/**
* 进入一个活跃状态，如果状态是原子状态，添加到当前的states Enter an active state If the state is atomic also record it add
* it to the current states
*
* @param state state to enter
*/
public void enterState(final EnterableState state) {
if (!activeStates.add(state)) {
throw new IllegalStateException("State " + state.getId() + " already added.");
}
if (state.isAtomicState()) {
if (!atomicStates.add(state)) {
throw new IllegalStateException("Atomic state " + state.getId() + " already added.");
}
}
}
