com.google.cloud.spanner.watcher

Class FixedShardProvider

java.lang.Object

com.google.cloud.spanner.watcher.FixedShardProvider

All Implemented Interfaces:

ShardProvider

public class FixedShardProvider
extends Object
implements ShardProvider

Implementation of ShardProvider that returns a fixed shard id. This can be used in combination with multiple change watchers, where each change watcher is responsible for watching a specific segment of the table.

It can also be used to watch all segments of a table by setting the shard id to an array of all possible values in the shard column.

Example usage in combination with a SpannerTableTailer:

 String shards = new String[] {"EAST", "WEST"};
 for (String shard : shards) {
   SpannerTableTailer tailer =
       SpannerTableTailer.newBuilder(
               spanner, TableId.of(databaseId, "TABLE_NAME"))
           .setShardProvider(FixedShardProvider.create("SHARD_COLUMN", shard))
           .build();
 }
 

Method Summary

Modifier and Type	Method and Description
void	appendShardFilter(com.google.cloud.spanner.Statement.Builder statementBuilder) Appends the required sharding filter to the given statement.
static FixedShardProvider	create(String column, BigDecimal value)
static FixedShardProvider	create(String column, boolean value)
static FixedShardProvider	create(String column, com.google.cloud.ByteArray value)
static FixedShardProvider	create(String column, com.google.cloud.Date value)
static FixedShardProvider	create(String column, double value)
static FixedShardProvider	create(String column, long value)
static FixedShardProvider	create(String column, String value)
static FixedShardProvider	create(String column, com.google.cloud.Timestamp value)
static FixedShardProvider	create(String column, com.google.cloud.spanner.Value value)
String	getColumnName() Returns the name of the column that this shard provider uses.
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

Method Detail

create

public static FixedShardProvider create(String column,
                                        boolean value)

create

public static FixedShardProvider create(String column,
                                        com.google.cloud.ByteArray value)

create

public static FixedShardProvider create(String column,
                                        com.google.cloud.Date value)

create

public static FixedShardProvider create(String column,
                                        double value)

create

public static FixedShardProvider create(String column,
                                        long value)

create

public static FixedShardProvider create(String column,
                                        BigDecimal value)

create

public static FixedShardProvider create(String column,
                                        String value)

create

public static FixedShardProvider create(String column,
                                        com.google.cloud.Timestamp value)

create

public static FixedShardProvider create(String column,
                                        com.google.cloud.spanner.Value value)

appendShardFilter

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

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

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

getColumnName

public String getColumnName()

Description copied from interface: ShardProvider

Returns the name of the column that this shard provider uses.

Specified by:

getColumnName in interface ShardProvider