o != arg0
is the same as !(o == (arg0))
.
o != arg0
is the same as !(o == (arg0))
.
the object to compare against this object for dis-equality.
false
if the receiver object is equivalent to the argument; true
otherwise.
o == arg0
is the same as if (o eq null) arg0 eq null else o.equals(arg0)
.
o == arg0
is the same as if (o eq null) arg0 eq null else o.equals(arg0)
.
the object to compare against this object for equality.
true
if the receiver object is equivalent to the argument; false
otherwise.
o == arg0
is the same as o.equals(arg0)
.
o == arg0
is the same as o.equals(arg0)
.
the object to compare against this object for equality.
true
if the receiver object is equivalent to the argument; false
otherwise.
This method is used to cast the receiver object to be of type T0
.
This method is used to cast the receiver object to be of type T0
.
Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression1.asInstanceOf[String]
will throw a ClassCastException
at runtime, while the expressionList(1).asInstanceOf[List[String]]
will not. In the latter example, because the type argument is erased as
part of compilation it is not possible to check whether the contents of the list are of the requested typed.
the receiver object.
This method creates and returns a copy of the receiver object.
This method creates and returns a copy of the receiver object.
The default implementation of the clone
method is platform dependent.
a copy of the receiver object.
This method is used to test whether the argument (arg0
) is a reference to the
receiver object (this
).
This method is used to test whether the argument (arg0
) is a reference to the
receiver object (this
).
The eq
method implements an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation] on
non-null instances of AnyRef
:
* It is reflexive: for any non-null instance x
of type AnyRef
, x.eq(x)
returns true
.
* It is symmetric: for any non-null instances x
and y
of type AnyRef
, x.eq(y)
returns true
if and
only if y.eq(x)
returns true
.
* It is transitive: for any non-null instances x
, y
, and z
of type AnyRef
if x.eq(y)
returns true
and y.eq(z)
returns true
, then x.eq(z)
returns true
.
Additionally, the eq
method has three other properties.
* It is consistent: for any non-null instances x
and y
of type AnyRef
, multiple invocations of
x.eq(y)
consistently returns true
or consistently returns false
.
* For any non-null instance x
of type AnyRef
, x.eq(null)
and null.eq(x)
returns false
.
* null.eq(null)
returns true
.
When overriding the equals
or hashCode
methods, it is important to ensure that their behavior is
consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2
), they
should be equal to each other (o1 == o2
) and they should hash to the same value (o1.hashCode == o2.hashCode
).
the object to compare against this object for reference equality.
true
if the argument is a reference to the receiver object; false
otherwise.
This method is used to compare the receiver object (this
) with the argument object (arg0
) for equivalence.
This method is used to compare the receiver object (this
) with the argument object (arg0
) for equivalence.
The default implementations of this method is an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence
relation]:
* It is reflexive: for any instance x
of type Any
, x.equals(x)
should return true
.
* It is symmetric: for any instances x
and y
of type Any
, x.equals(y)
should return true
if and
only if y.equals(x)
returns true
.
* It is transitive: for any instances x
, y
, and z
of type AnyRef
if x.equals(y)
returns true
and
y.equals(z)
returns true
, then x.equals(z)
should return true
.
If you override this method, you should verify that your implementation remains an equivalence relation.
Additionally, when overriding this method it is often necessary to override hashCode
to ensure that objects
that are "equal" (o1.equals(o2)
returns true
) hash to the same
scala.Int
(o1.hashCode.equals(o2.hashCode)
).
the object to compare against this object for equality.
true
if the receiver object is equivalent to the argument; false
otherwise.
This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.
This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.
The details of when and if the finalize
method are invoked, as well as the interaction between finalize
and non-local returns and exceptions, are all platform dependent.
Returns a representation that corresponds to the dynamic class of the receiver object.
Returns a representation that corresponds to the dynamic class of the receiver object.
The nature of the representation is platform dependent.
a representation that corresponds to the dynamic class of the receiver object.
Returns a hash code value for the object.
Returns a hash code value for the object.
The default hashing algorithm is platform dependent.
Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)
) yet
not be equal (o1.equals(o2)
returns false
). A degenerate implementation could always return 0
.
However, it is required that if two objects are equal (o1.equals(o2)
returns true
) that they have
identical hash codes (o1.hashCode.equals(o2.hashCode)
). Therefore, when overriding this method, be sure
to verify that the behavior is consistent with the equals
method.
the hash code value for the object.
Returns true if this broker is the current controller.
Returns true if this broker is the current controller.
This method is used to test whether the dynamic type of the receiver object is T0
.
This method is used to test whether the dynamic type of the receiver object is T0
.
Note that the test result of the test is modulo Scala's erasure semantics. Therefore the expression1.isInstanceOf[String]
will return false
, while the expression List(1).isInstanceOf[List[String]]
will
return true
. In the latter example, because the type argument is erased as part of compilation it is not
possible to check whether the contents of the list are of the requested typed.
true
if the receiver object is an instance of erasure of type T0
; false
otherwise.
o.ne(arg0)
is the same as !(o.eq(arg0))
.
o.ne(arg0)
is the same as !(o.eq(arg0))
.
the object to compare against this object for reference dis-equality.
false
if the argument is not a reference to the receiver object; true
otherwise.
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
This callback is invoked by the replica state machine's broker change listener with the list of failed brokers as input.
This callback is invoked by the replica state machine's broker change listener with the list of failed brokers as input. It does the following - 1. Mark partitions with dead leaders as offline 2. Triggers the OnlinePartition state change for all new/offline partitions 3. Invokes the OfflineReplica state change on the input list of newly started brokers
Note that we don't need to refresh the leader/isr cache for all topic/partitions at this point. This is because the partition state machine will refresh our cache for us when performing leader election for all new/offline partitions coming online.
This callback is invoked by the replica state machine's broker change listener, with the list of newly started brokers as input.
This callback is invoked by the replica state machine's broker change listener, with the list of newly started brokers as input. It does the following - 1. Triggers the OnlinePartition state change for all new/offline partitions 2. It checks whether there are reassigned replicas assigned to any newly started brokers. If so, it performs the reassignment logic for each topic/partition.
Note that we don't need to refresh the leader/isr cache for all topic/partitions at this point for two reasons: 1. The partition state machine, when triggering online state change, will refresh leader and ISR for only those partitions currently new or offline (rather than every partition this controller is aware of) 2. Even if we do refresh the cache, there is no guarantee that by the time the leader and ISR request reaches every broker that it is still valid. Brokers check the leader epoch to determine validity of the request.
This callback is invoked by the zookeeper leader elector on electing the current broker as the new controller.
This callback is invoked by the zookeeper leader elector on electing the current broker as the new controller. It does the following things on the become-controller state change - 1. Register controller epoch changed listener 2. Increments the controller epoch 3. Initializes the controller's context object that holds cache objects for current topics, live brokers and leaders for all existing partitions. 4. Starts the controller's channel manager 5. Starts the replica state machine 6. Starts the partition state machine If it encounters any unexpected exception/error while becoming controller, it resigns as the current controller. This ensures another controller election will be triggered and there will always be an actively serving controller
This callback is invoked by the zookeeper leader elector when the current broker resigns as the controller.
This callback is invoked by the zookeeper leader elector when the current broker resigns as the controller. This is required to clean up internal controller data structures
This callback is invoked by the topic change callback with the list of failed brokers as input.
This callback is invoked by the topic change callback with the list of failed brokers as input. It does the following - 1. Move the newly created partitions to the NewPartition state 2. Move the newly created partitions from NewPartition->OnlinePartition state
This callback is invoked by the partition state machine's topic change listener with the list of new topics and partitions as input.
This callback is invoked by the partition state machine's topic change listener with the list of new topics and partitions as input. It does the following - 1. Registers partition change listener. This is not required until KAFKA-347 2. Invokes the new partition callback 3. Send metadata request with the new topic to all brokers so they allow requests for that topic to be served
This callback is invoked by the reassigned partitions listener.
