| /* |
| * Copyright 1999,2004 The Apache Software Foundation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.log4j.helpers; |
| |
| import java.net.URL; |
| |
| |
| |
| /** |
| Load resources (or images) from various sources. |
| |
| @author Ceki Gülcü |
| */ |
| public class Loader { |
| static final String TSTR = |
| "Caught Exception while in Loader.getResource. This may be innocuous."; |
| |
| // We conservatively assume that we are running under Java 1.x |
| private static boolean java1 = true; |
| private static boolean ignoreTCL = false; |
| |
| static { |
| String prop = OptionConverter.getSystemProperty("java.version", null); |
| |
| if (prop != null) { |
| int i = prop.indexOf('.'); |
| |
| if (i != -1) { |
| if (prop.charAt(i + 1) != '1') { |
| java1 = false; |
| } |
| } |
| } |
| |
| String ignoreTCLProp = |
| OptionConverter.getSystemProperty("log4j.ignoreTCL", null); |
| |
| if (ignoreTCLProp != null) { |
| ignoreTCL = OptionConverter.toBoolean(ignoreTCLProp, true); |
| } |
| } |
| |
| /** |
| * Get a resource by delegating to getResource(String). |
| * @param resource resource name |
| * @param clazz class, ignored. |
| * @return URL to resource or null. |
| * @deprecated as of 1.2. |
| */ |
| public static URL getResource(String resource, Class clazz) { |
| return getResource(resource); |
| } |
| |
| /** |
| This method will search for <code>resource</code> in different |
| places. The search order is as follows: |
| |
| <ol> |
| |
| <p><li>Search for <code>resource</code> using the thread context |
| class loader under Java2. This step is performed only if the <code> |
| skipTCL</code> parameter is false.</li> |
| |
| <p><li>If the previous step failed, search for <code>resource</code> using |
| the class loader that loaded this class (<code>Loader</code>).</li> |
| |
| <p><li>Try one last time with |
| <code>ClassLoader.getSystemResource(resource)</code>, that is is |
| using the system class loader in JDK 1.2 and virtual machine's |
| built-in class loader in JDK 1.1. |
| |
| </ol> |
| */ |
| public static URL getResource(String resource) { |
| ClassLoader classLoader = null; |
| URL url = null; |
| |
| try { |
| classLoader = getTCL(); |
| |
| if (classLoader != null) { |
| // LogLog.debug( |
| // "Trying to find [" + resource + "] using context classloader " |
| // + classLoader + "."); |
| url = classLoader.getResource(resource); |
| |
| if (url != null) { |
| return url; |
| } |
| } |
| |
| // We could not find resource. Ler us now try with the |
| // classloader that loaded this class. |
| classLoader = Loader.class.getClassLoader(); |
| |
| if (classLoader != null) { |
| // LogLog.debug( |
| // "Trying to find [" + resource + "] using " + classLoader |
| // + " class loader."); |
| url = classLoader.getResource(resource); |
| |
| if (url != null) { |
| return url; |
| } |
| } |
| } catch (Throwable t) { |
| // LogLog.warn(TSTR, t); |
| } |
| |
| // Last ditch attempt: get the resource from the class path. It |
| // may be the case that clazz was loaded by the Extentsion class |
| // loader which the parent of the system class loader. Hence the |
| // code below. |
| // LogLog.debug( |
| // "Trying to find [" + resource |
| // + "] using ClassLoader.getSystemResource()."); |
| |
| return ClassLoader.getSystemResource(resource); |
| } |
| |
| /** |
| Are we running under JDK 1.x? |
| */ |
| public static boolean isJava1() { |
| return java1; |
| } |
| |
| /** |
| * Get the Thread Context Loader which is a JDK 1.2 feature. If we |
| * are running under JDK 1.1 or anything else goes wrong the method |
| * returns <code>null<code>. |
| * |
| * */ |
| private static ClassLoader getTCL() { |
| return Thread.currentThread().getContextClassLoader(); |
| } |
| |
| /** |
| * If running under JDK 1.2 load the specified class using the |
| * <code>Thread</code> <code>contextClassLoader</code> if that |
| * fails try Class.forname. Under JDK 1.1 only Class.forName is |
| * used. |
| * |
| */ |
| public static Class loadClass(String clazz) throws ClassNotFoundException { |
| // Just call Class.forName(clazz) if we are running under JDK 1.1 |
| // or if we are instructed to ignore the TCL. |
| if (java1 || ignoreTCL) { |
| return Class.forName(clazz); |
| } else { |
| try { |
| return getTCL().loadClass(clazz); |
| } catch (Throwable e) { |
| // we reached here because tcl was null or because of a |
| // security exception, or because clazz could not be loaded... |
| // In any case we now try one more time |
| return Class.forName(clazz); |
| } |
| } |
| } |
| } |