com.gpudb

Class RecordRetriever<T>

java.lang.Object

com.gpudb.RecordRetriever<T>

Type Parameters:

T - the type of object being retrieved

public class RecordRetriever<T>
extends Object

Object that permits efficient retrieval of records from GPUdb, with support for multi-head access. RecordRetriever instances are thread safe and may be used from any number of threads simultaneously.

Constructor Summary

Constructors

Constructor and Description
RecordRetriever(GPUdb gpudb, String tableName, Type type) Creates a RecordRetriever with the specified parameters.
RecordRetriever(GPUdb gpudb, String tableName, TypeObjectMap<T> typeObjectMap) Creates a RecordRetriever with the specified parameters.
RecordRetriever(GPUdb gpudb, String tableName, TypeObjectMap<T> typeObjectMap, WorkerList workers) Creates a RecordRetriever with the specified parameters.
RecordRetriever(GPUdb gpudb, String tableName, Type type, WorkerList workers) Creates a RecordRetriever with the specified parameters.

Method Summary

Modifier and Type	Method and Description
GetRecordsResponse<T>	getByKey(List<Object> keyValues, String expression) Retrieves records for a given shard key, optionally further limited by an additional expression.
GPUdb	getGPUdb() Gets the GPUdb instance from which records will be retrieved.
String	getTableName() Gets the name of the table from which records will be retrieved.

Methods inherited from class java.lang.Object

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

Constructor Detail

RecordRetriever

public RecordRetriever(GPUdb gpudb,
                       String tableName,
                       Type type)
                throws GPUdbException

Creates a RecordRetriever with the specified parameters.

Parameters:

gpudb - the GPUdb instance to retrieve records from

tableName - the table to retrieve records from

type - the type of records being retrieved

Throws:

GPUdbException - if a configuration error occurs

IllegalArgumentException - if an invalid parameter is specified

RecordRetriever

public RecordRetriever(GPUdb gpudb,
                       String tableName,
                       Type type,
                       WorkerList workers)
                throws GPUdbException

Creates a RecordRetriever with the specified parameters.

Parameters:

gpudb - the GPUdb instance to retrieve records from

tableName - the table to retrieve records from

type - the type of records being retrieved

workers - worker list for multi-head retrieval (null to disable multi-head retrieval)

Throws:

GPUdbException - if a configuration error occurs

IllegalArgumentException - if an invalid parameter is specified

RecordRetriever

public RecordRetriever(GPUdb gpudb,
                       String tableName,
                       TypeObjectMap<T> typeObjectMap)
                throws GPUdbException

Creates a RecordRetriever with the specified parameters.

Parameters:

gpudb - the GPUdb instance to retrieve records from

tableName - the table to retrieve records from

typeObjectMap - type object map for the type of records being retrieved

Throws:

GPUdbException - if a configuration error occurs

IllegalArgumentException - if an invalid parameter is specified

RecordRetriever

public RecordRetriever(GPUdb gpudb,
                       String tableName,
                       TypeObjectMap<T> typeObjectMap,
                       WorkerList workers)
                throws GPUdbException

Creates a RecordRetriever with the specified parameters.

Parameters:

gpudb - the GPUdb instance to retrieve records from

tableName - the table to retrieve records from

typeObjectMap - type object map for the type of records being retrieved

workers - worker list for multi-head retrieval (null to disable multi-head retrieval)

Throws:

GPUdbException - if a configuration error occurs

IllegalArgumentException - if an invalid parameter is specified

Method Detail

getGPUdb

public GPUdb getGPUdb()

Gets the GPUdb instance from which records will be retrieved.

Returns:

the GPUdb instance from which records will be retrieved

getTableName

public String getTableName()

Gets the name of the table from which records will be retrieved.

Returns:

the name of the table from which records will be retrieved

getByKey

public GetRecordsResponse<T> getByKey(List<Object> keyValues,
                                      String expression)
                               throws GPUdbException

Retrieves records for a given shard key, optionally further limited by an additional expression. All records matching the key and satisfying the expression will be returned, up to the system-defined limit. For multi-head mode the request will be sent directly to the appropriate worker.

All fields in both the shard key and the expression must have defined attribute indexes, unless the shard key is also a primary key and all referenced fields are in the primary key. The expression must be limited to basic equality and inequality comparisons that can be evaluated using the attribute indexes.

Parameters:

keyValues - list of values that make up the shard key; the values must be in the same order as in the table and have the correct data types

expression - additional filter to be applied, or null for none

Returns:

response object containing the results

Throws:

GPUdbException - if an error occurs during the operation