com.hp.util.proxy

Class ThrowableRecorderProxy<T>

java.lang.Object

com.hp.util.proxy.ThrowableRecorderProxy<T>

Type Parameters:

T - type of the subject or delegate to create a proxy for

All Implemented Interfaces:

Proxy<T>

public final class ThrowableRecorderProxy<T>
extends Object
implements Proxy<T>

Proxy to verify whether errors are thrown in the context of a different thread.

Note: This proxy does not hide problems, the errors are recorded but they still are thrown.

One application if this class is in unit test in multi-threading environments:

If expectations (like listener notifications) are carried out in a different thread then mocking has the following implications:

1. If an unexpected method invocation happens, the test won't fail because unexpected invocations throw an exception as soon as they are called, but this exception will be caught in a different thread.
2. If an expected method invocation does not happen, the test will fail in EasyMock.verify(Object...) as expected.

This class is used to to solve the first problem: "The test does not fail if an exception happens in a different thread".

Note that if the thread scheduling is controlled (A thread pool is used to submit or schedule a thread) then a Future could be used to get the exception in the context of the calling thread. This class should be used in integration test where threads cannot be controlled: For example when a framework is used and such framework notifies listener in a different thread and the notifications need to be asserted in the test.

Another application of this class could be logging the errors if the thread were this are thrown does not catch them. Otherwise they will just appear in the console.

Author:

Fabiel Zuniga

See Also:

DynamicProxy

Constructor Summary

Constructors

Constructor and Description
ThrowableRecorderProxy()

Method Summary

Methods

Modifier and Type	Method and Description
List<Throwable>	getRecords() Returns the throwables that has been thrown.
Object	invoke(T subject, Method method, Object[] args) Processes a method invocation on a proxy instance and returns the result.
List<Throwable>	popRecords() Clears and returns the throwables that has been thrown.
void	verify() Verifies no errors were thrown.

Methods inherited from class java.lang.Object

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

Constructor Detail

ThrowableRecorderProxy

public ThrowableRecorderProxy()

Method Detail

invoke

public Object invoke(T subject,
            Method method,
            Object[] args)
              throws Throwable

Description copied from interface: Proxy

Processes a method invocation on a proxy instance and returns the result.

Specified by:

invoke in interface Proxy<T>

Parameters:

subject - subject or delegate for which the proxy was created for

method - the method been invoked

args - the method arguments

Returns:

the invocation returned value

Throws:

Throwable - if an error occurs

getRecords

public List<Throwable> getRecords()

Returns the throwables that has been thrown.

Returns:

the records

popRecords

public List<Throwable> popRecords()

Clears and returns the throwables that has been thrown.

Returns:

the records

verify

public void verify()
            throws Throwable

Verifies no errors were thrown. If error was thrown, the first one is is re-thrown by this method. This is a convenient method to use during unit test to make the test fail.

Throws:

Throwable - first recorded error if any