feat: 新增并发型状态机(基于CAS实现, 未完成).

2025-02-06 11:11:25 +08:00
parent ad26f59438
commit 52946be558
7 changed files with 171 additions and 0 deletions
--- a/src/main/java/com/serliunx/statemanagement/machine/DefaultConcurrentStateMachine.java
+++ b/src/main/java/com/serliunx/statemanagement/machine/DefaultConcurrentStateMachine.java
@@ -0,0 +1,132 @@
+package com.serliunx.statemanagement.machine;
+
+import com.serliunx.statemanagement.machine.handler.StateHandlerWrapper;
+
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
+
+/**
+ * @author <a href="mailto:serliunx@yeah.net">SerLiunx</a>
+ * @version 1.0.0
+ * @since 2025/2/6
+ */
+public class DefaultConcurrentStateMachine<S> extends AbstractStateMachine<S> implements ConcurrentStateMachine<S> {
+
+    /**
+     * 当前状态
+     */
+    private final AtomicInteger index = new AtomicInteger(0);
+
+    DefaultConcurrentStateMachine(List<S> stateList,
+                                         Map<S, List<StateHandlerWrapper<S>>> entryHandlers,
+                                         Map<S, List<StateHandlerWrapper<S>>> leaveHandlers,
+                                         Map<String, List<StateHandlerWrapper<S>>> exchangeHandlers,
+                                         Map<Object, List<Consumer<StateMachine<S>>>> eventRegistries,
+                                         Executor executor,
+                                         Boolean async) {
+        super(stateList, entryHandlers, leaveHandlers, exchangeHandlers, eventRegistries, executor, async);
+    }
+
+    @Override
+    public boolean compareAndSet(S expectedValue, S newValue) {
+        int current = indexOf(expectedValue);
+        int newIndex = indexOf(newValue);
+        if (current == -1 || newIndex == -1)
+            return false;
+        return index.compareAndSet(current, newIndex);
+    }
+
+    /**
+     * 使用CAS不断尝试将当前状态重置回默认值(0)
+     *
+     * @param invokeHandlers    是否唤醒状态处理器
+     */
+    @Override
+    public void reset(boolean invokeHandlers) {
+        if (isDefault())
+            return;
+        exchangeToTarget(0);
+        // TODO invokeHandlers
+    }
+
+    @Override
+    public boolean switchTo(S state, boolean invokeHandlers) {
+        int i = indexOf(state);
+        if (i == -1 ||
+                i == index.get()) {
+            return false;
+        }
+        exchangeToTarget(i);
+        return true;
+    }
+
+    @Override
+    public S switchPrevAndGet(boolean invokeHandlers) {
+        S oldState = get(index.get());
+
+        S newState = get(index.get());
+        if (invokeHandlers)
+            invokeHandlers(oldState, newState);
+        return newState;
+    }
+
+    @Override
+    public S getAndSwitchPrev(boolean invokeHandlers) {
+        return super.getAndSwitchPrev(invokeHandlers);
+    }
+
+    @Override
+    public void switchPrev(boolean invokeHandlers) {
+        super.switchPrev(invokeHandlers);
+    }
+
+    @Override
+    public S switchNextAndGet(boolean invokeHandlers) {
+        return super.switchNextAndGet(invokeHandlers);
+    }
+
+    @Override
+    public S getAndSwitchNext(boolean invokeHandlers) {
+        return super.getAndSwitchNext(invokeHandlers);
+    }
+
+    @Override
+    public void switchNext(boolean invokeHandlers) {
+        super.switchNext(invokeHandlers);
+    }
+
+    @Override
+    public void publish(Object event) {
+
+    }
+
+    /**
+     * 是否为默认状态
+     */
+    private boolean isDefault() {
+        return index.get() == 0;
+    }
+
+    /**
+     * 移动下标至上一个状态
+     */
+    public void exchangeToPrev() {
+        final int size = size();
+    }
+
+    /**
+     * 切换到指定状态值
+     * <li> 使用CAS一直尝试, 直到成功
+     *
+     * @param target    目标值
+     */
+    private void exchangeToTarget(int target) {
+        int currentValue;
+        do {
+            currentValue = index.get();
+        } while (!index.compareAndSet(currentValue, target));
+    }
+}