[FEATURE]:[给状态机提供一些新操作接口]

1. 增加com.alibaba.cola.statemachine.StateMachine#verify方法用来判断当前状态能否响应某个事件 2. 增加com.alibaba.cola.statemachine.builder.StateMachineBuilder#setFailoverCallback 用来增加在状态流转没有命中当前配置的规则时执行的回调接口定义 com.alibaba.cola.statemachine.builder.FailoverCallback 默认为NumbFailoverCallbackImpl，与当前行为一样，什么都不做。另外内置AlertFailoverCallbackImpl，用于抛出异常TransitionFailoverException
Forgus · Sep 15, 2022 · e072976 · e072976
1 parent 3ac5b4e
commit e072976
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Showing 10 changed files with 215 additions and 65 deletions.
diff --git a/cola-components/cola-component-statemachine/pom.xml b/cola-components/cola-component-statemachine/pom.xml
@@ -8,6 +8,7 @@
     </parent>
 
     <artifactId>cola-component-statemachine</artifactId>
+    <version>4.4.1-SNAPSHOT</version>
     <packaging>jar</packaging>
     <name>${project.artifactId}</name>
     <description>${project.artifactId}</description>

diff --git a/...cola-component-statemachine/src/main/java/com/alibaba/cola/statemachine/StateMachine.java b/...cola-component-statemachine/src/main/java/com/alibaba/cola/statemachine/StateMachine.java
@@ -12,6 +12,14 @@
  */
 public interface StateMachine<S, E, C> extends Visitable{
 
+    /**
+     * Verify if an event {@code E} can be fired from current state {@code S}
+     * @param sourceStateId
+     * @param event
+     * @return
+     */
+    boolean verify(S sourceStateId,E event);
+
     /**
      * Send an event {@code E} to the state machine.
      *

diff --git a/...achine/src/main/java/com/alibaba/cola/statemachine/builder/AlertFailoverCallbackImpl.java b/...achine/src/main/java/com/alibaba/cola/statemachine/builder/AlertFailoverCallbackImpl.java
@@ -0,0 +1,18 @@
+package com.alibaba.cola.statemachine.builder;
+
+import com.alibaba.cola.statemachine.exception.TransitionFailoverException;
+
+/**
+ * Default failover callback, do nothing.
+ *
+ * @author 龙也
+ * @date 2022/9/15 12:02 PM
+ */
+public class AlertFailoverCallbackImpl<S, E, C> implements FailoverCallback<S, E, C> {
+
+    @Override
+    public void onFailover(S sourceState, E event, C context) {
+        throw new TransitionFailoverException(
+            "Cannot fire event [" + event + "] on current state [" + sourceState + "] with context [" + context + "]");
+    }
+}
diff --git a/...nt-statemachine/src/main/java/com/alibaba/cola/statemachine/builder/FailoverCallback.java b/...nt-statemachine/src/main/java/com/alibaba/cola/statemachine/builder/FailoverCallback.java
@@ -0,0 +1,18 @@
+package com.alibaba.cola.statemachine.builder;
+
+/**
+ * @author 龙也
+ * @date 2022/9/15 12:02 PM
+ */
+@FunctionalInterface
+public interface FailoverCallback<S, E, C> {
+
+    /**
+     * Callback function to execute on failover
+     *
+     * @param sourceState
+     * @param event
+     * @param context
+     */
+    void onFailover(S sourceState, E event, C context);
+}
diff --git a/...machine/src/main/java/com/alibaba/cola/statemachine/builder/NumbFailoverCallbackImpl.java b/...machine/src/main/java/com/alibaba/cola/statemachine/builder/NumbFailoverCallbackImpl.java
@@ -0,0 +1,15 @@
+package com.alibaba.cola.statemachine.builder;
+
+/**
+ * Default failover callback, do nothing.
+ *
+ * @author 龙也
+ * @date 2022/9/15 12:02 PM
+ */
+public class NumbFailoverCallbackImpl<S, E, C> implements FailoverCallback<S, E, C> {
+
+    @Override
+    public void onFailover(S sourceState, E event, C context) {
+        //do nothing
+    }
+}
diff --git a/...statemachine/src/main/java/com/alibaba/cola/statemachine/builder/StateMachineBuilder.java b/...statemachine/src/main/java/com/alibaba/cola/statemachine/builder/StateMachineBuilder.java
@@ -11,22 +11,32 @@
 public interface StateMachineBuilder<S, E, C> {
     /**
      * Builder for one transition
+     *
      * @return External transition builder
      */
     ExternalTransitionBuilder<S, E, C> externalTransition();
 
     /**
      * Builder for multiple transitions
+     *
      * @return External transition builder
      */
     ExternalTransitionsBuilder<S, E, C> externalTransitions();
 
     /**
      * Start to build internal transition
+     *
      * @return Internal transition builder
      */
     InternalTransitionBuilder<S, E, C> internalTransition();
 
