seqnum

Class SequenceNumber

java.lang.Object

seqnum.SequenceNumber

public class SequenceNumber
extends Object

A simple implementation of a Sequence Number Generator. Numbers are unique and monotonically incremented in the domain determined by key. This is a simple implementation intended to demonstrate the concept. It may not scale well in the face of a large number of concurrent accesses. Use the KVStore instance name, host and port for running this program:

 java seqnum.SequenceNumber -store <instance name> \
                            -host  <host name>     \
                            -port  <port number>
 

For all examples the default instance name is kvstore, the default host name is localhost and the default port number is 5000. These defaults match the defaults for running kvlite, so the simplest way to run the examples along with kvlite is to omit all parameters.

Constructor Summary

Constructors

Constructor and Description
SequenceNumber(KVStore store, Key key, int noOfRetries, long initialValue) Creates an instance of the sequence number generator.

Method Summary

Methods

Modifier and Type	Method and Description
long	incrementAndGet() Returns the next number in the sequence after it synchronizes with the store, making a maximum of noOfRetries atempts. There are three possible outcomes when calling this method: - the next number in the sequence is returned. - the maximum number of retries is reached for trying to synchronize with the store and a RuntimeException is thrown - other exception if thrown by the store
static void	main(String[] args)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SequenceNumber

public SequenceNumber(KVStore store,
              Key key,
              int noOfRetries,
              long initialValue)

Creates an instance of the sequence number generator.

Parameters:

store - The store name.

key - The key determining the domain of the sequence

noOfRetries - The number of attempts to synchronize with the store

initialValue - The starting value of the sequence (the first value returned will be an increment of this one.

Method Detail

incrementAndGet

public long incrementAndGet()

Returns the next number in the sequence after it synchronizes with the store, making a maximum of noOfRetries atempts.
There are three possible outcomes when calling this method:
- the next number in the sequence is returned.
- the maximum number of retries is reached for trying to synchronize with the store and a RuntimeException is thrown
- other exception if thrown by the store

Returns:

the next number in the sequence

Throws:

java.lang.RuntimeException, - oracle.kv.DurabilityException oracle.kv.RequestTimeoutException oracle.kv.FaultException oracle.kv.ConsistencyException

main

public static void main(String[] args)