Class StatelessJdbcListener

java.lang.Object

org.frankframework.jdbc.JdbcFacade

org.frankframework.jdbc.AbstractJdbcListener

org.frankframework.jdbc.StatelessJdbcListener

All Implemented Interfaces:

FrankElement, HasApplicationContext, HasName, HasPhysicalDestination, IConfigurable, IListener<Serializable>, IPeekableListener<Serializable>, IPullingListener<Serializable>, IScopeProvider, NameAware, TransactionAware, ConfigurableLifecycle, org.springframework.beans.factory.Aware, org.springframework.context.ApplicationContextAware, org.springframework.context.Lifecycle, org.springframework.context.Phased, org.springframework.context.SmartLifecycle

@Category(EXPERIMENTAL)
public class StatelessJdbcListener
extends AbstractJdbcListener
implements IPeekableListener<Serializable>, IPullingListener<Serializable>

A JDBC Listener that does not maintain any processing-state in the table to which it listens. The listener will pick up the message-field, key field, message-id field, correlation-id and additional fields from the first record returned by the select-query.

This listener does not maintain any processing-state in the table, like the JdbcTableListener or MessageStoreListener do. To prevent messages from being picked up by multiple instances of the same listener, queries will always use SELECT .... FOR UPDATE to make sure the rows are locked.

In transactional Receivers this will keep the row locked for the entire duration of the pipeline, potentially stalling other processes. Because there is no state-change management, everything will happen in a single transaction.

To prevent the same message being picked up again after the pipeline completes, you should either remove it, or update it so that it no longer matches the SELECT conditions of the query. You can either:

• Use a FixedQuerySender in your pipeline to delete the row
• Use a setAfterProcessQuery(String) which is automatically executed when the pipeline finishes
• Use a setAfterSelectQuery(String) which can delete the row immediately after it has been selected and read

NB: If the pipeline fails and was executed transactionally, the transaction will be rolled back and so any SQL statements that have deleted or updated the row will also be rolled back.

The setSelectQuery(String) and AbstractJdbcListener.setPeekQuery(String) will be automatically modified to be SELECT ... FOR UPDATE or SELECT ... FOR SHARE SKIP LOCKED queries. With some databases this means you cannot grouping queries or queries using COUNT(...), SUM(...) or similar statements.

This listener does not do any validation of the queries in configuration, or when opened. Any errors in your queries can result in a heavy load on the system as queries are retried in quick succession, so be careful with the configuration.
All the fields which you want to use and have configured as either key, message, message-id, correlation-id or additionalFields need to be added to the SELECT clause of your query with the exact same name.
If a field is missing or incorrectly spelled, it will either be silently dropped or may default to another value.

Field Summary

Fields inherited from class AbstractJdbcListener

ADDITIONAL_QUERY_FIELDS_KEY, additionalFields, additionalFieldsList, correlationIdField, keyField, messageField, messageIdField, peekQuery, peekUntransacted, preparedPeekQuery, preparedSelectQuery, selectQuery, trace

Fields inherited from class JdbcFacade

log

Fields inherited from interface org.springframework.context.SmartLifecycle

DEFAULT_PHASE

Constructor Summary

Constructors

Constructor	Description
StatelessJdbcListener()

Method Summary

Modifier and Type	Method	Description
void	afterMessageProcessed(PipeLineResult processResult, RawMessageWrapper<Serializable> rawMessage, PipeLineSession pipeLineSession)	Called to perform actions (like committing or sending a reply) after a message has been processed by the Pipeline.
void	configure()	Configure this component.
@Nullable RawMessageWrapper<Serializable>	getRawMessage(@NonNull Map<String,Object> threadContext)	Retrieves messages from queue or other channel, but does no processing on it.
boolean	hasRawMessageAvailable()
void	setAfterProcessQuery(String afterProcessQuery)	A SQL statement (UPDATE or DELETE) that can optionally be used to make sure the SELECT query does not pick up the same row again.
void	setAfterSelectQuery(String afterSelectQuery)	A SQL statement (UPDATE or DELETE) that can optionally be used to make sure the SELECT query does not pick up the same row again.
void	setSelectQuery(String string)

Methods inherited from class AbstractJdbcListener

addAdditionalValuesToMessageWrapper, closeThread, execute, extractMessage, extractRawMessage, getColumnValueOrDefault, getMessageKeyOrNull, openThread, setAdditionalFields, setCorrelationIdField, setKeyField, setMessageField, setMessageIdField, setPeekQuery, setPeekUntransacted

Methods inherited from class JdbcFacade

convertQuery, getConnection, getConnectionWithTimeout, getDatasource, getDatasourceName, getDbmsSupport, getLogPrefix, getPassword, getPhysicalDestinationName, isRunning, setAuthAlias, setBlobCharset, setBlobsCompressed, setBlobSmartGet, setDatasourceName, setDbmsSupportFactory, setName, setPassword, setSqlDialect, setUsername, start, stop, withConnection, withConnection