This callback is invoked by the reassigned partitions listener. When an admin command initiates a partition reassignment, it creates the /admin/reassign_partitions path that triggers the zookeeper listener. Reassigning replicas for a partition goes through a few steps listed in the code. RAR = Reassigned replicas OAR = Original list of replicas for partition AR = current assigned replicas
1. Update AR in ZK with OAR + RAR. 2. Send LeaderAndIsr request to every replica in OAR + RAR (with AR as OAR + RAR). We do this by forcing an update of the leader epoch in zookeeper. 3. Start new replicas RAR - OAR by moving replicas in RAR - OAR to NewReplica state. 4. Wait until all replicas in RAR are in sync with the leader. 5 Move all replicas in RAR to OnlineReplica state. 6. Set AR to RAR in memory. 7. If the leader is not in RAR, elect a new leader from RAR. If new leader needs to be elected from RAR, a LeaderAndIsr will be sent. If not, then leader epoch will be incremented in zookeeper and a LeaderAndIsr request will be sent. In any case, the LeaderAndIsr request will have AR = RAR. This will prevent the leader from adding any replica in RAR - OAR back in the isr. 8. Move all replicas in OAR - RAR to OfflineReplica state. As part of OfflineReplica state change, we shrink the isr to remove OAR - RAR in zookeeper and sent a LeaderAndIsr ONLY to the Leader to notify it of the shrunk isr. After that, we send a StopReplica (delete = false) to the replicas in OAR - RAR. 9. Move all replicas in OAR - RAR to NonExistentReplica state. This will send a StopReplica (delete = false) to the replicas in OAR - RAR to physically delete the replicas on disk. 10. Update AR in ZK with RAR. 11. Update the /admin/reassign_partitions path in ZK to remove this partition. 12. After electing leader, the replicas and isr information changes. So resend the update metadata request to every broker.
For example, if OAR = {1, 2, 3} and RAR = {4,5,6}, the values in the assigned replica (AR) and leader/isr path in ZK may go through the following transition. AR leader/isr {1,2,3} 1/{1,2,3} (initial state) {1,2,3,4,5,6} 1/{1,2,3} (step 2) {1,2,3,4,5,6} 1/{1,2,3,4,5,6} (step 4) {1,2,3,4,5,6} 4/{1,2,3,4,5,6} (step 7) {1,2,3,4,5,6} 4/{4,5,6} (step 8) {4,5,6} 4/{4,5,6} (step 10)
Note that we have to update AR in ZK with RAR last since it's the only place where we store OAR persistently. This way, if the controller crashes before that step, we can still recover.
Removes a given partition replica from the ISR; if it is not the current leader and there are sufficient remaining replicas in ISR.
Removes a given partition replica from the ISR; if it is not the current leader and there are sufficient remaining replicas in ISR.
topic
partition
replica Id
the new leaderAndIsr (with the replica removed if it was present), or None if leaderAndIsr is empty.
Send the leader information for selected partitions to selected brokers so that they can correctly respond to metadata requests
Send the leader information for selected partitions to selected brokers so that they can correctly respond to metadata requests
The brokers that the update metadata request should be sent to
Invoked when the controller module of a Kafka server is shutting down.
Invoked when the controller module of a Kafka server is shutting down. If the broker was the current controller, it shuts down the partition and replica state machines. If not, those are a no-op. In addition to that, it also shuts down the controller channel manager, if one exists (i.e. if it was the current controller)
On clean shutdown, the controller first determines the partitions that the shutting down broker leads, and moves leadership of those partitions to another broker that is in that partition's ISR.
On clean shutdown, the controller first determines the partitions that the shutting down broker leads, and moves leadership of those partitions to another broker that is in that partition's ISR.
Id of the broker to shutdown.
The number of partitions that the broker still leads.
Invoked when the controller module of a Kafka server is started up.
Invoked when the controller module of a Kafka server is started up. This does not assume that the current broker is the controller. It merely registers the session expiration listener and starts the controller leader elector
Returns a string representation of the object.
Returns a string representation of the object.
The default representation is platform dependent.
a string representation of the object.