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https://github.com/tareqk/easybus
Simple, No Frills Event Bus for Java
https://github.com/tareqk/easybus
Last synced: 11 days ago
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Simple, No Frills Event Bus for Java
- Host: GitHub
- URL: https://github.com/tareqk/easybus
- Owner: TareqK
- License: mit
- Created: 2020-05-29T15:25:05.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2024-08-03T16:48:42.000Z (5 months ago)
- Last Synced: 2024-08-03T18:00:10.573Z (5 months ago)
- Language: Java
- Homepage:
- Size: 168 KB
- Stars: 3
- Watchers: 2
- Forks: 2
- Open Issues: 3
-
Metadata Files:
- Readme: README.MD
- License: LICENSE
Awesome Lists containing this project
README
# EasyBus
Easy bus is a simple, strictly typed event bus for java designed for simplicity
and minimalism.
# Usage
## Installation
To use the easybus, add the following into your pom.xml
```xml
me.kisoft
easybus-core
${LATEST_VERSION}
```
If you want to use a specific backing implementation of easybus, you can also import
that specific implementation which will also import easybus
## Defining Events and Listeners
Afterwards, you will need to define your events and listeners. Events are simply
POJOs(preferably Beans) and listeners are classes that implement ``Listener``. A Listener
may only listen for a single event(and its subclasses) - this is due to type erasure in
java for generics that disallows multi inheritance.
### Defining Events
```java
public class MyEvent{
// members and code here
}
```
### Defining Listeners
```java
public class MyEventListener implements Listener{
@Override
public void on(MyEvent event){
// your code here
}
}
```
### Adding Listeners
```java
EasyBus bus = new EasyBus();
bus.register(new MyEventListener());
```
You will also probably need to wrap the event bus as a singleton or
maintain some reference to it, but thats up to the programmer.
### Activation/DI
If you want to use DI in your event listeners, you can do that by passing a custom
activator to easybus on creation.
The activator is a functional interface that takes a class that extends ``Listener``
and returns a new instance.
In this example, we assume you are using ``Guice`` as your DI provider
```java
EasyBus bus = new EasyBus(injector::getInstance);
bus.register(MyEventListenerUsingDI.class);
```
by default, the built in activator attempts to call a no-args constructor.
### Posting Events
```java
bus.post(new MyEvent());
```
### Handle Async
The default in-memory event bus(which is also used as a utility internal bus for other implementations)
can either process events in the current thread or delegate it to a thread pool. To mark an event
as delegated to a thread pool, use the ``@ProcessAsync`` annotation on the event class
```java
@ProcessAsync
public class MyAsyncEvent{
}
```
Note that any errors that happen when processing this event are ignored, and as such, its
highly advised to only use this sparingly.
## Implementing a Backing Bus
To implement a backing bus, all you need to do is implement the ``me.kisoft.easybus.BackingBus`` Interface, and when
creating a new EasyBus, you need to use the ``new EasyBus(BackingBus bus)`` constructor to change the backing bus, or
create your own factory