * then forget to deactivate() it since we keep a track of activated objects | |
| 68 | * and will automatically deactivate() when needed, so this method should | |
| 69 | * only be used when we are sure that something will not be needed again. | |
| 70 | * | |
| 71 | * @param subject | |
| 72 | * The thing to deactivate | |
| 73 | */ | |
| 74 | public static void deactivate(Activatable subject) { | |
| 75 | 0 | if (activated.contains(subject) && subject != null) { |
| 76 | 0 | subject.deactivate(lock); |
| 77 | 0 | activated.remove(subject); |
| 78 | } | |
| 79 | 0 | } |
| 80 | ||
| 81 | public static void deactivateAll() { | |
| 82 | 0 | for (Activatable item : activated) { |
| 83 | 0 | deactivate(item); |
| 84 | } | |
| 85 | 0 | } |
| 86 | ||
| 87 | /** | |
| 88 | * The list of things that we have activated | |
| 89 | */ | |
| 90 | 0 | private static Set<Activatable> activated = new HashSet<Activatable>(); |
| 91 | ||
| 92 | /** | |
| 93 | * The object we use to prevent others from | |
| 94 | */ | |
| 95 | 0 | private static Lock lock = new Lock(); |
| 96 | } |