| 1 | /* |
| 2 | * jDTAUS Core API |
| 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; |
| 22 | |
| 23 | /** |
| 24 | * Utility for loading classes. |
| 25 | * |
| 26 | * @author <a href="mailto:cs@schulte.it">Christian Schulte</a> |
| 27 | * @version $JDTAUS: ClassLoaderFactory.java 8641 2012-09-27 06:45:17Z schulte $ |
| 28 | */ |
| 29 | abstract class ClassLoaderFactory |
| 30 | { |
| 31 | |
| 32 | /** |
| 33 | * Name of the system property controlling the use of the context |
| 34 | * classloader. |
| 35 | */ |
| 36 | private static final String SYS_ENABLE_CONTEXT_CLASSLOADER = |
| 37 | "org.jdtaus.core.container.ClassLoaderFactory.enableContextClassloader"; |
| 38 | |
| 39 | /** |
| 40 | * Loads a class. |
| 41 | * <p>This method tries to load the class named {@code className} using the |
| 42 | * current thread's context classloader, if that classloader is enabled and |
| 43 | * not {@code null}, or the classloader of the given class, if no context |
| 44 | * classloader is available or the context classloader is disabled. Use of |
| 45 | * the context classloader must be explicitly enabled by setting the system |
| 46 | * property {@code org.jdtaus.core.container.ClassLoaderFactory.enableContextClassloader} |
| 47 | * to {@code true}.</p> |
| 48 | * |
| 49 | * @param clazz The clazz whose classloader to use for loading classes, if |
| 50 | * no thread context classloader is available or if the thread context |
| 51 | * classloader is disabled. |
| 52 | * @param className The name of the class to load. |
| 53 | * |
| 54 | * @return The class with name {@code className}. |
| 55 | * |
| 56 | * @throws ClassNotFoundException if no class matching {@code className} was |
| 57 | * found. |
| 58 | * @throws NullPointerException if {@code clazz} or {@code className} is |
| 59 | * {@code null}. |
| 60 | */ |
| 61 | static Class loadClass( final Class clazz, |
| 62 | final String className ) |
| 63 | throws ClassNotFoundException |
| 64 | { |
| 65 | if ( clazz == null ) |
| 66 | { |
| 67 | throw new NullPointerException( "clazz" ); |
| 68 | } |
| 69 | if ( className == null ) |
| 70 | { |
| 71 | throw new NullPointerException( "className" ); |
| 72 | } |
| 73 | |
| 74 | final ClassLoader classLoader; |
| 75 | if ( Boolean.getBoolean( SYS_ENABLE_CONTEXT_CLASSLOADER ) && |
| 76 | Thread.currentThread().getContextClassLoader() != null ) |
| 77 | { |
| 78 | classLoader = Thread.currentThread().getContextClassLoader(); |
| 79 | } |
| 80 | else |
| 81 | { |
| 82 | classLoader = clazz.getClassLoader() != null |
| 83 | ? clazz.getClassLoader() |
| 84 | : ClassLoader.getSystemClassLoader(); |
| 85 | |
| 86 | } |
| 87 | |
| 88 | return Class.forName( className, true, classLoader ); |
| 89 | } |
| 90 | |
| 91 | } |