Package org.assertj.core.util

Class Throwables

java.lang.Object

org.assertj.core.util.Throwables

public final class Throwables
extends Object

Utility methods related to Throwables.

Author:

Alex Ruiz, Daniel Zlotin

Method Summary

Modifier and Type	Method	Description
static <T extends Throwable> List<T>	addLineNumberToErrorMessages(List<? extends T> errors)
static void	appendStackTraceInCurrentThreadToThrowable(Throwable t, String methodToStartFrom)	Appends the stack trace of the current thread to the one in the given Throwable.
static List<String>	describeErrors(List<? extends Throwable> errors)
static StackTraceElement	getFirstStackTraceElementFromTest(StackTraceElement[] stacktrace)
static Throwable	getRootCause(Throwable throwable)	Get the root cause (i.e., the last non-null cause) from a Throwable.
static String	getStackTrace(Throwable throwable)	Get the stack trace from a Throwable as a String.
static void	removeAssertJRelatedElementsFromStackTrace(Throwable throwable)	Removes the AssertJ-related elements from the Throwable stack trace that have little value for end user, that is assertj elements and the ones coming from assertj (for example assertj calling some java jdk classes to build assertion errors dynamically).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

describeErrors

public static List<String> describeErrors(List<? extends Throwable> errors)

appendStackTraceInCurrentThreadToThrowable

public static void appendStackTraceInCurrentThreadToThrowable(Throwable t,
 String methodToStartFrom)

Appends the stack trace of the current thread to the one in the given Throwable.

Parameters:

t - the given Throwable.

methodToStartFrom - the name of the method used as the starting point of the current thread's stack trace.

removeAssertJRelatedElementsFromStackTrace

public static void removeAssertJRelatedElementsFromStackTrace(Throwable throwable)

Removes the AssertJ-related elements from the Throwable stack trace that have little value for end user, that is assertj elements and the ones coming from assertj (for example assertj calling some java jdk classes to build assertion errors dynamically).

Therefore, instead of seeing this:

 org.junit.ComparisonFailure: expected:<'[Ronaldo]'> but was:<'[Messi]'>
   at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
   at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
   at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
   at java.lang.reflect.Constructor.newInstance(Constructor.java:501)
   at org.assertj.core.error.ConstructorInvoker.newInstance(ConstructorInvoker.java:34)
   at org.assertj.core.error.ShouldBeEqual.newComparisonFailure(ShouldBeEqual.java:111)
   at org.assertj.core.error.ShouldBeEqual.comparisonFailure(ShouldBeEqual.java:103)
   at org.assertj.core.error.ShouldBeEqual.newAssertionError(ShouldBeEqual.java:81)
   at org.assertj.core.internal.Failures.failure(Failures.java:76)
   at org.assertj.core.internal.Objects.assertEqual(Objects.java:116)
   at org.assertj.core.api.AbstractAssert.isEqualTo(AbstractAssert.java:74)
   at examples.StackTraceFilterExample.main(StackTraceFilterExample.java:13)

We get this:

 org.junit.ComparisonFailure: expected:<'[Ronaldo]'> but was:<'[Messi]'>
   at examples.StackTraceFilterExample.main(StackTraceFilterExample.java:20)

Parameters:

throwable - the Throwable to filter stack trace.

getRootCause

public static Throwable getRootCause(Throwable throwable)

Get the root cause (i.e., the last non-null cause) from a Throwable.

Parameters:

throwable - the Throwable to get root cause from.

Returns:

the root cause if any, else null.

getStackTrace

public static String getStackTrace(Throwable throwable)

Get the stack trace from a Throwable as a String.

The result of this method vary by JDK version as this method uses Throwable.printStackTrace(java.io.PrintWriter). On JDK1.3 and earlier, the cause exception will not be shown unless the specified throwable alters printStackTrace.

Parameters:

throwable - the Throwable to get stack trace from.

Returns:

the stack trace as a String.

addLineNumberToErrorMessages

public static <T extends Throwable> List<T> addLineNumberToErrorMessages(List<? extends T> errors)

getFirstStackTraceElementFromTest

public static StackTraceElement getFirstStackTraceElementFromTest(StackTraceElement[] stacktrace)