The state machine pauses at the choice state when the evaluation inside the choice state returns false, instead of moving to the next state.
下面的代码：
国家定义：
@Override
public void configure(StateMachineStateConfigurer<String, String>
states) throws Exception {
states
.withStates()
.initial("init")
.choice("S1Choice")
.state("S1")
.choice("S2Choice")
.state("S2")
.choice("S3Choice")
.state("S3")
.state("end");
}
过渡/选择/动作：
@Override
public void configure(StateMachineTransitionConfigurer<String, String> transitions) throws Exception {
transitions
.withExternal()
.source("init")
.target("S1Choice")
.event("start")
.and()
.withChoice()
.source("S1Choice")
.first("S1", new Guard<String, String>() {
public boolean evaluate(StateContext<String, String> context) {
System.out.println("In s1 choice");
/*Map<Object, Object> map = context.getExtendedState().getVariables();
return !map.containsKey("S1done");*/
return false;
}
})
.last("S2Choice")
.and()
.withLocal()
.source("S1")
.target("S2Choice")
.action(new Action<String, String>() {
public void execute(StateContext<String, String> context) {
Map<Object, Object> map = context.getExtendedState().getVariables();
System.out.println("Executing s1");
map.put("S1done", Boolean.TRUE);
}
})
.and()
.withChoice()
.source("S2Choice")
.first("S2", new Guard<String, String>() {
public boolean evaluate(StateContext<String, String> context) {
System.out.println("In s2 choice");
Map<Object, Object> map = context.getExtendedState().getVariables();
return !map.containsKey("S2done");
}
})
.last("S3Choice")
.and()
.withLocal()
.source("S2")
.target("S3Choice")
.action(new Action<String, String>() {
public void execute(StateContext<String, String> context) {
Map<Object, Object> map = context.getExtendedState().getVariables();
System.out.println("Executing s2");
map.put("S2done", Boolean.TRUE);
}
})
.and()
.withChoice()
.source("S3Choice")
.first("S3", new Guard<String, String>() {
public boolean evaluate(StateContext<String, String> context) {
System.out.println("In s3 choice");
Map<Object, Object> map = context.getExtendedState().getVariables();
return !map.containsKey("S3done");
}
})
.last("end")
.and()
.withLocal()
.source("S3")
.target("end")
.and()
.withLocal()
.source("end")
.target("init");
}
主要类：
public static void main(String[] args) {
ApplicationContext context = new AnnotationConfigApplicationContext(TasksConfig.class);
StateMachine<String, String> stateMachine = context.getBean(StateMachine.class);
stateMachine.start();
stateMachine.getExtendedState().getVariables().put("S1done", Boolean.TRUE);
stateMachine.sendEvent("start");
//stateMachine.stop();
}
以下是捕获的输出示例：
工作项状态更改为 init
信息：开始 S2 S1 结束初始化 S3 S1Choice S3Choice S2Choice / init /
在 s1 选择
如您所见，它停在状态 -“s1 选择”而不是移动到新状态 -“s2 选择”。