/**
* 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.");
}
}
}
/**
* Exit an active state If the state is atomic also remove it from current states
*
* <p>退出一个活跃的状态，
*
* @param state state to exit
*/
public void exitState(final EnterableState state) {
if (!activeStates.remove(state)) {
throw new IllegalStateException("State " + state.getId() + " not active.");
}
atomicStates.remove(state);
}