de.aristaflow.adept2.core.eventmanager.fileevents

Class InstanceStartEventHandler

java.lang.Object

de.aristaflow.adept2.core.eventmanager.common.AbstractEventHandler

de.aristaflow.adept2.core.eventmanager.fileevents.InstanceStartEventHandler

All Implemented Interfaces:

EventHandler

@ConfigurationDescription(properties={@Property(name="IsCritical",type=BOOLEAN,defaultValue="true",description="Whether the event handler is critical and problems handling the event should abort all handling of the current event."),,})
public class InstanceStartEventHandler
extends AbstractEventHandler

An event handler for file events, that stores data from an occurred file event as input parameters in the data container of an instance and starts this instance afterwards.
The input parameters need to have specific names to allow for setting the values according to the file.

Author:

Ulrich Kreher, Marco Waimer

Field Summary

Fields

Modifier and Type	Field and Description
protected static java.lang.String	CONF_IS_CRITICAL Configuration key: Whether the event handler is critical and problems handling the event should abort all handling of the current event.
protected static java.lang.String	CONF_PROCESS_TYPE Configuration key: The process type of which to start the "latest" template in case the appropriate event occurs.
protected DefaultEventManager	eventManager The event manager for communicating with the runtime service.
static java.lang.String	PARAM_FILE Process parameter name for the file.
static java.lang.String	PARAM_FILENAME Process parameter name for the file name.
static java.lang.String	PARAM_LOCK_FILE Process parameter name for the lock file.
static java.lang.String	PARAM_MODIFIED_DATE Process parameter name for the file name.
protected java.lang.String	processType The process type of which to start the "latest" template in case the appropriate event occurs.
protected TemplateReference	template The template which to instantiate in case an appropriate mail event occurs.

Fields inherited from class de.aristaflow.adept2.core.eventmanager.common.AbstractEventHandler

consuming, critical, exclusive, id, interruptible, logger

Constructor Summary

Constructors

Constructor and Description
InstanceStartEventHandler(Configuration conf, DefaultEventManager eventManager, Registry registry) Creates a new handler for file events that starts instances and stores data from the file in the instance input parameters.

Method Summary

Modifier and Type	Method and Description
protected TemplateReference	getAndCheckTemplate(SessionToken session) Retrieves the "latest" template of the configured process type and checks for whether it has the right input parameter.
boolean	handleEvent(Event eve, boolean consumed) This method actually processes an event.
protected void	processFileEvent(FileEvent event, java.util.Collection<? extends Parameter> inParams, InstanceDataContainer dataContainer) Processes the file of the designated event and sets the values of the input parameters in the designated data container.

Methods inherited from class de.aristaflow.adept2.core.eventmanager.common.AbstractEventHandler

getID, isConsuming, isCritical, isExclusive, isInterruptible

Methods inherited from class java.lang.Object

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

Field Detail

CONF_IS_CRITICAL

protected static final java.lang.String CONF_IS_CRITICAL

Configuration key: Whether the event handler is critical and problems handling the event should abort all handling of the current event.

See Also:

Constant Field Values

CONF_PROCESS_TYPE

protected static final java.lang.String CONF_PROCESS_TYPE

Configuration key: The process type of which to start the "latest" template in case the appropriate event occurs.

See Also:

Constant Field Values

processType

protected final java.lang.String processType

The process type of which to start the "latest" template in case the appropriate event occurs.

template

protected TemplateReference template

The template which to instantiate in case an appropriate mail event occurs. This will be temporarily set to null if there are problems instantiating it.

eventManager

protected final DefaultEventManager eventManager

The event manager for communicating with the runtime service.

PARAM_FILENAME

public static final java.lang.String PARAM_FILENAME

Process parameter name for the file name.

See Also:

Constant Field Values

PARAM_MODIFIED_DATE

public static final java.lang.String PARAM_MODIFIED_DATE

Process parameter name for the file name.

