com.espertech.esper.core.service
Class EPStatementImpl

java.lang.Object
  com.espertech.esper.core.service.EPStatementImpl

All Implemented Interfaces:

EPIterable, EPListenable, EPStatement, EPStatementSPI

public class EPStatementImpl
extends java.lang.Object
implements EPStatementSPI

Statement implementation for EPL statements.

Constructor Summary

EPStatementImpl(java.lang.String expressionNoAnnotations, boolean isPattern, DispatchService dispatchService, StatementLifecycleSvc statementLifecycleSvc, long timeLastStateChange, boolean isBlockingDispatch, boolean isSpinBlockingDispatch, long msecBlockingTimeout, TimeSourceService timeSourceService, StatementMetadata statementMetadata, java.lang.Object userObject, StatementContext statementContext, boolean isFailed, boolean nameProvided)
Ctor.

Method Summary

void	addListener(StatementAwareUpdateListener listener) Add a statement-aware listener that observes events.
void	addListener(UpdateListener listener) Add a listener to the statement.
void	addListenerWithReplay(UpdateListener listener) Add an update listener replaying current statement results to the listener.
void	destroy() Destroy the statement releasing all statement resources.
java.lang.annotation.Annotation[]	getAnnotations() Returns EPL or pattern statement annotations provided in the statement text, if any.
EventType	getEventType() Returns the type of events the iterable returns.
java.lang.String	getExpressionNoAnnotations() Returns the statements expression without annotations.
EPStatementListenerSet	getListenerSet() Returns the set of listeners to the statement.
java.lang.String	getName() Returns the statement name.
java.lang.String	getServiceIsolated() Returns the name of the isolated service provided is the statement is currently isolated in terms of event visibility and scheduling, or returns null if the statement is live in the engine.
EPStatementState	getState() Returns the statement's current state.
java.util.Iterator<StatementAwareUpdateListener>	getStatementAwareListeners() Returns an iterator of statement-aware update listeners.
StatementContext	getStatementContext() Returns the statement context.
java.lang.String	getStatementId() Returns the statement id.
StatementMetadata	getStatementMetadata() Returns additional metadata about a statement.
java.lang.Object	getSubscriber() Returns the current subscriber instance that receives statement results.
java.lang.String	getText() Returns the underlying expression text.
long	getTimeLastStateChange() Returns the system time in milliseconds of when the statement last change state.
java.util.Iterator<UpdateListener>	getUpdateListeners() Returns an iterator of update listeners.
java.lang.Object	getUserObject() Returns the application defined user data object associated with the statement, or null if none was supplied at time of statement creation.
boolean	isDestroyed() Returns true if the statement state is destroyed.
boolean	isNameProvided() True if an explicit statement name has been provided, false if the statement name is system-generated.
boolean	isPattern() Returns true if statement is a pattern
boolean	isStarted() Returns true if the statement state is started.
boolean	isStopped() Returns true if the statement state is stopped.
java.util.Iterator<EventBean>	iterator() Returns a concurrency-unsafe iterator over events representing statement results (pull API).
java.util.Iterator<EventBean>	iterator(ContextPartitionSelector selector) For use with statements that have a context declared and that may therefore have multiple context partitions, allows to iterate over context partitions selectively.
void	removeAllListeners() Remove all listeners to a statement.
void	removeListener(StatementAwareUpdateListener listener) Remove a statement-aware listener that observes events.
void	removeListener(UpdateListener listener) Remove a listeners to a statement.
SafeIterator<EventBean>	safeIterator() Returns a concurrency-safe iterator that iterates over events representing statement results (pull API) in the face of concurrent event processing by further threads.
SafeIterator<EventBean>	safeIterator(ContextPartitionSelector selector) For use with statements that have a context declared and that may therefore have multiple context partitions, allows to safe-iterate over context partitions selectively.
void	setCurrentState(EPStatementState currentState, long timeLastStateChange) Set statement state.
void	setListeners(EPStatementListenerSet listenerSet, boolean isRecovery) Sets the statement listeners.
void	setParentView(Viewable viewable) Sets the parent view.
void	setServiceIsolated(java.lang.String serviceIsolated) Set the statement's isolated service name, or null to clear.
void	setSubscriber(java.lang.Object subscriber) Attaches a subscriber to receive statement results, or removes a previously set subscriber (by providing a null value).
void	setSubscriber(java.lang.Object subscriber, java.lang.String methodName) Attaches a subscriber to receive statement results by calling the method with the provided method name, or removes a previously set subscriber (by providing a null value).
void	start() Start the statement.
void	stop() Stop the statement.

