CentralizedServiceWorker (Apache Giraph Parent 1.4.0-SNAPSHOT API)

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

All Superinterfaces:

CentralizedService<I,V,E>, PartitionSplitInfo<I>

All Known Implementing Classes:

BspServiceWorker
```
public interface CentralizedServiceWorker<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable>
extends CentralizedService<I,V,E>, PartitionSplitInfo<I>
```
All workers should have access to this centralized service to execute the following methods.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`addressesAndPartitionsReceived(AddressesAndPartitionsWritable addressesAndPartitions)` Received addresses and partitions assignments from master.
`void`	`cleanup(FinishedSuperstepStats finishedSuperstepStats)` Clean up the service (no calls may be issued after this)
`void`	`closeZooKeeper()` Close zookeeper
`void`	`exchangeVertexPartitions(Collection<? extends PartitionOwner> masterSetPartitionOwners)` If desired by the user, vertex partitions are redistributed among workers according to the chosen WorkerGraphPartitioner.
`void`	`failureCleanup()` Operations that will be called if there is a failure by a worker.
`FinishedSuperstepStats`	`finishSuperstep(List<PartitionStats> partitionStatsList, GiraphTimerContext superstepTimerContext)` Worker is done with its portion of the superstep.
`WorkerAggregatorHandler`	`getAggregatorHandler()` Get worker aggregator handler
`GlobalStats`	`getGlobalStats()` Loads Global stats from zookeeper.
`GraphTaskManager<I,V,E>`	`getGraphTaskManager()` Get the GraphTaskManager that this service is using.
`WorkerInputSplitsHandler`	`getInputSplitsHandler()` Get input splits handler used during input
`int`	`getPartitionId(I vertexId)` Get the partition id that a vertex id would belong to.
`Iterable<? extends PartitionOwner>`	`getPartitionOwners()` Get all partition owners.
`PartitionStore<I,V,E>`	`getPartitionStore()` Get the partition store for this worker.
`ServerData<I,V,E>`	`getServerData()` Get server data
`SuperstepOutput<I,V,E>`	`getSuperstepOutput()` Get the superstep output class
`PartitionOwner`	`getVertexPartitionOwner(I vertexId)` Every client will need to get a partition owner from a vertex id so that they know which worker to sent the request to.
`WorkerClient<I,V,E>`	`getWorkerClient()` Get the worker client (for instantiating WorkerClientRequestProcessor instances.
`WorkerContext`	`getWorkerContext()` Get the worker context.
`WorkerInfo`	`getWorkerInfo()` Get the worker information
`WorkerObserver[]`	`getWorkerObservers()` Get the observers for this Worker.
`boolean`	`hasPartition(Integer partitionId)` Whether a partition with given id exists on this worker.
`VertexEdgeCount`	`loadCheckpoint(long superstep)` Load the vertices, edges, messages from the beginning of a superstep.
`void`	`prepareSuperstep()` Final preparation for superstep, called after startSuperstep and potential loading from checkpoint, right before the computation started TODO how to avoid this additional function
`FinishedSuperstepStats`	`setup()` Setup (must be called prior to any other function)
`Collection<? extends PartitionOwner>`	`startSuperstep()` Take all steps prior to actually beginning the computation of a superstep.
`void`	`storeCheckpoint()` Both the vertices and the messages need to be checkpointed in order for them to be used.
`void`	`storeCountersInZooKeeper(boolean allSuperstepsDone)` Store the counter values in the zookeeper after every superstep and also after all supersteps are done.

Methods inherited from interface org.apache.giraph.bsp.CentralizedService
getConfiguration, getJobProgressTracker, getMasterInfo, getRestartedSuperstep, getSuperstep, getWorkerInfoList

Methods inherited from interface org.apache.giraph.comm.messages.PartitionSplitInfo
getNextPartition, getPartitionIds, getPartitionVertexCount, putPartition, startIteration

- Method Detail
  - setup
```
FinishedSuperstepStats setup()
```
    Setup (must be called prior to any other function)
    
    Returns:
    
    Finished superstep stats for the input superstep
  - getWorkerInfo
```
WorkerInfo getWorkerInfo()
```
    Get the worker information
    
    Returns:
    
    Worker information
  - getWorkerClient
```
WorkerClient<I,V,E> getWorkerClient()
```
    Get the worker client (for instantiating WorkerClientRequestProcessor instances.
    
    Returns:
    
    Worker client
  - getWorkerContext
```
WorkerContext getWorkerContext()
```
    Get the worker context.
    
    Returns:
    
    worker's WorkerContext
  - getWorkerObservers
```
WorkerObserver[] getWorkerObservers()
```
    Get the observers for this Worker.
    
    Returns:
    
    array of WorkerObservers.
  - getPartitionStore
```
PartitionStore<I,V,E> getPartitionStore()
```
    Get the partition store for this worker. The partitions contain the vertices for this worker and can be used to run compute() for the vertices or do checkpointing.
    
    Returns:
    
    The partition store for this worker.
  - storeCheckpoint
```
void storeCheckpoint()
              throws IOException
```
    Both the vertices and the messages need to be checkpointed in order for them to be used. This is done after all messages have been delivered, but prior to a superstep starting.
    
    Throws:
    
    IOException
  - loadCheckpoint
```
VertexEdgeCount loadCheckpoint(long superstep)
                        throws IOException
```
    Load the vertices, edges, messages from the beginning of a superstep. Will load the vertex partitions as designated by the master and set the appropriate superstep.
    
