Package org.linuxforhealth.fhir.persistence.util

Class PartitionedSequentialKey

java.lang.Object

org.linuxforhealth.fhir.persistence.util.PartitionedSequentialKey

public class PartitionedSequentialKey
extends java.lang.Object

A key which contains partition, tstamp and identifier values. This key can be used to track changes being stored in a database. The partition value is used to distribute the keyspace in a partitioned datastore (like Cassandra). This means that jobs needing to scan the keys will need to scan each of the partitions, but this is useful because it's easy to parallelize. The tstamp field is simply the current UTC time. This creates a timeline which can be used to scan records in approximate time-order. Because this is not unique, algorithms such as reconciliation (looking for payloads stored in COS which aren't in the RDBMS) can only checkpoint to the tstamp level, not an individual key. This is OK, because restart from a checkpoint will be rare, and there should be relatively few keys sharing the same tstamp (assuming millisecond accuracy). The identifier is a random UUID and can be assumed to be globally unique.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PartitionedSequentialKey(int partition, long tstamp, java.lang.String resourceType, java.lang.String logicalId, int version)	Protected constructor.

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object obj)
static PartitionedSequentialKey	generateKey(java.lang.String resourceType, java.lang.String logicalId, int version)	Generate a new instance of PartitionedSequentialKey.
java.lang.String	getLogicalId()
int	getPartition()
java.lang.String	getResourceType()
long	getTstamp()
int	getVersion()
int	hashCode()

Methods inherited from class java.lang.Object

clone, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PartitionedSequentialKey

protected PartitionedSequentialKey(int partition,
                                   long tstamp,
                                   java.lang.String resourceType,
                                   java.lang.String logicalId,
                                   int version)

Protected constructor.

Parameters:

partition -

tstamp -

identifier -

Method Detail

generateKey

public static PartitionedSequentialKey generateKey(java.lang.String resourceType,
                                                   java.lang.String logicalId,
                                                   int version)

Generate a new instance of PartitionedSequentialKey.

Returns:

getPartition

public int getPartition()

Returns:

the partition

getTstamp

public long getTstamp()

Returns:

the tstamp

getResourceType

public java.lang.String getResourceType()

Returns:

the resourceType

getLogicalId

public java.lang.String getLogicalId()

Returns:

the logicalId

getVersion

public int getVersion()

Returns:

the version

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object