--- /dev/null
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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;
+import java.lang.reflect.Method;
+import java.lang.reflect.InvocationTargetException;
+import java.io.InterruptedIOException;
+
+
+/**
+ 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
+ static private boolean java1 = true;
+
+ static private 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. If that fails, search for
+ <code>resource</code> using the class loader that loaded this
+ class (<code>Loader</code>). Under JDK 1.1, only the the class
+ loader that loaded this class (<code>Loader</code>) is used.
+
+ <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>
+ */
+ static public URL getResource(String resource) {
+ ClassLoader classLoader = null;
+ URL url = null;
+
+ try {
+ if(!java1 && !ignoreTCL) {
+ 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(IllegalAccessException t) {
+ LogLog.warn(TSTR, t);
+ } catch(InvocationTargetException t) {
+ if (t.getTargetException() instanceof InterruptedException
+ || t.getTargetException() instanceof InterruptedIOException) {
+ Thread.currentThread().interrupt();
+ }
+ LogLog.warn(TSTR, t);
+ } catch(Throwable t) {
+ //
+ // can't be InterruptedException or InterruptedIOException
+ // since not declared, must be error or RuntimeError.
+ 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() throws IllegalAccessException,
+ InvocationTargetException {
+
+ // Are we running on a JDK 1.2 or later system?
+ Method method = null;
+ try {
+ method = Thread.class.getMethod("getContextClassLoader", null);
+ } catch (NoSuchMethodException e) {
+ // We are running on JDK 1.1
+ return null;
+ }
+
+ return (ClassLoader) method.invoke(Thread.currentThread(), null);
+ }
+
+
+
+ /**
+ * 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.
+ *
+ */
+ static public 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);
+ }
+ // 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
+ catch(InvocationTargetException e) {
+ if (e.getTargetException() instanceof InterruptedException
+ || e.getTargetException() instanceof InterruptedIOException) {
+ Thread.currentThread().interrupt();
+ }
+ } catch(Throwable t) {
+ }
+ }
+ return Class.forName(clazz);
+ }
+}
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