See Also:

Constant Field Values

PARAM_FILE

public static final java.lang.String PARAM_FILE

Process parameter name for the file.

See Also:

Constant Field Values

PARAM_LOCK_FILE

public static final java.lang.String PARAM_LOCK_FILE

Process parameter name for the lock file.

See Also:

Constant Field Values

Constructor Detail

InstanceStartEventHandler

public InstanceStartEventHandler(Configuration conf,
                                 DefaultEventManager eventManager,
                                 Registry registry)
                          throws ConfigurationException

Creates a new handler for file events that starts instances and stores data from the file in the instance input parameters.

Parameters:

conf - The configuration for this plugin instance.

eventManager - The event manager for starting the process instance.

registry - The registry for retrieving the plugin instance name (handler ID).

Throws:

ConfigurationException - If there are problems creating the configured file store or writing to it or the template cannot be retrieved or has the wrong input parameter, a ConfigurationException will be thrown.

Method Detail

handleEvent

public boolean handleEvent(Event eve,
                           boolean consumed)
                    throws EventHandlingException

Description copied from interface: EventHandler

This method actually processes an event. What is done depends on the implementation of the event handler. Some restrictions may apply depending on the produced event. Only events will be received for which the event handler is registered. However, to improve robustness, an event handler should check the event before processing. If it cannot handle the provided event, this method should just return.
Event handling is usually synchronously, that is, this method will only be executed by one thread at a time. If another event of the same type occurs while still handling the previous event, the second event will be suspended until the previous event has been completely handled. There is no need to start a separate thread while handling to improve performance. But it is not forbidden to do so. Handling that takes place in a new thread is not exclusive any more and therefore must not consume the event!

Parameters:

eve - The event that occurred and for which this event handler is registered.

consumed - Whether the event has been consumed by a previous event handler.

Returns:

Whether the event has been consumed (that is changed) while handling it. If the event has been consumed before the current handing, it will have to remain consumed (implementations must return true).

Throws:

EventHandlingException - If there have been problems handling the event, an EventHandlingException may be thrown. If this is critical, the event handling for the current event will stop. If it is non-critical, other event handlers will also get the event for handling it.
If event handling fails, the corresponding event handler needs to roll back its changes, especially a consuming event handler.

getAndCheckTemplate

protected TemplateReference getAndCheckTemplate(SessionToken session)
                                         throws InvalidDataTypeException,
                                                NoSuchParameterException

Retrieves the "latest" template of the configured process type and checks for whether it has the right input parameter. An input parameter having the right name for a file event must be of the right data type and there must not be any mandatory input parameter that do not have an appropriate file event name.

Parameters:

session - The session token used to retrieve the "latest" template.

Returns:

The "latest" template of the configured process type or null in case the process type does not have a template.

Throws:

InvalidDataTypeException - If the template has an input parameter mapping to a file event (due to its name) but has the wrong type, an InvalidDataTypeException will be thrown.

NoSuchParameterException - If the template has a mandatory input parameter that does not map to a file event, a NoSuchParameterException will be thrown.

processFileEvent

protected void processFileEvent(FileEvent event,
                                java.util.Collection<? extends Parameter> inParams,
                                InstanceDataContainer dataContainer)
                         throws InvalidDataTypeException,
                                NoSuchParameterException,
                                java.io.IOException

Processes the file of the designated event and sets the values of the input parameters in the designated data container.

Parameters:

event - The event which to process and which provides the values for the input parameters.

inParams - The input parameters of the template.

dataContainer - The data container of the template in which to set the values.

Throws:

InvalidDataTypeException - If writing to the data container fails due to a provided input parameter having another type in the data container or a parameter has a wrong user-defined type, an InvalidDataTypeException will be thrown.

NoSuchParameterException - If writing to the data container fails due to a provided input parameter not being in the data container, a NoSuchParameterException will be thrown.

java.io.IOException - If creating the value for an UDT fails, an IOException will be thrown.