org.apache.metamodel.dynamodb

Class DynamoDbDataContext

java.lang.Object

org.apache.metamodel.AbstractDataContext

org.apache.metamodel.QueryPostprocessDataContext

org.apache.metamodel.dynamodb.DynamoDbDataContext

All Implemented Interfaces:

Closeable, AutoCloseable, HasReadTypeConverters, DataContext, UpdateableDataContext

public class DynamoDbDataContext
extends QueryPostprocessDataContext
implements UpdateableDataContext, Closeable

DataContext implementation for Amazon DynamoDB.

Field Summary

Fields

Modifier and Type	Field and Description
static String	SCHEMA_NAME The artificial schema name used by this DataContext.
static String	SYSTEM_PROPERTY_THROUGHPUT_READ_CAPACITY System property key used for getting the read throughput capacity when creating new tables.
static String	SYSTEM_PROPERTY_THROUGHPUT_WRITE_CAPACITY System property key used for getting the write throughput capacity when creating new tables.

Fields inherited from class org.apache.metamodel.QueryPostprocessDataContext

INFORMATION_SCHEMA_NAME, SYSTEM_PROPERTY_CREATE_DEFAULT_TABLE_ALIAS

Constructor Summary

Constructors

Constructor and Description
DynamoDbDataContext()
DynamoDbDataContext(com.amazonaws.services.dynamodbv2.AmazonDynamoDB client)
DynamoDbDataContext(com.amazonaws.services.dynamodbv2.AmazonDynamoDB client, SimpleTableDef[] tableDefs)
DynamoDbDataContext(SimpleTableDef[] tableDefs)

Method Summary

Modifier and Type	Method and Description
void	close()
protected Number	executeCountQuery(Table table, List<FilterItem> whereItems, boolean functionApproximationAllowed) Executes a simple count query, if possible.
protected Row	executePrimaryKeyLookupQuery(Table table, List<SelectItem> selectItems, Column primaryKeyColumn, Object keyValue) Executes a query which obtains a row by primary key (as defined by Column.isPrimaryKey()).
UpdateSummary	executeUpdate(UpdateScript update) Submits an UpdateScript for execution on the DataContext.
com.amazonaws.services.dynamodbv2.AmazonDynamoDB	getDynamoDb()
protected Schema	getMainSchema()
protected String	getMainSchemaName()
protected DataSet	materializeMainSchemaTable(Table table, List<Column> columns, int maxRows) Executes a simple one-table query against a table in the main schema of the subclasses of this class.

Methods inherited from class org.apache.metamodel.QueryPostprocessDataContext

addConverter, executeQuery, getDefaultSchemaName, getSchemaByNameInternal, getSchemaNamesInternal, isMainSchemaTable, isScalarFunctionMaterialized, materializeFromItem, materializeMainSchemaTable, materializeMainSchemaTable, materializeMainSchemaTableSelect, materializeTable

Methods inherited from class org.apache.metamodel.AbstractDataContext

compileQuery, executeQuery, executeQuery, getColumnByQualifiedLabel, getDefaultSchema, getSchemaByName, getSchemaNames, getSchemas, getTableByQualifiedLabel, isQualifiedPathDelim, onSchemaCacheRefreshed, parseQuery, query, refreshSchemas

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.metamodel.DataContext

compileQuery, executeQuery, executeQuery, executeQuery, getColumnByQualifiedLabel, getDefaultSchema, getSchemaByName, getSchemaNames, getSchemas, getTableByQualifiedLabel, parseQuery, query, refreshSchemas

Field Detail

SYSTEM_PROPERTY_THROUGHPUT_READ_CAPACITY

public static final String SYSTEM_PROPERTY_THROUGHPUT_READ_CAPACITY

System property key used for getting the read throughput capacity when creating new tables. Defaults to 5.

See Also:

Constant Field Values

SYSTEM_PROPERTY_THROUGHPUT_WRITE_CAPACITY

public static final String SYSTEM_PROPERTY_THROUGHPUT_WRITE_CAPACITY

System property key used for getting the write throughput capacity when creating new tables. Defaults to 5.

