net.openhft.chronicle.wire.Event Maven / Gradle / Ivy
/*
* Copyright (c) 2016-2020 chronicle.software
*/
package net.openhft.chronicle.wire;
import org.jetbrains.annotations.NotNull;
/**
* This interface defines the structure and behavior of an event within a system.
* It extends {@link BaseEvent}, thereby inheriting methods related to time management,
* and adds methods specific to event identification and manipulation.
*
* NOTE: Only use this interface if the eventId is required as the eventTime is sufficient in most cases
*
* @param The type of the implementing event class, following the self-referential generic pattern.
*/
public interface Event> extends BaseEvent {
/**
* Retrieves the unique identifier associated with this event.
*
* @return The unique identifier for this event.
*/
@NotNull
default CharSequence eventId() {
// Return an empty string as the default event ID
return "";
}
/**
* Assigns an identifier to this event. The provided identifier must not be null.
* This method can be used to explicitly set or change the event's identifier.
*
* @param eventId The unique identifier to assign to this event.
* @return The current instance of the event, facilitating method chaining.
*/
@SuppressWarnings("unchecked")
default E eventId(@NotNull final CharSequence eventId) {
// By default, the event identifier is unchanged and the current instance is returned.
return (E) this;
}
/**
* Updates the event with a new name, and if the event time is not already set,
* updates the event time to the current system time. This method is useful for renaming
* events and ensuring they have a valid timestamp.
*
* @param eventName The new name to be assigned to the event.
* @return The current instance of the implementing class, with any necessary updates applied.
*/
@SuppressWarnings("unchecked")
default E updateEvent(final String eventName) {
// Set the event ID to the given name if it's currently unset
if (this.eventId().length() == 0)
this.eventId(eventName);
// Update the event time to the current system time if it's currently unset
if (this.eventTime() <= 0)
this.eventTimeNow();
return (E) this;
}
/**
* Copies essential details from one event to another. This method is preferred over direct
* field access as it provides a more controlled way of transferring details between events,
* and facilitates future changes to the event structure.
*
* @param from The source event from which details are copied.
* @param to The target event to which details are copied.
*/
static void copyEventDetails(Event from, Event to) {
to.eventId(from.eventId());
to.eventTime(from.eventTime());
}
}