com.datastax.driver.core

Class ThreadLocalMonotonicTimestampGenerator

java.lang.Object

com.datastax.driver.core.AbstractMonotonicTimestampGenerator

com.datastax.driver.core.LoggingMonotonicTimestampGenerator

com.datastax.driver.core.ThreadLocalMonotonicTimestampGenerator

All Implemented Interfaces:

TimestampGenerator

public class ThreadLocalMonotonicTimestampGenerator
extends LoggingMonotonicTimestampGenerator

A timestamp generator that guarantees monotonically increasing timestamps on a per-thread basis, and logs warnings when timestamps drift in the future.

Beware that there is a risk of timestamp collision with this generator when accessed by more than one thread at a time; only use it when threads are not in direct competition for timestamp ties (i.e., they are executing independent statements).

See Also:

AbstractMonotonicTimestampGenerator

Constructor Summary

Constructors

Constructor and Description
ThreadLocalMonotonicTimestampGenerator() Creates a new instance with a warning threshold and warning interval of one second.
ThreadLocalMonotonicTimestampGenerator(long warningThreshold, TimeUnit warningThresholdUnit, long warningInterval, TimeUnit warningIntervalUnit) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
long	next() Returns the next timestamp.

Methods inherited from class com.datastax.driver.core.LoggingMonotonicTimestampGenerator

onDrift

Methods inherited from class com.datastax.driver.core.AbstractMonotonicTimestampGenerator

computeNext

Methods inherited from class java.lang.Object

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

Constructor Detail

ThreadLocalMonotonicTimestampGenerator

public ThreadLocalMonotonicTimestampGenerator()

Creates a new instance with a warning threshold and warning interval of one second.

See Also:

ThreadLocalMonotonicTimestampGenerator(long, TimeUnit, long, TimeUnit)

ThreadLocalMonotonicTimestampGenerator

public ThreadLocalMonotonicTimestampGenerator(long warningThreshold,
                                              TimeUnit warningThresholdUnit,
                                              long warningInterval,
                                              TimeUnit warningIntervalUnit)

Creates a new instance.

Parameters:

warningThreshold - how far in the future timestamps are allowed to drift before a warning is logged.

warningThresholdUnit - the unit for warningThreshold.

warningInterval - how often the warning will be logged if timestamps keep drifting above the threshold.

warningIntervalUnit - the unit for warningIntervalUnit.

Method Detail

next

public long next()

Description copied from interface: TimestampGenerator

Returns the next timestamp.

Implementors should enforce increasing monotonicity of timestamps, that is, a timestamp returned should always be strictly greater that any previously returned timestamp.

Implementors should strive to achieve microsecond precision in the best possible way, which is usually largely dependent on the underlying operating system's capabilities.

Returns:

the next timestamp (in microseconds). If it equals Long.MIN_VALUE, it won't be sent by the driver, letting Cassandra generate a server-side timestamp.