Methods inherited from class java.lang.Object

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

Constructor Detail

EPStatementImpl

public EPStatementImpl(java.lang.String expressionNoAnnotations,
                       boolean isPattern,
                       DispatchService dispatchService,
                       StatementLifecycleSvc statementLifecycleSvc,
                       long timeLastStateChange,
                       boolean isBlockingDispatch,
                       boolean isSpinBlockingDispatch,
                       long msecBlockingTimeout,
                       TimeSourceService timeSourceService,
                       StatementMetadata statementMetadata,
                       java.lang.Object userObject,
                       StatementContext statementContext,
                       boolean isFailed,
                       boolean nameProvided)

Ctor.

Parameters:

isPattern - is true to indicate this is a pure pattern expression

dispatchService - for dispatching events to listeners to the statement

statementLifecycleSvc - handles lifecycle transitions for the statement

isBlockingDispatch - is true if the dispatch to listeners should block to preserve event generation order

isSpinBlockingDispatch - true to use spin locks blocking to deliver results, as locks are usually uncontended

msecBlockingTimeout - is the max number of milliseconds of block time

timeLastStateChange - the timestamp the statement was created and started

timeSourceService - time source provider

statementMetadata - statement metadata

userObject - the application define user object associated to each statement, if supplied

statementContext - the statement service context

expressionNoAnnotations - expression text witout annotations

isFailed - indicator to start in failed state

nameProvided - true to indicate a statement name has been provided and is not a system-generated name

Method Detail

getStatementId

public java.lang.String getStatementId()

Description copied from interface: EPStatementSPI

Returns the statement id.

Specified by:

getStatementId in interface EPStatementSPI

Returns:

statement id

start

public void start()

Description copied from interface: EPStatement

Start the statement.

Specified by:

start in interface EPStatement

stop

public void stop()

Description copied from interface: EPStatement

Stop the statement.

Specified by:

stop in interface EPStatement

destroy

public void destroy()

Description copied from interface: EPStatement

Destroy the statement releasing all statement resources.

A destroyed statement cannot be started again.

Specified by:

destroy in interface EPStatement

getState

public EPStatementState getState()

Description copied from interface: EPStatement

Returns the statement's current state.

Specified by:

getState in interface EPStatement

Returns:

state enum

setCurrentState

public void setCurrentState(EPStatementState currentState,
                            long timeLastStateChange)

Description copied from interface: EPStatementSPI

Set statement state.

Specified by:

setCurrentState in interface EPStatementSPI

Parameters:

currentState - new current state

timeLastStateChange - the timestamp the statement changed state

setParentView

public void setParentView(Viewable viewable)

Description copied from interface: EPStatementSPI

Sets the parent view.

Specified by:

setParentView in interface EPStatementSPI

Parameters:

viewable - is the statement viewable

getText

public java.lang.String getText()

Description copied from interface: EPStatement

Returns the underlying expression text.

Specified by:

getText in interface EPStatement

Returns:

expression text

getName

public java.lang.String getName()

Description copied from interface: EPStatement

Returns the statement name.

Specified by:

getName in interface EPStatement

Returns:

statement name

iterator

public java.util.Iterator<EventBean> iterator(ContextPartitionSelector selector)

Description copied from interface: EPStatement

For use with statements that have a context declared and that may therefore have multiple context partitions, allows to iterate over context partitions selectively.

Specified by:

iterator in interface EPStatement

Parameters:

selector - selects context partitions to consider

Returns:

iterator

safeIterator

public SafeIterator<EventBean> safeIterator(ContextPartitionSelector selector)

Description copied from interface: EPStatement

For use with statements that have a context declared and that may therefore have multiple context partitions, allows to safe-iterate over context partitions selectively.

Specified by:

safeIterator in interface EPStatement

Parameters:

selector - selects context partitions to consider

Returns:

safe iterator

iterator

public java.util.Iterator<EventBean> iterator()

Description copied from interface: EPIterable

Returns a concurrency-unsafe iterator over events representing statement results (pull API).

The iterator is useful for applications that are single-threaded, or that coordinate the iterating thread with event processing threads that use the sendEvent method using application code locks or synchronization.

The iterator returned by this method does not make any guarantees towards correctness of results and fail-behavior, if your application processes events into the engine instance using the sendEvent method by multiple threads.

Use the safeIterator method for concurrency-safe iteration. Note the safe iterator requires applications to explicitly close the safe iterator when done iterating.

