@InterfaceAudience.Private public class EnvironmentEdgeManager extends Object
EnvironmentEdge, then defer to the delegate on invocation.
EnvironmentEdgeManager). The idea is to have a central place where time can be assigned in HBase. That makes it easier to inject different implementations of time. The default environment edge is the Java Current Time in millis. The environment edge manager class is designed to be able to plug in a new implementation of time by simply injecting an implementation of
Problems with Environment Edge:
1. One of the major problems is the side effects of injecting an Environment Edge into Environment Edge Manager.
For example, A test could inject an edge to fast forward time in order to avoid thread sleep to save time, but it could trigger a premature waking up of another thread waiting on a condition dependent on time lapse, which could potentially affect the normal working of the system leading to failure of tests.
2. Every test should ensure it is setting the Environment Edge it needs for the test to perform in an expected way. Because another test which might have run before the current test could have injected its own custom Environment Edge which may not be applicable to this test. This is still solvable but the problem is that the tests can run in parallel leading to different combinations of environment edges being injected causing unexpected results.
3. Another important issue with respect to injecting time through Environment Edge is that the milliseconds unit of time is ingrained throughout the codebase in the form of hardcoded sleep time or timeouts that any change of time unit or making it fast or slow can potentially trigger unexpected failures due to timeout or unintended flow of execution.
DefaultEnvironmentEdgeis being used, whose implementation of time returns the
System.currentTimeMillis(). It is advised not to inject any other
|Modifier and Type||Method and Description|
Defers to the delegate and calls the
Retrieves the singleton instance of the
Injects the given edge such that it becomes the managed entity.
Resets the managed instance to the default instance:
public static EnvironmentEdge getDelegate()
EnvironmentEdgethat is being managed.
public static void reset()
public static void injectEdge(EnvironmentEdge edge)
edge- the new edge.
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