Methods inherited from class Object

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

Methods inherited from interface org.springframework.context.ApplicationContextAware

setApplicationContext

Methods inherited from interface ConfigurableLifecycle

getPhase, isAutoStartup, isConfigured

Methods inherited from interface FrankElement

addConfigWarning

Methods inherited from interface HasApplicationContext

getApplicationContext, getConfigurationClassLoader

Methods inherited from interface HasName

getName

Methods inherited from interface IListener

extractMessage, start, stop

Methods inherited from interface IPeekableListener

isPeekUntransacted, setPeekUntransacted

Methods inherited from interface IPullingListener

closeThread, openThread

Methods inherited from interface NameAware

setName

Methods inherited from interface org.springframework.context.SmartLifecycle

isPauseable, stop

Constructor Details

StatelessJdbcListener

public StatelessJdbcListener()

Method Details

configure

public void configure()
               throws ConfigurationException

Description copied from interface: IConfigurable

Configure this component.

configure() is called once at startup of the framework in the configure method of the owner of this IConfigurable. Purpose of this method is to check whether the static configuration of the object is correct. As much as possible class-instantiating should take place in the configure(), to improve performance.

In the case of a container, this will propagate the configure signal to all components that apply.

Specified by:

configure in interface IConfigurable

Overrides:

configure in class AbstractJdbcListener

Throws:

ConfigurationException - in case it was not able to configure the component.

hasRawMessageAvailable

public boolean hasRawMessageAvailable()
                               throws ListenerException

Specified by:

hasRawMessageAvailable in interface IPeekableListener<Serializable>

Overrides:

hasRawMessageAvailable in class AbstractJdbcListener

Throws:

ListenerException

getRawMessage

public @Nullable RawMessageWrapper<Serializable> getRawMessage(@NonNull Map<String,Object> threadContext)
                                                        throws ListenerException

Description copied from interface: IPullingListener

Retrieves messages from queue or other channel, but does no processing on it. Multiple objects may try to call this method at the same time, from different threads. Implementations of this method should therefore be thread-safe, or synchronized.

Any thread-specific properties should be stored in and retrieved from the threadContext.

If the returned object is an instance of MessageWrapper then the

invalid reference

org.frankframework.receivers.Receiver#processRawMessage(IListener, RawMessageWrapper, PipeLineSession, boolean)

will not call IListener.extractMessage(RawMessageWrapper, Map) but directly access the enclosed Message and the

invalid reference

RawMessageWrapper#getContext()

.

Specified by:

getRawMessage in interface IPullingListener<Serializable>

Throws:

ListenerException

afterMessageProcessed

public void afterMessageProcessed(PipeLineResult processResult,
 RawMessageWrapper<Serializable> rawMessage,
 PipeLineSession pipeLineSession)
                           throws ListenerException

Description copied from interface: IListener

Called to perform actions (like committing or sending a reply) after a message has been processed by the Pipeline.

Specified by:

afterMessageProcessed in interface IListener<Serializable>

Throws:

ListenerException

setAfterSelectQuery

public void setAfterSelectQuery(String afterSelectQuery)

A SQL statement (UPDATE or DELETE) that can optionally be used to make sure the SELECT query does not pick up the same row again. The afterSelectQuery is executed immediately after the SELECT query, before the pipeline is executed.
The query can have up to 3 parameters, values of which are taken in order from the fields mapped to AbstractJdbcListener.setKeyField(String), AbstractJdbcListener.setMessageIdField(String) and AbstractJdbcListener.setCorrelationIdField(String) in the setSelectQuery(String).

Deleting or updating the selected row immediately might reduce lock-contention on the table, however the row is not available anymore in the pipeline for other queries.

If the Receiver is transactional, and the pipeline fails, the transaction is rolled back so the afterSelectQuery is rolled back.

setAfterProcessQuery

public void setAfterProcessQuery(String afterProcessQuery)

A SQL statement (UPDATE or DELETE) that can optionally be used to make sure the SELECT query does not pick up the same row again. The afterProcessQuery is executed after the pipeline has finished.
The query can have up to 3 parameters, values of which are taken in order from the fields mapped to AbstractJdbcListener.setKeyField(String), AbstractJdbcListener.setMessageIdField(String) and AbstractJdbcListener.setCorrelationIdField(String) in the setSelectQuery(String).

Deleting or updating the selected row after processing in the pipeline is complete means the data of the row can be queried again in the pipeline, but also keeps the row locked for other queries outside the transaction.

The afterProcessQuery is executed only when the pipeline has finished successfully.

If the Receiver is transactional, and the transaction is rolled back, the afterProcessQuery is rolled back if it was executed.

setSelectQuery

public void setSelectQuery(String string)

Overrides:

setSelectQuery in class AbstractJdbcListener