'bypass' logic case by case
Changes Coprocessor ObserverContext 'bypass' semantic. We flip the
default so bypass is NOT supported on Observer invocations; only a
couple of preXXX methods in RegionObserver allow it: e.g. preGet
and prePut but not preFlush, etc. Everywhere else, we throw
a DoesNotSupportBypassException if a Coprocessor Observer
tries to invoke bypass. Master Observers can no longer stop
or change move, split, assign, create table, etc.
Ditto on complete, the mechanism that allowed a Coprocessor
rule that all subsequent Coprocessors are skipped in an
invocation chain; now, complete is only available to
bypassable methods (and Coprocessors will get an exception if
they try to 'complete' when it is not allowed).
See javadoc for whether a Coprocessor Observer method supports
'bypass'. If no mention, 'bypass' is NOT supported.
M hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java
Added passing of 'bypassable' (and 'completable') and default 'result' argument to
the Operation constructors rather than pass the excecution engine as parameters.
Makes it so can clean up RegionObserverHost and make the calling
clearer regards what is going on.
Methods that support 'bypass' must set this flag on the Observer.
M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
Refactoring in here is minor. A few methods that used support bypass
no longer do so removed the check and the need of an if/else meant a
left-shift in some code.
M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
Ditto
M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionCoprocessorHost.java
In here label explicitly those methods that are bypassable.
Some changes to make sure we call the corresponding execOperation.
TestMasterObserver had a bunch of test of bypass method. All removed or
disabled.
TODO: What to do w/ the Scanner methods.