| 1 | /* |
| 2 | * jDTAUS Core RI Client Container |
| 3 | * Copyright (C) 2005 Christian Schulte |
| 4 | * <cs@schulte.it> |
| 5 | * |
| 6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public |
| 8 | * License as published by the Free Software Foundation; either |
| 9 | * version 2.1 of the License, or any later version. |
| 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with this library; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | * |
| 20 | */ |
| 21 | package org.jdtaus.core.container.ri.client; |
| 22 | |
| 23 | import java.io.IOException; |
| 24 | import java.util.Enumeration; |
| 25 | |
| 26 | /** |
| 27 | * Utility for loading classes. |
| 28 | * |
| 29 | * @author <a href="mailto:cs@schulte.it">Christian Schulte</a> |
| 30 | * @version $JDTAUS: ClassLoaderFactory.java 8641 2012-09-27 06:45:17Z schulte $ |
| 31 | */ |
| 32 | abstract class ClassLoaderFactory |
| 33 | { |
| 34 | |
| 35 | /** |
| 36 | * Name of the system property controlling the use of the context |
| 37 | * classloader. |
| 38 | */ |
| 39 | private static final String SYS_ENABLE_CONTEXT_CLASSLOADER = |
| 40 | "org.jdtaus.core.container.ClassLoaderFactory.enableContextClassloader"; |
| 41 | |
| 42 | /** |
| 43 | * Loads a class. |
| 44 | * <p>This method tries to load the class named {@code className} using the |
| 45 | * current thread's context classloader, if that classloader is enabled and |
| 46 | * not {@code null}, or the classloader of the given class, if no context |
| 47 | * classloader is available or the context classloader is disabled. Use of |
| 48 | * the context classloader must be explicitly enabled by setting the system |
| 49 | * property {@code org.jdtaus.core.container.ClassLoaderFactory.enableContextClassloader} |
| 50 | * to {@code true}.</p> |
| 51 | * |
| 52 | * @param clazz The clazz whose classloader to use for loading classes, if |
| 53 | * no thread context classloader is available or if the thread context |
| 54 | * classloader is disabled. |
| 55 | * @param className The name of the class to load. |
| 56 | * |
| 57 | * @return The class with name {@code className}. |
| 58 | * |
| 59 | * @throws ClassNotFoundException if no class matching {@code className} was |
| 60 | * found. |
| 61 | * @throws NullPointerException if {@code clazz} or {@code className} is |
| 62 | * {@code null}. |
| 63 | */ |
| 64 | static Class loadClass( final Class clazz, |
| 65 | final String className ) |
| 66 | throws ClassNotFoundException |
| 67 | { |
| 68 | if ( clazz == null ) |
| 69 | { |
| 70 | throw new NullPointerException( "clazz" ); |
| 71 | } |
| 72 | if ( className == null ) |
| 73 | { |
| 74 | throw new NullPointerException( "className" ); |
| 75 | } |
| 76 | |
| 77 | return Class.forName( className, true, getClassLoader( clazz ) ); |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Loads resources. |
| 82 | * <p>This method tries to load resources matching {@code resourceName} |
| 83 | * using the current thread's context classloader, if that classloader is |
| 84 | * enabled and not {@code null}, or using the classloader of the given |
| 85 | * class, if the context classloader has been disabled. Use of the context |
| 86 | * classloader must be explicitly enabled by setting the system |
| 87 | * property {@code org.jdtaus.core.container.ClassLoaderFactory.enableContextClassloader} |
| 88 | * to {@code true}.</p> |
| 89 | * |
| 90 | * @param clazz The clazz whose classloader to use for loading classes, if |
| 91 | * no thread context classloader is available or if the thread context |
| 92 | * classloader is disabled. |
| 93 | * @param resourceName The name of the resources to load. |
| 94 | * |
| 95 | * @return All resources matching with name {@code resourceName}. |
| 96 | * |
| 97 | * @throws IOException if loading resources fails. |
| 98 | * @throws NullPointerException if {@code clazz} or {@code resourceName} is |
| 99 | * {@code null}. |
| 100 | */ |
| 101 | static Enumeration loadResources( final Class clazz, |
| 102 | final String resourceName ) |
| 103 | throws IOException |
| 104 | { |
| 105 | if ( clazz == null ) |
| 106 | { |
| 107 | throw new NullPointerException( "clazz" ); |
| 108 | } |
| 109 | if ( resourceName == null ) |
| 110 | { |
| 111 | throw new NullPointerException( "resourceName" ); |
| 112 | } |
| 113 | |
| 114 | return getClassLoader( clazz ).getResources( resourceName ); |
| 115 | } |
| 116 | |
| 117 | private static ClassLoader getClassLoader( final Class clazz ) |
| 118 | { |
| 119 | final ClassLoader classLoader; |
| 120 | if ( Boolean.getBoolean( SYS_ENABLE_CONTEXT_CLASSLOADER ) && |
| 121 | Thread.currentThread().getContextClassLoader() != null ) |
| 122 | { |
| 123 | classLoader = Thread.currentThread().getContextClassLoader(); |
| 124 | } |
| 125 | else |
| 126 | { |
| 127 | classLoader = clazz.getClassLoader() != null |
| 128 | ? clazz.getClassLoader() |
| 129 | : ClassLoader.getSystemClassLoader(); |
| 130 | |
| 131 | } |
| 132 | |
| 133 | return classLoader; |
| 134 | } |
| 135 | |
| 136 | } |