Specified by:

iterator in interface EPIterable

Returns:

event iterator

safeIterator

public SafeIterator<EventBean> safeIterator()

Description copied from interface: EPIterable

Returns a concurrency-safe iterator that iterates over events representing statement results (pull API) in the face of concurrent event processing by further threads.

In comparison to the regular iterator, the safe iterator guarantees correct results even as events are being processed by other threads. The cost is that the iterator holds one or more locks that must be released via the close method. Any locks are acquired at the time this method is called.

This method is a blocking method. It may block until statement processing locks are released such that the safe iterator can acquire any required locks.

An application MUST explicitly close the safe iterator instance using the close method, to release locks held by the iterator. The call to the close method should be done in a finally block to make sure the iterator gets closed.

Multiple safe iterators may be not be used at the same time by different application threads. A single application thread may hold and use multiple safe iterators however this is discouraged.

Specified by:

safeIterator in interface EPIterable

Returns:

safe iterator; NOTE: Must use the close method to close the safe iterator, preferably in a finally block

getEventType

public EventType getEventType()

Description copied from interface: EPIterable

Returns the type of events the iterable returns.

Specified by:

getEventType in interface EPIterable

Returns:

event type of events the iterator returns

getListenerSet

public EPStatementListenerSet getListenerSet()

Returns the set of listeners to the statement.

Specified by:

getListenerSet in interface EPStatementSPI

Returns:

statement listeners

setListeners

public void setListeners(EPStatementListenerSet listenerSet,
                         boolean isRecovery)

Description copied from interface: EPStatementSPI

Sets the statement listeners.

Care must be taken in the use of this method as unsynchronized modification to the listeners of a statement can yield problems.

Specified by:

setListeners in interface EPStatementSPI

Parameters:

listenerSet - set

addListener

public void addListener(UpdateListener listener)

Add a listener to the statement.

Specified by:

addListener in interface EPListenable

Parameters:

listener - to add

addListenerWithReplay

public void addListenerWithReplay(UpdateListener listener)

Description copied from interface: EPStatement

Add an update listener replaying current statement results to the listener.

The listener receives current statement results as the first call to the update method of the listener, passing in the newEvents parameter the current statement results as an array of zero or more events. Subsequent calls to the update method of the listener are statement results.

Current statement results are the events returned by the iterator or safeIterator methods.

Delivery of current statement results in the first call is performed by the same thread invoking this method, while subsequent calls to the listener may deliver statement results by the same or other threads.

Note: this is a blocking call, delivery is atomic: Events occurring during iteration and delivery to the listener are guaranteed to be delivered in a separate call and not lost. The listener implementation should minimize long-running or blocking operations.

Delivery is only atomic relative to the current statement. If the same listener instance is registered with other statements it may receive other statement result s simultaneously.

If a statement is not started an therefore does not have current results, the listener receives a single invocation with a null value in newEvents.

Specified by:

addListenerWithReplay in interface EPStatement

Parameters:

listener - to add

removeListener

public void removeListener(UpdateListener listener)

Remove a listeners to a statement.

Specified by:

removeListener in interface EPListenable

Parameters:

listener - to remove

removeAllListeners

public void removeAllListeners()

Remove all listeners to a statement.

Specified by:

removeAllListeners in interface EPListenable

addListener

public void addListener(StatementAwareUpdateListener listener)

Description copied from interface: EPListenable

Add a statement-aware listener that observes events.

Specified by:

addListener in interface EPListenable

Parameters:

listener - to add

removeListener

public void removeListener(StatementAwareUpdateListener listener)

Description copied from interface: EPListenable

Remove a statement-aware listener that observes events.

Specified by:

removeListener in interface EPListenable

Parameters:

listener - to remove

getStatementAwareListeners

public java.util.Iterator<StatementAwareUpdateListener> getStatementAwareListeners()

Description copied from interface: EPListenable

Returns an iterator of statement-aware update listeners.

The returned iterator does not allow the remove operation.

Specified by:

getStatementAwareListeners in interface EPListenable

Returns:

iterator of statement-aware update listeners

getUpdateListeners

public java.util.Iterator<UpdateListener> getUpdateListeners()

Description copied from interface: EPListenable

Returns an iterator of update listeners.

The returned iterator does not allow the remove operation.

Specified by:

getUpdateListeners in interface EPListenable

Returns:

iterator of update listeners

getTimeLastStateChange

public long getTimeLastStateChange()

Description copied from interface: EPStatement

Returns the system time in milliseconds of when the statement last change state.

