Package com.linecorp.armeria.common.util

Class Exceptions

java.lang.Object

com.linecorp.armeria.common.util.Exceptions

public final class Exceptions
extends Object

Provides methods that are useful for handling exceptions.

Method Summary

Modifier and Type	Method	Description
static <T extends Throwable> T	clearTrace(T exception)	Empties the stack trace of the specified exception.
static boolean	isExpected(Throwable cause)	Returns true if the specified exception is expected to occur in well-known circumstances.
static boolean	isStreamCancelling(Throwable cause)	Returns true if the specified exception will cancel the current request or response stream.
static void	logIfUnexpected(Logger logger, Channel ch, SessionProtocol protocol, String debugData, Throwable cause)	Logs the specified exception if it is unexpected.
static void	logIfUnexpected(Logger logger, Channel ch, SessionProtocol protocol, Throwable cause)	Logs the specified exception if it is unexpected.
static void	logIfUnexpected(Logger logger, Channel ch, String debugData, Throwable cause)	Logs the specified exception if it is unexpected.
static void	logIfUnexpected(Logger logger, Channel ch, Throwable cause)	Logs the specified exception if it is unexpected.
static Throwable	peel(Throwable throwable)	Returns the cause of the specified throwable peeling it recursively, if it is one of the CompletionException, ExecutionException, InvocationTargetException or ExceptionInInitializerError.
static void	throwIfFatal(Throwable t)	Throws a particular Throwable only if it belongs to a set of "fatal" error varieties.
static <T> T	throwUnsafely(Throwable cause)	Throws the specified exception violating the throws clause of the enclosing method.
static String	traceText(Throwable exception)	Converts the stack trace of the specified exception into a String.

Methods inherited from class java.lang.Object

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

Method Details

logIfUnexpected

public static void logIfUnexpected(Logger logger, Channel ch, Throwable cause)

Logs the specified exception if it is unexpected.

logIfUnexpected

public static void logIfUnexpected(Logger logger, Channel ch, String debugData, Throwable cause)

Logs the specified exception if it is unexpected.

logIfUnexpected

public static void logIfUnexpected(Logger logger, Channel ch, @Nullable SessionProtocol protocol, Throwable cause)

Logs the specified exception if it is unexpected.

logIfUnexpected

public static void logIfUnexpected(Logger logger, Channel ch, @Nullable SessionProtocol protocol, String debugData, Throwable cause)

Logs the specified exception if it is unexpected.

isExpected

public static boolean isExpected(Throwable cause)

Returns true if the specified exception is expected to occur in well-known circumstances.

• ClosedChannelException
• ClosedSessionException
• IOException - 'Connection reset/closed/aborted by peer'
• 'Broken pipe'
• Http2Exception - 'Stream closed'
• SSLException - 'SSLEngine closed already'

See Also:

Flags.verboseSocketExceptions()

isStreamCancelling

public static boolean isStreamCancelling(Throwable cause)

Returns true if the specified exception will cancel the current request or response stream.

clearTrace

public static <T extends Throwable> T clearTrace(T exception)

Empties the stack trace of the specified exception.

throwUnsafely

public static <T> T throwUnsafely(Throwable cause)

Throws the specified exception violating the throws clause of the enclosing method. This method is useful when you need to rethrow a checked exception in Function, Consumer, Supplier and Runnable, only if you are sure that the rethrown exception will be handled as a Throwable or an Exception. For example:

 CompletableFuture.supplyAsync(() -> {
     try (FileInputStream fin = new FileInputStream(...)) {
         ....
         return someValue;
     } catch (IOException e) {
         // 'throw e;' won't work because Runnable.run() does not allow any checked exceptions.
         return Exceptions.throwUnsafely(e);
     }
 }).exceptionally(CompletionActions::log);
 

Returns:

This method never returns because it always throws an exception. However, combined with an arbitrary return clause, you can terminate any non-void function with a single statement. e.g. return Exceptions.throwUnsafely(...); vs. Exceptions.throwUnsafely(...); return null;

throwIfFatal

public static void throwIfFatal(Throwable t)

Throws a particular Throwable only if it belongs to a set of "fatal" error varieties. These varieties are as follows:

• VirtualMachineError
• ThreadDeath
• LinkageError

This can be useful if you are writing an operator that calls user-supplied code, and you want to notify subscribers of errors encountered in that code by calling their onError methods, but only if the errors are not so catastrophic that such a call would be futile, in which case you simply want to rethrow the error.

Parameters:

t - the Throwable to test and perhaps throw

See Also:

RxJava: StackOverflowError is swallowed (Issue #748)

peel

public static Throwable peel(Throwable throwable)

Returns the cause of the specified throwable peeling it recursively, if it is one of the CompletionException, ExecutionException, InvocationTargetException or ExceptionInInitializerError. Otherwise returns the throwable.

traceText

public static String traceText(Throwable exception)

Converts the stack trace of the specified exception into a String. This method always uses '\n' as a line delimiter, unlike Throwable.printStackTrace(PrintWriter) or Throwables.getStackTraceAsString(Throwable).