See Also:

Constant Field Values

SCHEMA_NAME

public static final String SCHEMA_NAME

The artificial schema name used by this DataContext.

See Also:

Constant Field Values

Constructor Detail

DynamoDbDataContext

public DynamoDbDataContext()

DynamoDbDataContext

public DynamoDbDataContext(SimpleTableDef[] tableDefs)

DynamoDbDataContext

public DynamoDbDataContext(com.amazonaws.services.dynamodbv2.AmazonDynamoDB client)

DynamoDbDataContext

public DynamoDbDataContext(com.amazonaws.services.dynamodbv2.AmazonDynamoDB client,
                           SimpleTableDef[] tableDefs)

Method Detail

getDynamoDb

public com.amazonaws.services.dynamodbv2.AmazonDynamoDB getDynamoDb()

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

getMainSchema

protected Schema getMainSchema()
                        throws MetaModelException

Specified by:

getMainSchema in class QueryPostprocessDataContext

Returns:

the main schema that subclasses of this class produce

Throws:

MetaModelException

getMainSchemaName

protected String getMainSchemaName()
                            throws MetaModelException

Specified by:

getMainSchemaName in class QueryPostprocessDataContext

Returns:

the name of the main schema that subclasses of this class produce

Throws:

MetaModelException

executeCountQuery

protected Number executeCountQuery(Table table,
                                   List<FilterItem> whereItems,
                                   boolean functionApproximationAllowed)

Description copied from class: QueryPostprocessDataContext

Executes a simple count query, if possible. This method is provided to allow subclasses to optimize count queries since they are quite common and often a datastore can retrieve the count using some specialized means which is much more performant than counting all records manually.

Overrides:

executeCountQuery in class QueryPostprocessDataContext

Parameters:

table - the table on which the count is requested.

whereItems - a (sometimes empty) list of WHERE items.

functionApproximationAllowed - whether approximation is allowed or not.

Returns:

the count of the particular table, or null if not available.

materializeMainSchemaTable

protected DataSet materializeMainSchemaTable(Table table,
                                             List<Column> columns,
                                             int maxRows)

Description copied from class: QueryPostprocessDataContext

Executes a simple one-table query against a table in the main schema of the subclasses of this class.

Specified by:

materializeMainSchemaTable in class QueryPostprocessDataContext

Parameters:

table - the table to query

columns - the columns of the table to query

maxRows - the maximum amount of rows needed or -1 if all rows are wanted.

Returns:

a dataset with the raw table/column content.

executePrimaryKeyLookupQuery

protected Row executePrimaryKeyLookupQuery(Table table,
                                           List<SelectItem> selectItems,
                                           Column primaryKeyColumn,
                                           Object keyValue)

Description copied from class: QueryPostprocessDataContext

Executes a query which obtains a row by primary key (as defined by Column.isPrimaryKey()). This method is provided to allow subclasses to optimize lookup queries since they are quite common and often a datastore can retrieve the row using some specialized means which is much more performant than scanning all records manually.

Overrides:

executePrimaryKeyLookupQuery in class QueryPostprocessDataContext

Parameters:

table - the table on which the lookup is requested.

selectItems - the items to select from the lookup query.

primaryKeyColumn - the column that is the primary key

keyValue - the primary key value that is specified in the lookup query.

Returns:

the row if the particular table, or null if not available.

executeUpdate

public UpdateSummary executeUpdate(UpdateScript update)

Description copied from interface: UpdateableDataContext

Submits an UpdateScript for execution on the DataContext. Since implementations of the DataContext vary quite a lot, there is no golden rule as to how an update script will be executed. But the implementors should strive towards handling an UpdateScript as a single transactional change to the data store.

Specified by:

executeUpdate in interface UpdateableDataContext

Parameters:

update - the update script to execute

Returns:

a summary of the updates performed