stanford.cs106.util

Class ExceptionUtils

java.lang.Object

stanford.cs106.util.ExceptionUtils

public class ExceptionUtils
extends Object

This class contains utility code related to exceptions. A lot of the methods are related to examining an exception's stack trace to learn things about what methods/classes are on the call stack. This helps Practice-It figure out what went wrong in a student's code and where.

Method Summary

Modifier and Type	Method and Description
static String	filterStackTrace(String stackTrace, String... packagesToStrip)
static String	getCallingClassName(String... classNamesToSkip) The current class name on top of the current method call stack, ignoring any classes in the given list of classes to skip.
static int	getLineNumber(Throwable throwable, String className) The top-level line number within the given class name on which this exception occurred.
static int	getLineNumber(Throwable throwable, String className, String methodName) The top-level line number within the given class and method name on which this exception occurred in the given method.
static String	getMethodName(Throwable throwable, String className) The current method name within the given class name that is highest on the current method call stack.
static Throwable	getUnderlyingCause(Throwable t) The true cause of an exception that has occurred.
static String	stackTraceToString() The current stack trace as a multi-line String.
static String	stackTraceToString(int lines) The current stack trace as a multi-line String.
static String	stackTraceToString(Throwable throwable) The stack trace of the given exception as a multi-line String.
static String	stackTraceToString(Throwable throwable, int lines) The stack trace of the given exception as a multi-line String.

Methods inherited from class java.lang.Object

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

Method Detail

filterStackTrace

public static String filterStackTrace(String stackTrace,
                                      String... packagesToStrip)

stackTraceToString

public static String stackTraceToString()

The current stack trace as a multi-line String.

stackTraceToString

public static String stackTraceToString(int lines)

The current stack trace as a multi-line String.

stackTraceToString

public static String stackTraceToString(Throwable throwable)

The stack trace of the given exception as a multi-line String.

stackTraceToString

public static String stackTraceToString(Throwable throwable,
                                        int lines)

The stack trace of the given exception as a multi-line String.

getLineNumber

public static int getLineNumber(Throwable throwable,
                                String className)

The top-level line number within the given class name on which this exception occurred. For example, if you have the exception:

 RuntimeException
     at Foo.java line 42
     at Bar.java line 18
     at Bar.java line 29
 

and you ask for the line number from Bar, returns 18.

Returns:

-1 if the exception doesn't contain a stack frame for this class

getLineNumber

public static int getLineNumber(Throwable throwable,
                                String className,
                                String methodName)

The top-level line number within the given class and method name on which this exception occurred in the given method. For example, if you have the exception:

 RuntimeException
     at Foo.java:method0() line 42
     at Bar.java:method1() line 96
     at Bar.java:method2() line 18
     at Bar.java:method2() line 29
 

and you ask for the line number from Bar, method2, returns 18.

Returns:

-1 if the exception doesn't contain a stack frame for this class/method

getCallingClassName

public static String getCallingClassName(String... classNamesToSkip)

The current class name on top of the current method call stack, ignoring any classes in the given list of classes to skip.

Returns:

the class name, or null if none can be determined (unlikely)

getMethodName

public static String getMethodName(Throwable throwable,
                                   String className)

The current method name within the given class name that is highest on the current method call stack.

Returns:

the method name, or empty string if no method from that class is on the stack

getUnderlyingCause

public static Throwable getUnderlyingCause(Throwable t)

The true cause of an exception that has occurred. Basically calls t.getCause() until it hits the top level. If passed null, returns null.