dk.rode.thesis.singleton
Class SingletonException

java.lang.Object
  java.lang.Throwable
      java.lang.Exception
          java.lang.RuntimeException
              dk.rode.thesis.singleton.SingletonException

All Implemented Interfaces:

Serializable

public class SingletonException
extends RuntimeException

A singleton exception is thrown in case a given type cannot be determined to be a singleton type when requested from a given registry or in case a singleton instance cannot be acquired from a registry.

Implementation notes:
Declared as a runtime exception because ordinary use of singletons and singleton registries are assumed to be correct by the context using them. The context, for example, should never test for a null return value from a registry, because either the singleton instance exist or it does not; a null value does not make any sense, and would constitute a poor design decision. Hence, in the general case, the context should not have to worry about checked exceptions as they would never be thrown.

The singleton creation could fail, of cause, but that is of no concern to the registry as it will simply re-throw such errors wrapped in this exception type.

Author:

Gunni Rode / rode.dk

See Also:

Serialized Form

Field Summary

(package private) static long

serialVersionUID Serial version id.

Constructor Summary

SingletonException()
No-arg constructor.

SingletonException(Class<?> type)
Constructor.

SingletonException(String message)
Constructor.

SingletonException(Throwable cause)
Constructor.

Method Summary

Methods inherited from class java.lang.Throwable

fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

static final long serialVersionUID

Serial version id.

See Also:

Constant Field Values

Constructor Detail

SingletonException

public SingletonException()

No-arg constructor.

SingletonException

public SingletonException(Class<?> type)

Constructor.

Parameters:

type - The faulting type; can be null.

SingletonException

public SingletonException(String message)

Constructor.

Parameters:

message - The detail message; can be null.

SingletonException

public SingletonException(Throwable cause)

Constructor.

Parameters:

cause - The causing throwable; can be null.