Harden ReferenceConsistencyChecker against invalid bundle contexts

[unic]

Harden ReferenceConsistencyChecker against invalid bundle contexts

[olaf-otto]

Ii would be interesting to know how the bundle context became invalid in the first place... However, the consistency checker must be hardened regardless.

[olaf-otto]

I've taken a look at the felix bundle context implementation to better understand how this happens. First of, this only happens on very old version of Felix (e.g. those shipped with CQ 5.3). It seems to me that this is a felix-internal issue, perhaps because the NEBA bundle is a fragment. Here is the code excerpt from [1]:

353    private void More ...checkValidity()
354    {
355        if (m_valid)
356        {
357            switch (m_bundle.getState())
358            {
359                case Bundle.ACTIVE:
360                case Bundle.STARTING:
361                case Bundle.STOPPING:
362                    return;
363            }
364        }
365
366        throw new IllegalStateException("Invalid BundleContext.");
367    }

Unfortunately, the exception does not tell what the unexpected state is.

[1] http://grepcode.com/file/repo1.maven.org/maven2/org.apache.felix/org.apache.felix.framework/2.0.5/org/apache/felix/framework/BundleContextImpl.java#BundleContextImpl.checkValidity%28%29

[olaf-otto]

After some analysis, I have come to the conclusion that the reference checker itself may be discarded due to an earlier architecture change.

When a bundle is stopped or fails, the ContextShutdownHandler removes all data related to the bundle from all registries. Consequently, it is safe to store a reference to the source bundle in the OsgiBeanSource. This makes it possible to simply check the validity there - which is also much better from an OO point of view:

Before:

consistencyChecker.isValid(source)

After:

source.isValid();

I'll put this on a feature branch.

[olaf-otto]

Done - merged pull request.