+/*
+ * 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;
+
+import org.apache.log4j.spi.ThrowableRenderer;
+
+import java.io.File;
+import java.lang.reflect.Method;
+import java.net.URL;
+import java.security.CodeSource;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Enhanced implementation of ThrowableRenderer. Uses Throwable.getStackTrace
+ * if running on JDK 1.4 or later and delegates to DefaultThrowableRenderer.render
+ * on earlier virtual machines.
+ *
+ * @since 1.2.16
+ */
+public final class EnhancedThrowableRenderer implements ThrowableRenderer {
+ /**
+ * Throwable.getStackTrace() method.
+ */
+ private Method getStackTraceMethod;
+ /**
+ * StackTraceElement.getClassName() method.
+ */
+ private Method getClassNameMethod;
+
+
+ /**
+ * Construct new instance.
+ */
+ public EnhancedThrowableRenderer() {
+ try {
+ Class[] noArgs = null;
+ getStackTraceMethod = Throwable.class.getMethod("getStackTrace", noArgs);
+ Class ste = Class.forName("java.lang.StackTraceElement");
+ getClassNameMethod = ste.getMethod("getClassName", noArgs);
+ } catch(Exception ex) {
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public String[] doRender(final Throwable throwable) {
+ if (getStackTraceMethod != null) {
+ try {
+ Object[] noArgs = null;
+ Object[] elements = (Object[]) getStackTraceMethod.invoke(throwable, noArgs);
+ String[] lines = new String[elements.length + 1];
+ lines[0] = throwable.toString();
+ Map classMap = new HashMap();
+ for(int i = 0; i < elements.length; i++) {
+ lines[i+1] = formatElement(elements[i], classMap);
+ }
+ return lines;
+ } catch(Exception ex) {
+ }
+ }
+ return DefaultThrowableRenderer.render(throwable);
+ }
+
+ /**
+ * Format one element from stack trace.
+ * @param element element, may not be null.
+ * @param classMap map of class name to location.
+ * @return string representation of element.
+ */
+ private String formatElement(final Object element, final Map classMap) {
+ StringBuffer buf = new StringBuffer("\tat ");
+ buf.append(element);
+ try {
+ String className = getClassNameMethod.invoke(element, (Object[]) null).toString();
+ Object classDetails = classMap.get(className);
+ if (classDetails != null) {
+ buf.append(classDetails);
+ } else {
+ Class cls = findClass(className);
+ int detailStart = buf.length();
+ buf.append('[');
+ try {
+ CodeSource source = cls.getProtectionDomain().getCodeSource();
+ if (source != null) {
+ URL locationURL = source.getLocation();
+ if (locationURL != null) {
+ //
+ // if a file: URL
+ //
+ if ("file".equals(locationURL.getProtocol())) {
+ String path = locationURL.getPath();
+ if (path != null) {
+ //
+ // find the last file separator character
+ //
+ int lastSlash = path.lastIndexOf('/');
+ int lastBack = path.lastIndexOf(File.separatorChar);
+ if (lastBack > lastSlash) {
+ lastSlash = lastBack;
+ }
+ //
+ // if no separator or ends with separator (a directory)
+ // then output the URL, otherwise just the file name.
+ //
+ if (lastSlash <= 0 || lastSlash == path.length() - 1) {
+ buf.append(locationURL);
+ } else {
+ buf.append(path.substring(lastSlash + 1));
+ }
+ }
+ } else {
+ buf.append(locationURL);
+ }
+ }
+ }
+ } catch(SecurityException ex) {
+ }
+ buf.append(':');
+ Package pkg = cls.getPackage();
+ if (pkg != null) {
+ String implVersion = pkg.getImplementationVersion();
+ if (implVersion != null) {
+ buf.append(implVersion);
+ }
+ }
+ buf.append(']');
+ classMap.put(className, buf.substring(detailStart));
+ }
+ } catch(Exception ex) {
+ }
+ return buf.toString();
+ }
+
+ /**
+ * Find class given class name.
+ * @param className class name, may not be null.
+ * @return class, will not be null.
+ * @throws ClassNotFoundException thrown if class can not be found.
+ */
+ private Class findClass(final String className) throws ClassNotFoundException {
+ try {
+ return Thread.currentThread().getContextClassLoader().loadClass(className);
+ } catch (ClassNotFoundException e) {
+ try {
+ return Class.forName(className);
+ } catch (ClassNotFoundException e1) {
+ return getClass().getClassLoader().loadClass(className);
+ }
+ }
+ }
+
+}