addCauseMethodName
public static void addCauseMethodName(String methodName)
Adds to the list of method names used in the search for Throwable
objects.
methodName
- the methodName to add to the list, null
and empty strings are ignored
getCause
public static Throwable getCause(Throwable throwable)
Introspects the
Throwable
to obtain the cause.
The method searches for methods with specific names that return a
Throwable
object. This will pick up most wrapping exceptions,
including those from JDK 1.4, and
NestableException
.
The method names can be added to using
addCauseMethodName(String)
.
The default list searched for are:
getCause()
getNextException()
getTargetException()
getException()
getSourceException()
getRootCause()
getCausedByException()
getNested()
In the absence of any such method, the object is inspected for a
detail
field assignable to a
Throwable
.
If none of the above is found, returns
null
.
throwable
- the throwable to introspect for a cause, may be null
- the cause of the
Throwable
,
null
if none found or null throwable input
getCause
public static Throwable getCause(Throwable throwable,
String[] methodNames)
Introspects the
Throwable
to obtain the cause.
- Try known exception types.
- Try the supplied array of method names.
- Try the field 'detail'.
A
null
set of method names means use the default set.
A
null
in the set of method names will be ignored.
throwable
- the throwable to introspect for a cause, may be nullmethodNames
- the method names, null treated as default set
- the cause of the
Throwable
,
null
if none found or null throwable input
getFullStackTrace
public static String getFullStackTrace(Throwable throwable)
A way to get the entire nested stack-trace of an throwable.
The result of this method is highly dependent on the JDK version
and whether the exceptions override printStackTrace or not.
throwable
- the Throwable
to be examined
- the nested stack trace, with the root cause first
getMessage
public static String getMessage(Throwable th)
Gets a short message summarising the exception.
The message returned is of the form
{ClassNameWithoutPackage}: {ThrowableMessage}
th
- the throwable to get a message for, null returns empty string
getRootCause
public static Throwable getRootCause(Throwable throwable)
Introspects the
Throwable
to obtain the root cause.
This method walks through the exception chain to the last element,
"root" of the tree, using
getCause(Throwable)
, and
returns that exception.
From version 2.2, this method handles recursive cause structures
that might otherwise cause infinite loops. If the throwable parameter
has a cause of itself, then null will be returned. If the throwable
parameter cause chain loops, the last element in the chain before the
loop is returned.
throwable
- the throwable to get the root cause for, may be null
- the root cause of the
Throwable
,
null
if none found or null throwable input
getRootCauseMessage
public static String getRootCauseMessage(Throwable th)
Gets a short message summarising the root cause exception.
The message returned is of the form
{ClassNameWithoutPackage}: {ThrowableMessage}
th
- the throwable to get a message for, null returns empty string
getRootCauseStackTrace
public static String[] getRootCauseStackTrace(Throwable throwable)
Creates a compact stack trace for the root cause of the supplied
Throwable
.
The output of this method is consistent across JDK versions.
It consists of the root exception followed by each of its wrapping
exceptions separated by '[wrapped]'. Note that this is the opposite
order to the JDK1.4 display.
throwable
- the throwable to examine, may be null
- an array of stack trace frames, never null
getStackFrames
public static String[] getStackFrames(Throwable throwable)
Captures the stack trace associated with the specified
Throwable
object, decomposing it into a list of
stack frames.
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.
throwable
- the Throwable
to examine, may be null
- an array of strings describing each stack frame, never null
getStackTrace
public static String getStackTrace(Throwable throwable)
Gets 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.
throwable
- the Throwable
to be examined
- the stack trace as generated by the exception's
printStackTrace(PrintWriter)
method
getThrowableCount
public static int getThrowableCount(Throwable throwable)
Counts the number of
Throwable
objects in the
exception chain.
A throwable without cause will return
1
.
A throwable with one cause will return
2
and so on.
A
null
throwable will return
0
.
From version 2.2, this method handles recursive cause structures
that might otherwise cause infinite loops. The cause chain is
processed until the end is reached, or until the next item in the
chain is already in the result set.
throwable
- the throwable to inspect, may be null
- the count of throwables, zero if null input
getThrowableList
public static List getThrowableList(Throwable throwable)
Returns the list of
Throwable
objects in the
exception chain.
A throwable without cause will return a list containing
one element - the input throwable.
A throwable with one cause will return a list containing
two elements. - the input throwable and the cause throwable.
A
null
throwable will return a list of size zero.
This method handles recursive cause structures that might
otherwise cause infinite loops. The cause chain is processed until
the end is reached, or until the next item in the chain is already
in the result set.
throwable
- the throwable to inspect, may be null
- the list of throwables, never null
getThrowables
public static Throwable[] getThrowables(Throwable throwable)
Returns the list of
Throwable
objects in the
exception chain.
A throwable without cause will return an array containing
one element - the input throwable.
A throwable with one cause will return an array containing
two elements. - the input throwable and the cause throwable.
A
null
throwable will return an array of size zero.
From version 2.2, this method handles recursive cause structures
that might otherwise cause infinite loops. The cause chain is
processed until the end is reached, or until the next item in the
chain is already in the result set.
throwable
- the throwable to inspect, may be null
- the array of throwables, never null
indexOfThrowable
public static int indexOfThrowable(Throwable throwable,
Class clazz)
Returns the (zero based) index of the first
Throwable
that matches the specified class (exactly) in the exception chain.
Subclasses of the specified class do not match - see
indexOfType(Throwable,Class)
for the opposite.
A
null
throwable returns
-1
.
A
null
type returns
-1
.
