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<component type="playSound" trigger="touchedByPlayer" value="sound1.ogg"/>
<component type="removePowerFromMyself" trigger="touchedByShot" value="valueOfTheShot"/>

import com.artemis.Component;
import com.artemis.ComponentType;
import com.artemis.ComponentTypeManager;
import com.artemis.Entity;
import com.artemis.EntityProcessingSystem;

public abstract class CachedComponentsSystem extends EntityProcessingSystem {

    public static final int CAPACITY = 50000;
    private Component[][] sysComps;
    private ComponentType[] sysCompTypes;

    private Component[][] nonSysComps;
    private ComponentType[] nonSysCompTypes;

    public CachedComponentsSystem(Class<? extends Component>... systemComponents) {
        super(systemComponents);
        sysComps = new Component[systemComponents.length][];
        sysCompTypes = new ComponentType[systemComponents.length];
        for (int i = 0, s = systemComponents.length; i < s; i++) {
            sysComps[i] = new Component[CAPACITY];
            sysCompTypes[i] = ComponentTypeManager.getTypeFor(systemComponents[i]);
        }
        nonSysCompTypes = new ComponentType[0];
    }

    @Override
    public void initialize() {}

    /**
     * @param nonSystemComponents Components used by the system not required for an entity to register with the system.
     */
    protected void setNonSystemComponents(Class<? extends Component>... nonSystemComponents) {
        nonSysComps = new Component[nonSystemComponents.length][];
        nonSysCompTypes = new ComponentType[nonSystemComponents.length];
        for (int i = 0, s = nonSystemComponents.length; i < s; i++) {
            nonSysComps[i] = new Component[CAPACITY];
            nonSysCompTypes[i] = ComponentTypeManager.getTypeFor(nonSystemComponents[i]);
        }
    }

    @Override
    protected void added(Entity e) {
        for (int i = 0, s = sysCompTypes.length; i < s; i++) {
            sysComps[i][e.getId()] = e.getComponent(sysCompTypes[i]);
        }

        for (int i = 0, s = nonSysCompTypes.length; i < s; i++) {
            nonSysComps[i][e.getId()] = e.getComponent(nonSysCompTypes[i]);
        }
    }

    @Override
    protected void removed(Entity e) {
        for (int i = 0, s = sysCompTypes.length; i < s; i++) {
            sysComps[i][e.getId()] = null;
        }

        for (int i = 0, s = nonSysCompTypes.length; i < s; i++) {
            nonSysComps[i][e.getId()] = null;
        }
    }

    /**
     * @param compNumber 0-indexed component number as given in constructor
     * @param entityId entity id, typically from entity.getId()
     * @return Non-null component for the given entity, cached in the system
     */
    protected Component getSystemComponent(int compNumber, int entityId) {
        return sysComps[compNumber][entityId];
    }


    /**
     * @param compNumber 0-indexed component number as given in setNonSystemComponents
     * @param entityId entity id, typically from entity.getId()
     * @return Component for the given entiy, may be null
     */
    protected Component getNonSystemComponent(int compNumber, int entityId) {
        return nonSysComps[compNumber][entityId];
    }
}

import com.artemis.Entity;
import com.es.components.gamelogic.Lifespan;
import com.es.components.generic.CachedComponentsSystem;
import com.es.state.GameWorld;

public class LifespanSystem extends CachedComponentsSystem {

    public LifespanSystem() {
        super(Lifespan.class);
    }

    @Override
    protected void process(Entity entity) {
            Lifespan lifespan = (Lifespan) getSystemComponent(0, entity.getId());
            lifespan.lifespan -= world.getDelta();
            if (!lifespan.isAlive()) {
                ((GameWorld) world).expireEntity(entity);
            }
    }

}