| 1 | /* |
| 2 | * $Id: NativeLibraryLoader.java,v 1.8 2005/06/29 07:35:21 hastings Exp $ |
| 3 | * |
| 4 | * (c) Copyright, Moebius Solutions, Inc., 2004 |
| 5 | * |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * This material may be reproduced by or for the U. S. Government |
| 9 | * pursuant to the copyright license under the clause at |
| 10 | * DFARS 252.227-7014 (OCT 2001). |
| 11 | */ |
| 12 | |
| 13 | package com.moesol.bindings; |
| 14 | |
| 15 | import java.io.File; |
| 16 | import java.util.HashSet; |
| 17 | import java.util.Set; |
| 18 | import java.util.logging.Level; |
| 19 | import java.util.logging.Logger; |
| 20 | import java.util.prefs.Preferences; |
| 21 | |
| 22 | import com.moesol.util.DeveloperProperties; |
| 23 | |
| 24 | /** |
| 25 | * @author robert |
| 26 | */ |
| 27 | public class NativeLibraryLoader { |
| 28 | /** |
| 29 | * Calls System.loadLibrary and if that fails, uses Preferences to try to |
| 30 | * find the full path to the library. If that fails it uses |
| 31 | * DeveloperProperties to try to find the full path to the library. |
| 32 | * |
| 33 | * The preference tree com/moesol/bindings/NativeLibraryLoader is checked |
| 34 | * for name + ".library.path". |
| 35 | * |
| 36 | * The DeveloperProperties is checked for name + ".library.path". |
| 37 | * |
| 38 | * In both cases the value should be the directory that contains the |
| 39 | * library. |
| 40 | * |
| 41 | * @param name |
| 42 | * The library to load. |
| 43 | */ |
| 44 | public static void loadLibrary(String name) { |
| 45 | try { |
| 46 | System.loadLibrary(name); |
| 47 | } catch (UnsatisfiedLinkError e) { |
| 48 | if (!findAndLoad(name)) { |
| 49 | throw e; |
| 50 | } |
| 51 | } |
| 52 | } |
| 53 | private static boolean findAndLoad(String name) { |
| 54 | String directory; |
| 55 | |
| 56 | directory = findUsingDevProperties(name); |
| 57 | if (checkDirectory(directory, name)) { |
| 58 | load(directory, name); |
| 59 | return true; |
| 60 | } |
| 61 | |
| 62 | directory = findUsingPrefs(name); |
| 63 | if (checkDirectory(directory, name)) { |
| 64 | load(directory, name); |
| 65 | return true; |
| 66 | } |
| 67 | return false; |
| 68 | } |
| 69 | |
| 70 | static boolean checkDirectory(String directory, String name) { |
| 71 | if (directory == null) { |
| 72 | return false; |
| 73 | } |
| 74 | File check = new File(buildFullPathToLibrary(directory, name)); |
| 75 | return check.canRead(); |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * @param name |
| 80 | * @return property key |
| 81 | */ |
| 82 | static String buildKeyForLibrary(String name) { |
| 83 | return name + ".library.path"; |
| 84 | } |
| 85 | /** |
| 86 | * Prepend directory_path and append the system shared library/dll extension |
| 87 | * to compute the full path to the library. |
| 88 | * |
| 89 | * @param director_path |
| 90 | * @param name |
| 91 | * @return full path to library |
| 92 | */ |
| 93 | static String buildFullPathToLibrary(String director_path, String name) { |
| 94 | return director_path + File.separator + System.mapLibraryName(name); |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * @param name |
| 99 | * @return path using dev properties |
| 100 | */ |
| 101 | static String findUsingDevProperties(String name) { |
| 102 | return DeveloperProperties.getProperty(buildKeyForLibrary(name)); |
| 103 | } |
| 104 | static String findUsingPrefs(String name) { |
| 105 | Preferences package_prefs = Preferences.systemNodeForPackage(NativeLibraryLoader.class); |
| 106 | Preferences class_prefs = package_prefs.node("NativeLibraryLoader"); |
| 107 | return class_prefs.get(buildKeyForLibrary(name), null); |
| 108 | } |
| 109 | private static void load(String directory, String name) { |
| 110 | String full_path = buildFullPathToLibrary(directory, name); |
| 111 | maybeLog(full_path); |
| 112 | System.load(full_path); |
| 113 | } |
| 114 | /** |
| 115 | * If logging is on and we have not already logged this |
| 116 | * library, output a log message |
| 117 | * |
| 118 | * @param full_path |
| 119 | */ |
| 120 | private static void maybeLog(String full_path) { |
| 121 | if (logger.isLoggable(Level.INFO)) { |
| 122 | if (!s_loaded.contains(full_path)) { |
| 123 | logger.log(Level.INFO, "Loading: {0}", full_path); |
| 124 | s_loaded.add(full_path); |
| 125 | } |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | private static Set s_loaded = new HashSet(); |
| 130 | private static Logger logger = Logger.getLogger(NativeLibraryLoader.class.getName()); |
| 131 | } |