    Parameters:
    
    superstep - which checkpoint to use
    
    Returns:
    
    Graph-wide vertex and edge counts
    
    Throws:
    
    IOException
  - startSuperstep
```
Collection<? extends PartitionOwner> startSuperstep()
```
    Take all steps prior to actually beginning the computation of a superstep.
    
    Returns:
    
    Collection of all the partition owners from the master for this superstep.
  - finishSuperstep
```
FinishedSuperstepStats finishSuperstep(List<PartitionStats> partitionStatsList,
                                       GiraphTimerContext superstepTimerContext)
```
    Worker is done with its portion of the superstep. Report the worker level statistics after the computation.
    
    Parameters:
    
    partitionStatsList - All the partition stats for this worker
    
    superstepTimerContext - superstep timer context only given when the function needs to stop the timer, otherwise null.
    
    Returns:
    
    Stats of the superstep completion
  - getPartitionId
```
int getPartitionId(I vertexId)
```
    Get the partition id that a vertex id would belong to.
    
    Specified by:
    
    getPartitionId in interface PartitionSplitInfo<I extends org.apache.hadoop.io.WritableComparable>
    
    Parameters:
    
    vertexId - Vertex id
    
    Returns:
    
    Partition id
  - hasPartition
```
boolean hasPartition(Integer partitionId)
```
    Whether a partition with given id exists on this worker.
    
    Parameters:
    
    partitionId - Partition id
    
    Returns:
    
    True iff this worker has the specified partition
  - getVertexPartitionOwner
```
PartitionOwner getVertexPartitionOwner(I vertexId)
```
    Every client will need to get a partition owner from a vertex id so that they know which worker to sent the request to.
    
    Parameters:
    
    vertexId - Vertex index to look for
    
    Returns:
    
    PartitionOnwer that should contain this vertex if it exists
  - getPartitionOwners
```
Iterable<? extends PartitionOwner> getPartitionOwners()
```
    Get all partition owners.
    
    Returns:
    
    Iterable through partition owners
  - exchangeVertexPartitions
```
void exchangeVertexPartitions(Collection<? extends PartitionOwner> masterSetPartitionOwners)
```
    If desired by the user, vertex partitions are redistributed among workers according to the chosen WorkerGraphPartitioner.
    
    Parameters:
    
    masterSetPartitionOwners - Partition owner info passed from the master.
  - getGraphTaskManager
```
GraphTaskManager<I,V,E> getGraphTaskManager()
```
    Get the GraphTaskManager that this service is using. Vertices need to know this.
    
    Returns:
    
    the GraphTaskManager instance for this compute node
  - failureCleanup
```
void failureCleanup()
```
    Operations that will be called if there is a failure by a worker.
  - getServerData
```
ServerData<I,V,E> getServerData()
```
    Get server data
    
    Returns:
    
    Server data
  - getAggregatorHandler
```
WorkerAggregatorHandler getAggregatorHandler()
```
    Get worker aggregator handler
    
    Returns:
    
    Worker aggregator handler
  - prepareSuperstep
```
void prepareSuperstep()
```
    Final preparation for superstep, called after startSuperstep and potential loading from checkpoint, right before the computation started TODO how to avoid this additional function
  - getSuperstepOutput
```
SuperstepOutput<I,V,E> getSuperstepOutput()
```
    Get the superstep output class
    
    Returns:
    
    SuperstepOutput
  - cleanup
```
void cleanup(FinishedSuperstepStats finishedSuperstepStats)
      throws IOException,
             InterruptedException
```
    Clean up the service (no calls may be issued after this)
    
    Parameters:
    
    finishedSuperstepStats - Finished supestep stats
    
    Throws:
    
    IOException
    
    InterruptedException
  - getGlobalStats
```
GlobalStats getGlobalStats()
```
    Loads Global stats from zookeeper.
    
    Returns:
    
    global stats stored in zookeeper for previous superstep.
  - getInputSplitsHandler
```
WorkerInputSplitsHandler getInputSplitsHandler()
```
    Get input splits handler used during input
    
    Returns:
    
    Input splits handler
  - addressesAndPartitionsReceived
```
void addressesAndPartitionsReceived(AddressesAndPartitionsWritable addressesAndPartitions)
```
    Received addresses and partitions assignments from master.
    
    Parameters:
    
    addressesAndPartitions - Addresses and partitions assignment
  - storeCountersInZooKeeper
```
void storeCountersInZooKeeper(boolean allSuperstepsDone)
```
    Store the counter values in the zookeeper after every superstep and also after all supersteps are done. This is called before closing the zookeeper. We need to call this method after calling cleanup on the worker, since some counters are updated during cleanup
    
    Parameters:
    
    allSuperstepsDone - boolean value whether all the supersteps are completed
  - closeZooKeeper
```
void closeZooKeeper()
```
    Close zookeeper

Interface CentralizedServiceWorker<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable>

Method Summary

Methods inherited from interface org.apache.giraph.bsp.CentralizedService

Methods inherited from interface org.apache.giraph.comm.messages.PartitionSplitInfo

Method Detail

setup

getWorkerInfo

getWorkerClient

getWorkerContext

getWorkerObservers

getPartitionStore

storeCheckpoint

loadCheckpoint

startSuperstep

finishSuperstep

getPartitionId

hasPartition

getVertexPartitionOwner

getPartitionOwners

exchangeVertexPartitions

getGraphTaskManager

failureCleanup

getServerData

getAggregatorHandler

prepareSuperstep

getSuperstepOutput

cleanup

getGlobalStats

getInputSplitsHandler

addressesAndPartitionsReceived

storeCountersInZooKeeper

closeZooKeeper