com.fluxtion.runtime.event.Event Maven / Gradle / Ivy
/*
* Copyright (C) 2019 2024 gregory higgins.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* .
*/
package com.fluxtion.runtime.event;
import com.fluxtion.runtime.node.EventHandlerNode;
import com.fluxtion.runtime.annotations.OnEventHandler;
/**
*
* Event class that feeds into a Simple Event Processor(SEP) providing additional
* meta-data about the incoming event. The additional data provided is:
*
*
* - Filtering
* - Event creation time
*
*
* Dispatch
* A user creates an Event and publishes it to a SEP for handling via the
* {@link com.fluxtion.runtime.StaticEventProcessor#onEvent(Object)} method.
*
* To dispatch the events within the SEP Fluxtion uses the class name to perform
* a dispatch. When class name is used, uniqueness is guaranteed by using the
* fully qualified class name.
*
*
* Filtering
*
* An event can provide a filter field as either an int or a String, this allow
* {@link EventHandlerNode}'s or annotated event handler methods to filter
* the type of events they receive. The SEP will compare the filter values in
* the {@link Event} and the handler and propagate the Event conditional upon a
* valid match.
*
* @author 2024 gregory higgins.
* @see OnEventHandler
* @see EventHandlerNode
*/
public interface Event {
int NO_INT_FILTER = Integer.MAX_VALUE;
String NO_STRING_FILTER = "";
/**
* The integer id of a filter for this event, can be used interchangeably
* with filterString. The event handler decides whether it will filter using
* Strings or integer's, calling this method if filtering is integer based.
* Integer filtering will generally be more efficient than string filtering,
* but this depends upon the underlying target platform processing
* characteristics.
*
* @return optional event filter id as integer
*/
default int filterId() {
return NO_INT_FILTER;
}
/**
* The String id of a filter for this event, can be used interchangeably
* with filterId. The event handler decides whether it will filter using
* Strings or integer's, calling this method if String filtering is string
* based. Integer filtering will generally be more efficient than string
* filtering, but this depends upon the underlying target platform
* processing characteristics.
*
* @return optional event filter id as String
*/
default String filterString() {
return NO_STRING_FILTER;
}
/**
* The time the event was created. By default this is implemented with {@link System#currentTimeMillis()
* } during construction.
*
* @return creation time, if less than 0 no time of creation is recorded
*/
default long getEventTime() {
return -1;
}
}