com.google.cloud.spanner.watcher

Class TimebasedShardProvider

java.lang.Object

com.google.cloud.spanner.watcher.TimebasedShardProvider

All Implemented Interfaces:

ShardProvider

public final class TimebasedShardProvider
extends Object
implements ShardProvider

Implementation of ShardProvider that generates a ShardId based on the current system time of Cloud Spanner. The generated shard id groups a set of commit timestamps together. The TimebasedShardProvider can only be used when all clients that write to the tables that are being watched update the shard column with the most recent shard id for each update that is written to the tables.

See Also:

for an example on how to use this {@link ShardProvider}.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TimebasedShardProvider.Interval
static class	TimebasedShardProvider.TimebasedShardId A generated timebased shard id that has been fetched from Cloud Spanner.

Method Summary

Modifier and Type	Method and Description
void	appendShardFilter(com.google.cloud.spanner.Statement.Builder statement) Appends the required sharding filter to the given statement.
static TimebasedShardProvider	create(String column, TimebasedShardProvider.Interval interval) Creates a TimebasedShardProvider for the given database column and interval.
com.google.cloud.spanner.Value	getShardValue() Returns the (fixed) value that is used by this ShardProvider.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.google.cloud.spanner.watcher.ShardProvider

getColumnName

Method Detail

create

public static TimebasedShardProvider create(String column,
                                            TimebasedShardProvider.Interval interval)

Creates a TimebasedShardProvider for the given database column and interval.

appendShardFilter

public void appendShardFilter(com.google.cloud.spanner.Statement.Builder statement)

Description copied from interface: ShardProvider

Appends the required sharding filter to the given statement. This could be an SQL fragment or one or more parameters or a combination of both.

Specified by:

appendShardFilter in interface ShardProvider

getShardValue

@Nullable
public com.google.cloud.spanner.Value getShardValue()

Description copied from interface: ShardProvider

Returns the (fixed) value that is used by this ShardProvider. This value will be passed to the CommitTimestampRepository to indicate the last seen commit timestamp for a certain shard. This value will be null if the ShardProvider does not use a fixed value.

Specified by:

getShardValue in interface ShardProvider