JavaECS-Docs/docs/system/system.md

*[JavaECS](../../README.md) / [docs](../overview.md) / system*
# System

### Contents
[About](#About)

[Implementation](#Implementation)

[Examples](#Examples)

## About
The system runs operations that must be performed on its assoiciated components.

Typically, this is expected to be run every frame, though this is not a strict requirement.

Examples of the `system` include the `health_system`; which reads the value of the entitie's `health` component and ensures h > 0.
``` java
void health_system(){
    for (i = 0; i < registeredComponents.size(); i++){
        if (registeredComponents[i].health <= 0){
            registeredComponents[i].dead = true;
            if (registeredComponents[i].isPlayer){
                GameOver();
            }
        }
    }
}
```
## Implementation

The systems are managed by the following code:

``` java
class SystemManager{
    ECS baseECS;
    int systemIndex;

    public SystemManager(ECS baseECS){
        this.baseECS = baseECS;
        systemIndex = 0;
    }
}
```

## Examples