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com.oracle.cep.shell
Interface EpnCommand

public interface EpnCommand

Commands for manipulating EPN components.

A command is a high-level interface that abstracts the Java API. For instance, the channel command creates an EventChannel without the user having to go through an EventChannelFactory. A session must be commenced by invoking beginSession() before any commands can be issued. When done, a session must be ended by invoking endSession(). Ending a session destroys all EPN components that were created during the session. A session is not multithread aware, and must be synchronized by client. The EPN commands are issued through the OCEP shell. See documentation on how to start the shell. The OCEP shell commands are:

• begin
• end
• channel
• channels
• statements
• send
• insert
• update
• delete
• heartbeat
• eventtypes
• remove
• query
• view

The following variables can also be set for an EPN session:

• OUT_TIME: (FORMATTED) | PLAIN | OFF

For example, you can turn off including the time-stamp of the output events by using the following shell command: OUT_TIME=OFF Further, you may make use of the EPN commands in a regular OCEP application. This is done by retrieving the EpnCommand OSGi service. This services is registered as an OSGi service factory, thus each OCEP application gets a separate service object. This is ideal for creating Junit-like test-cases for testing EPNs and CQL statements. However, only the commands exposed in this class as methods can be used for this latter purpose.

Field Summary

static OutputTimeFormat	DEFAULT_TIME_FORMAT Default time format for output events.
static java.lang.String	OUTPUT_TIME_FORMAT_VAR_NAME Session variable that indicates format of time-stamp to be included in the output events.

Method Summary
void	beginSession() Begins a new session for invoking commands.
EventChannel	createChannel(boolean relation, java.lang.String applicationTimestampProp, boolean totalOrder, java.lang.String channelName, java.lang.Class clazz) Creates a new channel using a Java class event-type.
EventChannel	createChannel(boolean relation, java.lang.String applicationTimestampProp, boolean totalOrder, java.lang.String channelName, java.util.Map metadata) Creates a new channel using a metadata-based event-type.
EventChannel	createChannel(boolean relation, java.lang.String channelName, java.lang.Class clazz) Creates a new system timestamped channel using a Java class event-type.
EventChannel	createChannel(boolean relation, java.lang.String channelName, java.util.Map metadata) Creates a new system timestamped channel using a metadata-based event-type.
MapEventObject	createMapEvent(EventChannel channel, java.util.Map event) Creates a map-event to be used for metadata-based channels.
Processor	createProcessor(java.lang.String processorName) Creates a CQL processor in the current session.
Statement	createQuery(Processor processor, java.lang.String id, java.lang.String statementValue) Creates a CQL query.
Statement	createView(Processor processor, java.lang.String id, java.lang.String statementValue) Creates a CQL view.
void	endSession() Ends the current session.
EventChannel[]	getChannels() Returns all channels that have been created in this current session.
Processor[]	getProcessors() Returns all processors that have been created in this session.
StreamSource	link(StreamSource fromStage, StreamSink toStage) Connects the fromStage to the toStage.

Field Detail

OUTPUT_TIME_FORMAT_VAR_NAME

public static final java.lang.String OUTPUT_TIME_FORMAT_VAR_NAME

Session variable that indicates format of time-stamp to be included in the output events.

See Also:

OutputTimeFormat

DEFAULT_TIME_FORMAT

public static final OutputTimeFormat DEFAULT_TIME_FORMAT

Default time format for output events.

Method Detail

beginSession

public void beginSession()
                  throws java.lang.Exception,
                         java.lang.IllegalStateException

Begins a new session for invoking commands. Only a single session may be active at a time.

Throws:

java.lang.Exception - if session cannot be commenced.

java.lang.IllegalStateException - if a session already exists.

endSession

public void endSession()
                throws java.lang.IllegalStateException

Ends the current session. Only a single session may be active at a time.

Throws:

java.lang.IllegalStateException - if no session has been commenced.

getChannels

public EventChannel[] getChannels()
                           throws java.lang.IllegalStateException

Returns all channels that have been created in this current session.

Returns:

EventChannel [] list of channels in current session

Throws:

java.lang.IllegalStateException - if no session has been commenced.

createChannel

public EventChannel createChannel(boolean relation,
                                  java.lang.String channelName,
                                  java.lang.Class clazz)
                           throws java.lang.Exception,
                                  java.lang.IllegalStateException

Creates a new system timestamped channel using a Java class event-type.

