org.axonframework.modelling.saga.repository.jdbc

Class PostgresSagaSqlSchema

java.lang.Object

org.axonframework.modelling.saga.repository.jdbc.GenericSagaSqlSchema

org.axonframework.modelling.saga.repository.jdbc.PostgresSagaSqlSchema

All Implemented Interfaces:

SagaSqlSchema

public class PostgresSagaSqlSchema
extends GenericSagaSqlSchema

SQL schema supporting PostgreSQL databases.

This implementation uses the appropriate PostgreSQL data types (serial, bytea).

Since:

2.4

Author:

Jochen Munz

Field Summary

Fields inherited from class org.axonframework.modelling.saga.repository.jdbc.GenericSagaSqlSchema

sagaSchema

Constructor Summary

Constructors

Constructor and Description
PostgresSagaSqlSchema() Initialize a PostgresSagaSqlSchema using the default schema configuration.
PostgresSagaSqlSchema(SagaSchema sagaSchema) Initialize a PostgresSagaSqlSchema using the given sagaSchema.

Method Summary

Modifier and Type	Method and Description
void	setExclusiveLoad(boolean exclusiveLoad) Sets whether loading of Sagas should occur exclusively by a single node, by requiring a row lock from the database.
PreparedStatement	sql_createTableAssocValueEntry(Connection conn) Creates a PreparedStatement that creates the table for storing Association Values for Sagas.
PreparedStatement	sql_createTableSagaEntry(Connection conn) Creates a PreparedStatement that creates the table for storing Sagas.
PreparedStatement	sql_loadSaga(Connection connection, String sagaId) Creates a PreparedStatement that loads a single Saga, with given sagaId.

Methods inherited from class org.axonframework.modelling.saga.repository.jdbc.GenericSagaSqlSchema

readAssociationValues, readSerializedSaga, readToken, sagaSchema, sql_deleteAssociationEntries, sql_deleteSagaEntry, sql_findAssociations, sql_findAssocSagaIdentifiers, sql_removeAssocValue, sql_storeAssocValue, sql_storeSaga, sql_updateSaga

Methods inherited from class java.lang.Object

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

Constructor Detail

PostgresSagaSqlSchema

public PostgresSagaSqlSchema()

Initialize a PostgresSagaSqlSchema using the default schema configuration.

PostgresSagaSqlSchema

public PostgresSagaSqlSchema(SagaSchema sagaSchema)

Initialize a PostgresSagaSqlSchema using the given sagaSchema.

Parameters:

sagaSchema - the saga schema configuration

Method Detail

sql_createTableAssocValueEntry

public PreparedStatement sql_createTableAssocValueEntry(Connection conn)
                                                 throws SQLException

Description copied from interface: SagaSqlSchema

Creates a PreparedStatement that creates the table for storing Association Values for Sagas.

Specified by:

sql_createTableAssocValueEntry in interface SagaSqlSchema

Overrides:

sql_createTableAssocValueEntry in class GenericSagaSqlSchema

Parameters:

conn - The connection to create the PreparedStatement for

Returns:

a Prepared statement that created the Association Value table, when executed

Throws:

SQLException - when an error occurs creating the PreparedStatement

sql_createTableSagaEntry

public PreparedStatement sql_createTableSagaEntry(Connection conn)
                                           throws SQLException

Description copied from interface: SagaSqlSchema

Creates a PreparedStatement that creates the table for storing Sagas.

Specified by:

sql_createTableSagaEntry in interface SagaSqlSchema

Overrides:

sql_createTableSagaEntry in class GenericSagaSqlSchema

Parameters:

conn - The connection to create the PreparedStatement for

Returns:

a Prepared statement that created the Saga table, when executed

Throws:

SQLException - when an error occurs creating the PreparedStatement

sql_loadSaga

public PreparedStatement sql_loadSaga(Connection connection,
                                      String sagaId)
                               throws SQLException

Description copied from interface: SagaSqlSchema

Creates a PreparedStatement that loads a single Saga, with given sagaId.

Specified by:

sql_loadSaga in interface SagaSqlSchema

Overrides:

sql_loadSaga in class GenericSagaSqlSchema

Parameters:

connection - The connection to create the PreparedStatement for

sagaId - The identifier of the Saga to return

Returns:

a statement, that creates a result set to be processed by SagaSqlSchema.readSerializedSaga(java.sql.ResultSet), when executed

Throws:

SQLException - when an error occurs creating the PreparedStatement

setExclusiveLoad

public void setExclusiveLoad(boolean exclusiveLoad)

Sets whether loading of Sagas should occur exclusively by a single node, by requiring a row lock from the database.

If true, only one instance of the application may load a saga at a time. This may be used to serialize event handling in sagas in multi-node configurations where no StreamingEventProcessor is used. The given processor type caveat is explained through the fact that a StreamingEventProcessor requires claimed segments to be able to perform any event handling work. Furthermore, this segments originate from a shared resources in a distributed environment.

As such, a Saga cannot be accessed concurrently through the StreamingEventProcessor. And hence, setting exclusiveLoad to true would not change the underlying behavior at all.