001: /*
002: * Copyright 2002-2005 the original author or authors.
003: *
004: * Licensed under the Apache License, Version 2.0 (the "License");
005: * you may not use this file except in compliance with the License.
006: * You may obtain a copy of the License at
007: *
008: * http://www.apache.org/licenses/LICENSE-2.0
009: *
010: * Unless required by applicable law or agreed to in writing, software
011: * distributed under the License is distributed on an "AS IS" BASIS,
012: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013: * See the License for the specific language governing permissions and
014: * limitations under the License.
015: */
016:
017: package org.springframework.util;
018:
019: /**
020: * Utility class for diagnostic purposes, to analyze the
021: * ClassLoader hierarchy for any given object or class loader.
022: *
023: * @author Rod Johnson
024: * @author Juergen Hoeller
025: * @since 02 April 2001
026: * @see java.lang.ClassLoader
027: */
028: public abstract class ClassLoaderUtils {
029:
030: /**
031: * Show the class loader hierarchy for this class.
032: * Uses default line break and tab text characters.
033: * @param obj object to analyze loader hierarchy for
034: * @param role a description of the role of this class in the application
035: * (e.g., "servlet" or "EJB reference")
036: * @return a String showing the class loader hierarchy for this class
037: */
038: public static String showClassLoaderHierarchy(Object obj,
039: String role) {
040: return showClassLoaderHierarchy(obj, role, "\n", "\t");
041: }
042:
043: /**
044: * Show the class loader hierarchy for this class.
045: * @param obj object to analyze loader hierarchy for
046: * @param role a description of the role of this class in the application
047: * (e.g., "servlet" or "EJB reference")
048: * @param lineBreak line break
049: * @param tabText text to use to set tabs
050: * @return a String showing the class loader hierarchy for this class
051: */
052: public static String showClassLoaderHierarchy(Object obj,
053: String role, String lineBreak, String tabText) {
054: String s = "object of " + obj.getClass() + ": role is " + role
055: + lineBreak;
056: return s
057: + showClassLoaderHierarchy(obj.getClass()
058: .getClassLoader(), lineBreak, tabText, 0);
059: }
060:
061: /**
062: * Show the class loader hierarchy for the given class loader.
063: * Uses default line break and tab text characters.
064: * @param cl class loader to analyze hierarchy for
065: * @return a String showing the class loader hierarchy for this class
066: */
067: public static String showClassLoaderHierarchy(ClassLoader cl) {
068: return showClassLoaderHierarchy(cl, "\n", "\t");
069: }
070:
071: /**
072: * Show the class loader hierarchy for the given class loader.
073: * @param cl class loader to analyze hierarchy for
074: * @param lineBreak line break
075: * @param tabText text to use to set tabs
076: * @return a String showing the class loader hierarchy for this class
077: */
078: public static String showClassLoaderHierarchy(ClassLoader cl,
079: String lineBreak, String tabText) {
080: return showClassLoaderHierarchy(cl, lineBreak, tabText, 0);
081: }
082:
083: /**
084: * Show the class loader hierarchy for the given class loader.
085: * @param cl class loader to analyze hierarchy for
086: * @param lineBreak line break
087: * @param tabText text to use to set tabs
088: * @param indent nesting level (from 0) of this loader; used in pretty printing
089: * @return a String showing the class loader hierarchy for this class
090: */
091: private static String showClassLoaderHierarchy(ClassLoader cl,
092: String lineBreak, String tabText, int indent) {
093: if (cl == null) {
094: ClassLoader ccl = Thread.currentThread()
095: .getContextClassLoader();
096: return "context class loader=[" + ccl + "] hashCode="
097: + ccl.hashCode();
098: }
099: StringBuffer buf = new StringBuffer();
100: for (int i = 0; i < indent; i++) {
101: buf.append(tabText);
102: }
103: buf.append("[").append(cl).append("] hashCode=").append(
104: cl.hashCode()).append(lineBreak);
105: ClassLoader parent = cl.getParent();
106: return buf.toString()
107: + showClassLoaderHierarchy(parent, lineBreak, tabText,
108: indent + 1);
109: }
110:
111: }
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