Specified by:

getTimeLastStateChange in interface EPStatement

Returns:

time in milliseconds of last statement state change

isStarted

public boolean isStarted()

Description copied from interface: EPStatement

Returns true if the statement state is started.

Specified by:

isStarted in interface EPStatement

Returns:

true for started statements, false for stopped or destroyed statements.

isStopped

public boolean isStopped()

Description copied from interface: EPStatement

Returns true if the statement state is stopped.

Specified by:

isStopped in interface EPStatement

Returns:

true for stopped statements, false for started or destroyed statements.

isDestroyed

public boolean isDestroyed()

Description copied from interface: EPStatement

Returns true if the statement state is destroyed.

Specified by:

isDestroyed in interface EPStatement

Returns:

true for destroyed statements, false for started or stopped statements.

setSubscriber

public void setSubscriber(java.lang.Object subscriber)

Description copied from interface: EPStatement

Attaches a subscriber to receive statement results, or removes a previously set subscriber (by providing a null value).

Only a single subscriber may be set for a statement. If this method is invoked twice any previously-set subscriber is no longer used.

Specified by:

setSubscriber in interface EPStatement

Parameters:

subscriber - to attach, or null to remove the previously set subscriber

setSubscriber

public void setSubscriber(java.lang.Object subscriber,
                          java.lang.String methodName)

Description copied from interface: EPStatement

Attaches a subscriber to receive statement results by calling the method with the provided method name, or removes a previously set subscriber (by providing a null value).

Only a single subscriber may be set for a statement. If this method is invoked twice any previously-set subscriber is no longer used.

Specified by:

setSubscriber in interface EPStatement

Parameters:

subscriber - to attach, or null to remove the previously set subscriber

methodName - the name of the method to invoke, or null for the "update" method

getSubscriber

public java.lang.Object getSubscriber()

Description copied from interface: EPStatement

Returns the current subscriber instance that receives statement results.

Specified by:

getSubscriber in interface EPStatement

Returns:

subscriber object, or null to indicate that no subscriber is attached

isPattern

public boolean isPattern()

Description copied from interface: EPStatement

Returns true if statement is a pattern

Specified by:

isPattern in interface EPStatement

Returns:

true if statement is a pattern

getStatementMetadata

public StatementMetadata getStatementMetadata()

Description copied from interface: EPStatementSPI

Returns additional metadata about a statement.

Specified by:

getStatementMetadata in interface EPStatementSPI

Returns:

statement metadata

getUserObject

public java.lang.Object getUserObject()

Description copied from interface: EPStatement

Returns the application defined user data object associated with the statement, or null if none was supplied at time of statement creation.

The user object is a single, unnamed field that is stored with every statement. Applications may put arbitrary objects in this field or a null value.

User objects are passed at time of statement creation as a parameter the create method.

Specified by:

getUserObject in interface EPStatement

Returns:

user object or null if none defined

getAnnotations

public java.lang.annotation.Annotation[] getAnnotations()

Description copied from interface: EPStatement

Returns EPL or pattern statement annotations provided in the statement text, if any.

See the annotation com.espertech.esper.client.annotation package for available annotations.

Specified by:

getAnnotations in interface EPStatement

Returns:

annotations or a zero-length array if no annotaions have been specified.

getStatementContext

public StatementContext getStatementContext()

Description copied from interface: EPStatementSPI

Returns the statement context.

Specified by:

getStatementContext in interface EPStatementSPI

Returns:

statement context

getExpressionNoAnnotations

public java.lang.String getExpressionNoAnnotations()

Description copied from interface: EPStatementSPI

Returns the statements expression without annotations.

Specified by:

getExpressionNoAnnotations in interface EPStatementSPI

Returns:

expression

getServiceIsolated

public java.lang.String getServiceIsolated()

Description copied from interface: EPStatement

Returns the name of the isolated service provided is the statement is currently isolated in terms of event visibility and scheduling, or returns null if the statement is live in the engine.

Specified by:

getServiceIsolated in interface EPStatement

Returns:

isolated service name or null for statements that are not currently isolated

setServiceIsolated

public void setServiceIsolated(java.lang.String serviceIsolated)

Description copied from interface: EPStatementSPI

Set the statement's isolated service name, or null to clear.

Specified by:

setServiceIsolated in interface EPStatementSPI

Parameters:

serviceIsolated - name of isolated service

isNameProvided

public boolean isNameProvided()

Description copied from interface: EPStatementSPI

True if an explicit statement name has been provided, false if the statement name is system-generated.

Specified by:

isNameProvided in interface EPStatementSPI

Returns:

indicator if statement name exists