org.apache.samza.table.descriptors

Interface TableDescriptor<K,V,D extends TableDescriptor<K,V,D>>

Type Parameters:

K - the type of the key in this table

V - the type of the value in this table

D - the type of the concrete table descriptor

All Known Implementing Classes:

BaseTableDescriptor, CachingTableDescriptor, GuavaCacheTableDescriptor, HybridTableDescriptor, LocalTableDescriptor, RemoteTableDescriptor

@InterfaceStability.Unstable
public interface TableDescriptor<K,V,D extends TableDescriptor<K,V,D>>

A TableDescriptor can be used for specifying Samza and implementation-specific properties of a Table.

Table properties provided in configuration override corresponding properties specified using a descriptor.

This is the base descriptor for a table. Use a implementation-specific descriptor (e.g. RocksDBTableDescriptor) to use it in the application. For example:

 RocksDbTableDescriptor tableDescriptor = new RocksDbTableDescriptor("table",
         KVSerde.of(new IntegerSerde(), new StringSerde("UTF-8")))
     .withBlockSize(1024)
     .withConfig("some-key", "some-value");
 
 

For High Level API StreamApplications, use StreamApplicationDescriptor.getTable(TableDescriptor) to obtain the corresponding Table instance that can be used with the MessageStream operators like MessageStream.sendTo(Table). Alternatively, use TaskContext.getTable(String) or TaskContext.getUpdatableTable(String) in InitableFunction.init(org.apache.samza.context.Context) to get the table instance for use within operator functions. For Low Level API TaskApplications, use TaskContext.getTable(String) in InitableTask.init(org.apache.samza.context.Context) to get the table instance for use within the Task.

Method Summary

Modifier and Type	Method and Description
java.lang.String	getTableId() Get the id of the table
java.util.Map<java.lang.String,java.lang.String>	toConfig(Config jobConfig) Generate configuration for this table descriptor, the generated configuration should be the complete configuration for this table that can be directly included in the job configuration.

Method Detail

getTableId

java.lang.String getTableId()

Get the id of the table

Returns:

id of the table

toConfig

java.util.Map<java.lang.String,java.lang.String> toConfig(Config jobConfig)

Generate configuration for this table descriptor, the generated configuration should be the complete configuration for this table that can be directly included in the job configuration. Note: although the serdes may have already been set in this instance, their corresponding configuration needs to be generated centrally for consistency and efficiency reasons. Therefore the serde configuration for this table is expected to have already been generated and stored in the jobConfig.

Parameters:

jobConfig - job configuration

Returns:

table configuration