Parameters:

relation - true if channel is a relation, false if it is a stream

channelName - name of the channel

clazz - event-type of the channel

Returns:

EventChannel

Throws:

java.lang.Exception - if channel cannot be created.

java.lang.IllegalStateException - if no session has been commenced.

createChannel

public EventChannel createChannel(boolean relation,
                                  java.lang.String applicationTimestampProp,
                                  boolean totalOrder,
                                  java.lang.String channelName,
                                  java.lang.Class clazz)
                           throws java.lang.Exception,
                                  java.lang.IllegalStateException

Creates a new channel using a Java class event-type. If channel is application timestamped, then event must include a timestamp.

Parameters:

relation - true if channel is a relation, false if it is a stream

applicationTimestampProp - name of the event property that should be used as the application timestamp, or null if channel is system timestamped.

totalOrder - true if application time is always strictly greater than the last value used.

channelName - name of the channel

clazz - event-type of the channel

Returns:

EventChannel

Throws:

java.lang.Exception - if channel cannot be created.

java.lang.IllegalStateException - if no session has been commenced.

createChannel

public EventChannel createChannel(boolean relation,
                                  java.lang.String channelName,
                                  java.util.Map metadata)
                           throws java.lang.Exception,
                                  java.lang.IllegalStateException

Creates a new system timestamped channel using a metadata-based event-type.

Parameters:

relation - true if channel is a relation, false if it is a stream

channelName - name of the channel

metadata - metadata describing the channel's event-type.

Returns:

EventChannel

Throws:

java.lang.Exception - if channel cannot be created.

java.lang.IllegalStateException - if no session has been commenced.

createChannel

public EventChannel createChannel(boolean relation,
                                  java.lang.String applicationTimestampProp,
                                  boolean totalOrder,
                                  java.lang.String channelName,
                                  java.util.Map metadata)
                           throws java.lang.Exception,
                                  java.lang.IllegalStateException

Creates a new channel using a metadata-based event-type. If channel is application time-stamped, then event must include a timestamp.

Parameters:

relation - true if channel is a relation, false if it is a stream

applicationTimestampProp - name of the event property that should be used as the application timestamp, or null if channel is system time-stamped.

totalOrder - true if application time is always strictly greater than the last value used.

channelName - name of the channel

metadata - metadata describing the channel's event-type.

Returns:

EventChannel

Throws:

java.lang.Exception - if channel cannot be created.

java.lang.IllegalStateException - if no session has been commenced.

getProcessors

public Processor[] getProcessors()
                          throws java.lang.IllegalStateException

Returns all processors that have been created in this session.

Returns:

Processor [] processors created in current session.

Throws:

java.lang.IllegalStateException - if no session has been commenced.

createProcessor

public Processor createProcessor(java.lang.String processorName)
                          throws java.lang.Exception,
                                 java.lang.IllegalStateException

Creates a CQL processor in the current session.

Parameters:

processorName - name of the processor

Returns:

Processor

Throws:

java.lang.Exception - if processor cannot be created

java.lang.IllegalStateException - if no session has been commenced.

link

public StreamSource link(StreamSource fromStage,
                         StreamSink toStage)
                  throws java.util.TooManyListenersException,
                         java.lang.IllegalStateException,
                         java.lang.Exception

Connects the fromStage to the toStage.

Parameters:

fromStage - the event source

toStage - the event sink

Returns:

the event source

Throws:

java.util.TooManyListenersException - if fromStage cannot be added another event sink

java.lang.Exception - if link cannot be created

java.lang.IllegalStateException - if no session has been commenced.

createView

public Statement createView(Processor processor,
                            java.lang.String id,
                            java.lang.String statementValue)
                     throws java.lang.IllegalStateException,
                            java.lang.IllegalArgumentException

Creates a CQL view.

Parameters:

processor - the source processor

id - the ID of the view

statementValue - the value of the view

Returns:

Statement CQL view

Throws:

java.lang.IllegalStateException - if no session has been commenced.

java.lang.IllegalArgumentException - if processor was not created in the current session.

createQuery

public Statement createQuery(Processor processor,
                             java.lang.String id,
                             java.lang.String statementValue)
                      throws java.lang.IllegalStateException,
                             java.lang.IllegalArgumentException

Creates a CQL query.

Parameters:

processor - the source processor

id - the ID of the view

statementValue - the value of the view

Returns:

Statement CQL view

Throws:

java.lang.IllegalStateException - if no session has been commenced.

java.lang.IllegalArgumentException - if processor was not created in the current session.

createMapEvent

public MapEventObject createMapEvent(EventChannel channel,
                                     java.util.Map event)

Creates a map-event to be used for metadata-based channels.

Parameters:

channel - targeted channel

event - map-based event

Returns:

event Map-based event