1. Michael Ludwig
  2. entreri


entreri / README.md


Entreri is a data-oriented entity-component framework designed for high performance applications and games. It scales well to tens of thousands of instances, in both memory and performance, and fits data models that require many similar objects of the same type, objects with composable types at runtime, and combinations thereof.

Using annotations and minor limitations to type definitions, component data is packed into primitive arrays to improve cache locality. Fly-weight instances are then used to access the packed data.

Java's garbage collection can move objects around, hurting locality when using Object arrays or collections. By using primitive arrays or buffers storing managed data in blocks, all of your game data will be automatically stored in a cache friendly, and iteration friendly manner.

In addition, this requires less memory per instance because the actual component data is stored in packed structures, avoiding the Java Object model overhead normally associated with complex classes.

In off-the-cuff performance tests, garbage collection in other entity-component frameworks could cause performance to slow down by a factor of 2 to 4, while Entreri remained consistently fast (pre-GC performances near identical).


Entreri can be easily added to a Maven project with the XML snippet below. The Eclipse plugin, m2e, can be used for Maven/Eclipse integration.


Release Notes


  • Improve performance in default Property implementations by restricting them to a single primitive per component (removing a multiply and add on access).
  • Expose multi-element supporting IndexedDataStores that were previously hidden inside the provided Property implementations.
  • Simplify Phase enum and usage to not need ALL value.
  • Fix bug with time delta calculation.
  • Improve Result API in ControllerManage to not cause a type explosion.
  • Add @Clone attribute to allow more flexibility in PropertyFactory.clone() without requiring you to implement an entire PropertyFactory.


  • Improve PropertyFactory API to better support custom Property definitions that want to define new annotations to control default behavior, etc.
  • Replace Controller data storage using Key objects with a simple Result API that allows Controllers to express interest in data and have that injected using custom interfaces defined by the computing controller.


  • Add protected onSet(int) method to ComponentData to better support ComponentData's that rely on unmanaged fields for caching.
  • Add functionality to estimate memory usage by component type.
  • Update ControllerManage to record run time performance of each controller, for the last executed frame.
  • Changed the no-argument process() method in ControllerManager to use the real change in time from the last frame, instead of a fixed time delta.