No match in the chain returns
-1
.
throwable
- the throwable to inspect, may be nullclazz
- the class to search for, subclasses do not match, null returns -1
- the index into the throwable chain, -1 if no match or null input
indexOfThrowable
public static int indexOfThrowable(Throwable throwable,
Class clazz,
int fromIndex)
Returns the (zero based) index of the first
Throwable
that matches the specified type in the exception chain from
a specified index.
Subclasses of the specified class do not match - see
indexOfType(Throwable,Class,int)
for the opposite.
A
null
throwable returns
-1
.
A
null
type returns
-1
.
No match in the chain returns
-1
.
A negative start index is treated as zero.
A start index greater than the number of throwables returns
-1
.
throwable
- the throwable to inspect, may be nullclazz
- the class to search for, subclasses do not match, null returns -1fromIndex
- the (zero based) index of the starting position,
negative treated as zero, larger than chain size returns -1
- the index into the throwable chain, -1 if no match or null input
indexOfType
public static int indexOfType(Throwable throwable,
Class type)
Returns the (zero based) index of the first
Throwable
that matches the specified class or subclass in the exception chain.
Subclasses of the specified class do match - see
indexOfThrowable(Throwable,Class)
for the opposite.
A
null
throwable returns
-1
.
A
null
type returns
-1
.
No match in the chain returns
-1
.
throwable
- the throwable to inspect, may be nulltype
- the type to search for, subclasses match, null returns -1
- the index into the throwable chain, -1 if no match or null input
indexOfType
public static int indexOfType(Throwable throwable,
Class type,
int fromIndex)
Returns the (zero based) index of the first
Throwable
that matches the specified type in the exception chain from
a specified index.
Subclasses of the specified class do match - see
indexOfThrowable(Throwable,Class)
for the opposite.
A
null
throwable returns
-1
.
A
null
type returns
-1
.
No match in the chain returns
-1
.
A negative start index is treated as zero.
A start index greater than the number of throwables returns
-1
.
throwable
- the throwable to inspect, may be nulltype
- the type to search for, subclasses match, null returns -1fromIndex
- the (zero based) index of the starting position,
negative treated as zero, larger than chain size returns -1
- the index into the throwable chain, -1 if no match or null input
isCauseMethodName
public static boolean isCauseMethodName(String methodName)
Tests if the list of method names used in the search for Throwable
objects include the given name.
methodName
- the methodName to search in the list.
- if the list of method names used in the search for
Throwable
objects include the given name.
isNestedThrowable
public static boolean isNestedThrowable(Throwable throwable)
Checks whether this
Throwable
class can store a cause.
This method does
not check whether it actually does store a cause.
throwable
- the Throwable
to examine, may be null
- boolean
true
if nested otherwise false
isThrowableNested
public static boolean isThrowableNested()
Checks if the Throwable class has a
getCause
method.
This is true for JDK 1.4 and above.
- true if Throwable is nestable
printRootCauseStackTrace
public static void printRootCauseStackTrace(Throwable throwable)
Prints a compact stack trace for the root cause of a throwable
to
System.err
.
The compact stack trace starts with the root cause and prints
stack frames up to the place where it was caught and wrapped.
Then it prints the wrapped exception and continues with stack frames
until the wrapper exception is caught and wrapped again, etc.
The output of this method is consistent across JDK versions.
Note that this is the opposite order to the JDK1.4 display.
The method is equivalent to
printStackTrace
for throwables
that don't have nested causes.
throwable
- the throwable to output
printRootCauseStackTrace
public static void printRootCauseStackTrace(Throwable throwable,
PrintStream stream)
Prints a compact stack trace for the root cause of a throwable.
The compact stack trace starts with the root cause and prints
stack frames up to the place where it was caught and wrapped.
Then it prints the wrapped exception and continues with stack frames
until the wrapper exception is caught and wrapped again, etc.
The output of this method is consistent across JDK versions.
Note that this is the opposite order to the JDK1.4 display.
The method is equivalent to
printStackTrace
for throwables
that don't have nested causes.
throwable
- the throwable to output, may be nullstream
- the stream to output to, may not be null
printRootCauseStackTrace
public static void printRootCauseStackTrace(Throwable throwable,
PrintWriter writer)
Prints a compact stack trace for the root cause of a throwable.
The compact stack trace starts with the root cause and prints
stack frames up to the place where it was caught and wrapped.
Then it prints the wrapped exception and continues with stack frames
until the wrapper exception is caught and wrapped again, etc.
The output of this method is consistent across JDK versions.
Note that this is the opposite order to the JDK1.4 display.
The method is equivalent to
printStackTrace
for throwables
that don't have nested causes.
throwable
- the throwable to output, may be nullwriter
- the writer to output to, may not be null
removeCauseMethodName
public static void removeCauseMethodName(String methodName)
Removes from the list of method names used in the search for Throwable
objects.
methodName
- the methodName to remove from the list, null
and empty strings are ignored
removeCommonFrames
public static void removeCommonFrames(List causeFrames,
List wrapperFrames)
Removes common frames from the cause trace given the two stack traces.
causeFrames
- stack trace of a cause throwablewrapperFrames
- stack trace of a wrapper throwable
setCause
public static boolean setCause(Throwable target,
Throwable cause)
Sets the cause of a
Throwable
using introspection, allowing
source code compatibility between pre-1.4 and post-1.4 Java releases.
The typical use of this method is inside a constructor as in
the following example:
import org.apache.commons.lang.exception.ExceptionUtils;
public class MyException extends Exception {
public MyException(String msg) {
super(msg);
}
public MyException(String msg, Throwable cause) {
super(msg);
ExceptionUtils.setCause(this, cause);
}
}
target
- the target Throwable
cause
- the Throwable
to set in the target
- a
true
if the target has been modified