/*
* Copyright 2002-2005 the original author or authors.
*
* 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.
*/
/**
* Utility class for diagnostic purposes, to analyze the
* ClassLoader hierarchy for any given object or class loader.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since 02 April 2001
* @see java.lang.ClassLoader
*/
public abstract class ClassLoaderUtils {
/**
* Show the class loader hierarchy for this class.
* Uses default line break and tab text characters.
* @param obj object to analyze loader hierarchy for
* @param role a description of the role of this class in the application
* (e.g., "servlet" or "EJB reference")
* @return a String showing the class loader hierarchy for this class
*/
public static String showClassLoaderHierarchy(Object obj, String role) {
return showClassLoaderHierarchy(obj, role, "\n", "\t");
}
/**
* Show the class loader hierarchy for this class.
* @param obj object to analyze loader hierarchy for
* @param role a description of the role of this class in the application
* (e.g., "servlet" or "EJB reference")
* @param lineBreak line break
* @param tabText text to use to set tabs
* @return a String showing the class loader hierarchy for this class
*/
public static String showClassLoaderHierarchy(Object obj, String role, String lineBreak, String tabText) {
String s = "object of " + obj.getClass() + ": role is " + role + lineBreak;
return s + showClassLoaderHierarchy(obj.getClass().getClassLoader(), lineBreak, tabText, 0);
}
/**
* Show the class loader hierarchy for the given class loader.
* Uses default line break and tab text characters.
* @param cl class loader to analyze hierarchy for
* @return a String showing the class loader hierarchy for this class
*/
public static String showClassLoaderHierarchy(ClassLoader cl) {
return showClassLoaderHierarchy(cl, "\n", "\t");
}
/**
* Show the class loader hierarchy for the given class loader.
* @param cl class loader to analyze hierarchy for
* @param lineBreak line break
* @param tabText text to use to set tabs
* @return a String showing the class loader hierarchy for this class
*/
public static String showClassLoaderHierarchy(ClassLoader cl, String lineBreak, String tabText) {
return showClassLoaderHierarchy(cl, lineBreak, tabText, 0);
}
/**
* Show the class loader hierarchy for the given class loader.
* @param cl class loader to analyze hierarchy for
* @param lineBreak line break
* @param tabText text to use to set tabs
* @param indent nesting level (from 0) of this loader; used in pretty printing
* @return a String showing the class loader hierarchy for this class
*/
private static String showClassLoaderHierarchy(ClassLoader cl, String lineBreak, String tabText, int indent) {
if (cl == null) {
ClassLoader ccl = Thread.currentThread().getContextClassLoader();
return "context class loader=[" + ccl + "] hashCode=" + ccl.hashCode();
}
StringBuffer buf = new StringBuffer();
for (int i = 0; i < indent; i++) {
buf.append(tabText);
}
buf.append("[").append(cl).append("] hashCode=").append(cl.hashCode()).append(lineBreak);
ClassLoader parent = cl.getParent();
return buf.toString() + showClassLoaderHierarchy(parent, lineBreak, tabText, indent + 1);
}
}