001 /* 002 * Created on Dec 13, 2008 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with 005 * the License. You may obtain a copy of the License at 006 * 007 * http://www.apache.org/licenses/LICENSE-2.0 008 * 009 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on 010 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the 011 * specific language governing permissions and limitations under the License. 012 * 013 * Copyright @2008-2011-2010 the original author or authors. 014 */ 015 package org.fest.util; 016 017 import static org.fest.util.Collections.list; 018 019 import java.util.*; 020 021 /** 022 * Utility methods related to <code>{@link Throwable}</code>s. 023 * 024 * @author Alex Ruiz 025 */ 026 public final class Throwables { 027 028 /** 029 * Appends the stack trace of the current thread to the one in the given <code>{@link Throwable}</code>. 030 * @param t the given {@code Throwable}. 031 * @param methodToStartFrom the name of the method used as the starting point of the current thread's stack trace. 032 */ 033 public static void appendCurrentThreadStackTraceToThrowable(Throwable t, String methodToStartFrom) { 034 List<StackTraceElement> stackTrace = list(t.getStackTrace()); 035 stackTrace.addAll(currentThreadStackTrace(methodToStartFrom)); 036 t.setStackTrace(stackTrace.toArray(new StackTraceElement[stackTrace.size()])); 037 } 038 039 /** 040 * Removes the Fest elements from the <code>{@link Throwable}</code> stack trace that have little value for end user. 041 * <pre>So instead of seeing this: 042 043 org.junit.ComparisonFailure: expected:<'[Ronaldo]'> but was:<'[Messi]'> 044 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 045 at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) 046 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) 047 at java.lang.reflect.Constructor.newInstance(Constructor.java:501) 048 at org.fest.assertions.error.ConstructorInvoker.newInstance(ConstructorInvoker.java:34) 049 at org.fest.assertions.error.ShouldBeEqual.newComparisonFailure(ShouldBeEqual.java:111) 050 at org.fest.assertions.error.ShouldBeEqual.comparisonFailure(ShouldBeEqual.java:103) 051 at org.fest.assertions.error.ShouldBeEqual.newAssertionError(ShouldBeEqual.java:81) 052 at org.fest.assertions.internal.Failures.failure(Failures.java:76) 053 at org.fest.assertions.internal.Objects.assertEqual(Objects.java:116) 054 at org.fest.assertions.api.AbstractAssert.isEqualTo(AbstractAssert.java:74) 055 at examples.StackTraceFilterExample.main(StackTraceFilterExample.java:13) 056 057 We get this: 058 059 org.junit.ComparisonFailure: expected:<'[Ronaldo]'> but was:<'[Messi]'> 060 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 061 at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) 062 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) 063 at examples.StackTraceFilterExample.main(StackTraceFilterExample.java:20) 064 * </pre> 065 * @param throwable the {@code Throwable} to filter stack trace. 066 */ 067 public static void removeFestRelatedElementsFromStackTrace(Throwable throwable) { 068 List<StackTraceElement> filteredStackTrace = list(throwable.getStackTrace()); 069 StackTraceElement previousStackTraceElement = null; 070 for (StackTraceElement stackTraceElement : throwable.getStackTrace()) { 071 if (stackTraceElement.getClassName().contains("org.fest")) { 072 filteredStackTrace.remove(stackTraceElement); 073 // handle the case when Fest builds a ComparisonFailure by reflection (see ShouldBeEqual.newAssertionError 074 // method), the stack trace looks like : 075 // java.lang.reflect.Constructor.newInstance(Constructor.java:501), 076 // org.fest.assertions.error.ConstructorInvoker.newInstance(ConstructorInvoker.java:34), 077 // we want to get rid of java.lang.reflect.Constructor.newInstance element because it is related to Fest. 078 if (stackTraceElementClassNameIs(previousStackTraceElement, "java.lang.reflect.Constructor") 079 && stackTraceElement.getClassName().contains("org.fest.assertions.error.ConstructorInvoker")) { 080 filteredStackTrace.remove(previousStackTraceElement); 081 } 082 } 083 previousStackTraceElement = stackTraceElement; 084 } 085 throwable.setStackTrace(filteredStackTrace.toArray(new StackTraceElement[filteredStackTrace.size()])); 086 } 087 088 private static boolean stackTraceElementClassNameIs(StackTraceElement stackTraceElement, String className) { 089 if (stackTraceElement == null) return false; 090 return stackTraceElement.getClassName().equals(className); 091 } 092 093 private static List<StackTraceElement> currentThreadStackTrace(String methodToStartFrom) { 094 List<StackTraceElement> filtered = stackTraceInCurrentThread(); 095 List<StackTraceElement> toRemove = new ArrayList<StackTraceElement>(); 096 for (StackTraceElement e : filtered) { 097 if (methodToStartFrom.equals(e.getMethodName())) break; 098 toRemove.add(e); 099 } 100 filtered.removeAll(toRemove); 101 return filtered; 102 } 103 104 private static List<StackTraceElement> stackTraceInCurrentThread() { 105 return list(StackTraces.instance().stackTraceInCurrentThread()); 106 } 107 108 private Throwables() {} 109 }