org.opencredo.esper
Class EsperStatement

java.lang.Object
  org.opencredo.esper.EsperStatement

All Implemented Interfaces:

EsperStatementOperations

public class EsperStatement
extends java.lang.Object
implements EsperStatementOperations

Implements a set of convenient Template operations around a native Esper Statement. Support both the push (via listener or subscriber) or pull (via the template methods) operations to retrieve results from the associated statement. For more information on push and pull operations on esper statements, see http://esper.codehaus.org/esper-3.3.0/doc/reference/en/html/api.html#api-receive-results

Author:

Russ Miles (russ.miles@opencredo.com)

Constructor Summary

EsperStatement(java.lang.String epl)

Method Summary

void	addListener(com.espertech.esper.client.UpdateListener listener) Adds an {@link UpdateListener) to the statement to support the 'push' mode of retrieving results.
<T> java.util.List<T>	concurrentSafeQuery(ParameterizedEsperRowMapper<T> rm) Performs a concurrency safe 'pull' to retrieve query filtered results from the esper statement.
<T> T	concurrentSafeQueryForObject(ParameterizedEsperRowMapper<T> rm) Performs a concurrency safe 'pull' to retrieve query filtered results from the esper statement.
<T> java.util.List<T>	concurrentUnsafeQuery(ParameterizedEsperRowMapper<T> rm) Performs a concurrency unsafe 'pull' (i.e.
<T> T	concurrentUnsafeQueryForObject(ParameterizedEsperRowMapper<T> rm) Performs a concurrency unsafe 'pull' (i.e.
void	doWithNativeEPStatement(NativeEPStatementCallback callback) Provides a mechanism by which to access the underlying esper API
java.lang.String	getEPL()
java.util.Set<com.espertech.esper.client.UpdateListener>	getListeners()
com.espertech.esper.client.EPStatementState	getState()
void	setListeners(java.util.Set<com.espertech.esper.client.UpdateListener> listeners)
void	setSubscriber(java.lang.Object subscriber)
void	start() Starts events being collated according to the statement's filter query
void	stop() Stops the underlying native statement from applying its filter query.

Methods inherited from class java.lang.Object

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

Constructor Detail

EsperStatement

public EsperStatement(java.lang.String epl)

Method Detail

getEPL

public java.lang.String getEPL()

getState

public com.espertech.esper.client.EPStatementState getState()

start

public void start()

Starts events being collated according to the statement's filter query

stop

public void stop()

Stops the underlying native statement from applying its filter query.

doWithNativeEPStatement

public void doWithNativeEPStatement(NativeEPStatementCallback callback)

Provides a mechanism by which to access the underlying esper API

Parameters:

callback - used to pass access to the underlying esper API resources

setListeners

public void setListeners(java.util.Set<com.espertech.esper.client.UpdateListener> listeners)

getListeners

public java.util.Set<com.espertech.esper.client.UpdateListener> getListeners()

setSubscriber

public void setSubscriber(java.lang.Object subscriber)

addListener

public void addListener(com.espertech.esper.client.UpdateListener listener)

Adds an {@link UpdateListener) to the statement to support the 'push' mode of retrieving results.

Parameters:

listener - The listener to be invoked when appropriate results according to the EPL filter query.

concurrentSafeQuery

public <T> java.util.List<T> concurrentSafeQuery(ParameterizedEsperRowMapper<T> rm)

Description copied from interface: EsperStatementOperations

Performs a concurrency safe 'pull' to retrieve query filtered results from the esper statement. The supplied ParameterizedEsperRowMapper is then used to populate the objects that are then collected together and returned as a List.

Specified by:

concurrentSafeQuery in interface EsperStatementOperations

Parameters:

rm - the ParameterizedEsperRowMapper to use for result mapping

Returns:

a list containing all the objects mapped from the query results

concurrentSafeQueryForObject

public <T> T concurrentSafeQueryForObject(ParameterizedEsperRowMapper<T> rm)

Description copied from interface: EsperStatementOperations

Performs a concurrency safe 'pull' to retrieve query filtered results from the esper statement. Be aware that this operation will lock the underlying esper statement resources while executing.

Specified by:

concurrentSafeQueryForObject in interface EsperStatementOperations

Parameters:

rm - the ParameterizedEsperRowMapper to use for result mapping

Returns:

the single mapped object

concurrentUnsafeQuery

public <T> java.util.List<T> concurrentUnsafeQuery(ParameterizedEsperRowMapper<T> rm)

Description copied from interface: EsperStatementOperations

Performs a concurrency unsafe 'pull' (i.e. should only be used in a single threaded environment) to retrieve query filtered results from the esper statement. The supplied ParameterizedEsperRowMapper is then used to populate the objects that are then collected together and returned as a List.

Specified by:

concurrentUnsafeQuery in interface EsperStatementOperations

Parameters:

rm - the ParameterizedEsperRowMapper to use for result mapping

Returns:

a list containing all the objects mapped from the query results

concurrentUnsafeQueryForObject

public <T> T concurrentUnsafeQueryForObject(ParameterizedEsperRowMapper<T> rm)

Description copied from interface: EsperStatementOperations

Performs a concurrency unsafe 'pull' (i.e. should only be used in a single threaded environment) to retrieve a query filtered result from the esper statement. The supplied ParameterizedEsperRowMapper is then used to populate the object that is returned.

Specified by:

concurrentUnsafeQueryForObject in interface EsperStatementOperations

Parameters:

rm - the ParameterizedEsperRowMapper to use for result mapping

Returns:

the mapped object