-    StateMachine<S,E,C> build(String machineId);
+    /**
+     * set up failover callback, default do nothing {@code NumbFailoverCallbackImpl}
+     *
+     * @param callback
+     */
+    void setFailoverCallback(FailoverCallback<S, E, C> callback);
+
+    StateMachine<S, E, C> build(String machineId);
 
 }
diff --git a/...emachine/src/main/java/com/alibaba/cola/statemachine/builder/StateMachineBuilderImpl.java b/...emachine/src/main/java/com/alibaba/cola/statemachine/builder/StateMachineBuilderImpl.java
@@ -1,14 +1,14 @@
 package com.alibaba.cola.statemachine.builder;
 
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
 import com.alibaba.cola.statemachine.State;
 import com.alibaba.cola.statemachine.StateMachine;
 import com.alibaba.cola.statemachine.StateMachineFactory;
 import com.alibaba.cola.statemachine.impl.StateMachineImpl;
 import com.alibaba.cola.statemachine.impl.TransitionType;
 
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-
 /**
  * StateMachineBuilderImpl
  *
@@ -20,8 +20,9 @@ public class StateMachineBuilderImpl<S, E, C> implements StateMachineBuilder<S,
     /**
      * StateMap is the same with stateMachine, as the core of state machine is holding reference to states.
      */
-    private final Map<S, State< S, E, C>> stateMap = new ConcurrentHashMap<>();
+    private final Map<S, State<S, E, C>> stateMap = new ConcurrentHashMap<>();
     private final StateMachineImpl<S, E, C> stateMachine = new StateMachineImpl<>(stateMap);
+    private FailoverCallback<S, E, C> failoverCallback = new NumbFailoverCallbackImpl<>();
 
     @Override
     public ExternalTransitionBuilder<S, E, C> externalTransition() {
@@ -38,10 +39,16 @@ public InternalTransitionBuilder<S, E, C> internalTransition() {
         return new TransitionBuilderImpl<>(stateMap, TransitionType.INTERNAL);
     }
 
+    @Override
+    public void setFailoverCallback(FailoverCallback<S, E, C> callback) {
+        this.failoverCallback = callback;
+    }
+
     @Override
     public StateMachine<S, E, C> build(String machineId) {
         stateMachine.setMachineId(machineId);
         stateMachine.setReady(true);
+        stateMachine.setFailoverCallback(failoverCallback);
         StateMachineFactory.register(stateMachine);
         return stateMachine;
     }

diff --git a/...ne/src/main/java/com/alibaba/cola/statemachine/exception/TransitionFailoverException.java b/...ne/src/main/java/com/alibaba/cola/statemachine/exception/TransitionFailoverException.java
@@ -0,0 +1,12 @@
+package com.alibaba.cola.statemachine.exception;
+
+/**
+ * @author 龙也
+ * @date 2022/9/15 12:08 PM
+ */
+public class TransitionFailoverException extends RuntimeException {
+
+    public TransitionFailoverException(String errMsg) {
+        super(errMsg);
+    }
+}
diff --git a/...onent-statemachine/src/main/java/com/alibaba/cola/statemachine/impl/StateMachineImpl.java b/...onent-statemachine/src/main/java/com/alibaba/cola/statemachine/impl/StateMachineImpl.java
@@ -1,12 +1,13 @@
 package com.alibaba.cola.statemachine.impl;
 
+import java.util.List;
+import java.util.Map;
+
 import com.alibaba.cola.statemachine.State;
 import com.alibaba.cola.statemachine.StateMachine;
 import com.alibaba.cola.statemachine.Transition;
 import com.alibaba.cola.statemachine.Visitor;
-
-import java.util.List;
-import java.util.Map;
+import com.alibaba.cola.statemachine.builder.FailoverCallback;
 
 /**
  * For performance consideration,
@@ -26,17 +27,31 @@ public class StateMachineImpl<S, E, C> implements StateMachine<S, E, C> {
 
     private boolean ready;
 
+    private FailoverCallback<S, E, C> failoverCallback;
+
     public StateMachineImpl(Map<S, State<S, E, C>> stateMap) {
         this.stateMap = stateMap;
     }
 
+    @Override
+    public boolean verify(S sourceStateId, E event) {
+        isReady();
+
+        State sourceState = getState(sourceStateId);
+
+        List<Transition<S, E, C>> transitions = sourceState.getEventTransitions(event);
+
+        return transitions != null && transitions.size() != 0;
+    }
+
     @Override
     public S fireEvent(S sourceStateId, E event, C ctx) {
         isReady();
         Transition<S, E, C> transition = routeTransition(sourceStateId, event, ctx);
 
         if (transition == null) {
             Debugger.debug("There is no Transition for " + event);
+            failoverCallback.onFailover(sourceStateId, event, ctx);
             return sourceStateId;
         }
 
@@ -115,4 +130,8 @@ public void setMachineId(String machineId) {
     public void setReady(boolean ready) {
         this.ready = ready;
     }
+
+    public void setFailoverCallback(FailoverCallback<S, E, C> failoverCallback) {
+        this.failoverCallback = failoverCallback;
+    }
 }