Package org.apache.sis.util

Class Exceptions

Object

Static

Exceptions

public final class Exceptions
extends Static

Static methods working with Exception instances.

Since:

0.3

Defined in the sis-utility module

Method Summary

Modifier and Type	Method	Description
static String	format­Chained­Messages(Locale locale, String header, Throwable cause)	Returns a string which contain the given message on the first line, followed by the localized message of the given exception on the next line.
static String	get­Localized­Message(Throwable exception, Locale locale)	Returns the message of the given exception, localized in the given locale if possible.
static boolean	message­Equals(Throwable first, Throwable second)	Returns true if the given exceptions are of the same class and contains the same message.
static <T extends Throwable> T	set­Message(T exception, String message, boolean append)	Returns an exception of the same kind and with the same stack trace than the given exception, but with a different message.
static Exception	unwrap(Exception exception)	If the given exception is a wrapper for another exception, returns the unwrapped exception.

Methods inherited from class Object

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

Method Details

getLocalizedMessage

public static String getLocalizedMessage(Throwable exception,
 Locale locale)

Returns the message of the given exception, localized in the given locale if possible. Some exceptions created by SIS can format a message in different locales. This method returns such localized message if possible, or fallback on the standard JDK methods otherwise. More specifically:

• If the given exception is null, then this method returns null.
• Otherwise if the given locale is null, then this method returns Throwable.get­Message(). This is consistent with the Localized policy saying that null locale stands for "unlocalized" message (usually in English) or message in the JVM default locale.
• Otherwise if the given exception is an instance of Localized­Exception providing a non-null international message, then this method returns the result of International­String.to­String(Locale).
• Otherwise this method returns Throwable.get­Localized­Message().

Parameters:

exception - the exception from which to get the localize message, or null.

locale - the preferred locale for the message, or null for the JVM default locale. This locale is honored on a best-effort basis only.

Returns:

the message in the given locale if possible, or null if the exception argument was null or if the exception does not contain a message.

See Also:

• Localized­Exception.get­Localized­Message()

setMessage

public static <T extends Throwable> T setMessage(T exception,
 String message,
 boolean append)

Returns an exception of the same kind and with the same stack trace than the given exception, but with a different message. This method simulates the functionality that we would have if Throwable defined a set­Message(String) method. We use this method when an external library throws an exception of the right type, but with too few details.

This method tries to create a new exception using reflection. The exception class needs to provide a public constructor expecting a single String argument. If the exception class does not provide such constructor, then the given exception is returned unchanged.

Type Parameters:

T - the type of the exception.

Parameters:

exception - the exception to copy with a different message.

message - the message to set in the exception to be returned.

append - if true, the existing message in the original exception (if any) will be happened after the provided message.

Returns:

a new exception with the given message, or the given exception if the exception class does not provide public Exception(String) constructor.

messageEquals

public static boolean messageEquals(Throwable first,
 Throwable second)

Returns true if the given exceptions are of the same class and contains the same message. This method does not compare the stack trace, cause or suppressed exceptions.

Parameters:

first - the first exception, or null.

second - the second exception, or null.

Returns:

true if both exceptions are null, or both exceptions are non-null, of the same class and with the same message.

Since:

1.0

formatChainedMessages

public static String formatChainedMessages(Locale locale,
 String header,
 Throwable cause)

Returns a string which contain the given message on the first line, followed by the localized message of the given exception on the next line. If the exception has a causes, then the class name and the localized message of the cause are formatted on the next line and the process is repeated for the whole cause chain, omitting duplicated messages.

SQLException is handled especially in order to process the next exception instead of the cause.

This method does not format the stack trace.

Parameters:

locale - the preferred locale for the exception message, or null.

header - the message to insert on the first line, or null if none.

cause - the exception, or null if none.

Returns:

the formatted message, or null if both the header was null and no exception provide a message.

unwrap

public static Exception unwrap(Exception exception)

If the given exception is a wrapper for another exception, returns the unwrapped exception. Otherwise returns the given argument unchanged. An exception is considered a wrapper if:

• It is an instance of Invocation­Target­Exception (could be wrapping anything).
• It is an instance of Execution­Exception (could be wrapping anything).
• It is an instance of Backing­Store­Exception (typically wrapping a checked exception).
• It is an instance of Unchecked­IOException (wrapping a IOException).
• It is an instance of Directory­Iterator­Exception (wrapping a IOException).
• It is a parent type of the cause. For example some JDBC drivers wrap SQLException in other SQLException without additional information.

Note: Privileged­Action­Exception is also a wrapper exception, but is not included in above list because it is used in very specific contexts.

This method uses only the exception class and the absence of suppressed exceptions as criterion; it does not verify if the exception messages are the same.

Parameters:

exception - the exception to unwrap (may be null.

Returns:

the unwrapped exception (may be the given argument itself).

Since:

0.8