change: 代码整理、定向切换时校验当前状态.

src/main/java/com/serliunx/statemanagement/machine/StandardStateMachine.java

@@ -149,8 +149,16 @@ public class StandardStateMachine<S> extends AbstractStateManager<S> implements
 
 	@Override
 	public boolean switchTo(S state) {
+		int i = indexOf(state);
+		if (i == -1 || i == currentIndex()) {
+			return false;
+		}
 		try {
 			writeLock.lock();
+			// 重新检查
+			if (i == currentIndex()) {
+				return false;
+			}
 			S oldState = get();
 			boolean result = super.switchTo(state);
 			if (result) {

src/main/java/com/serliunx/statemanagement/machine/StateMachine.java

@@ -11,7 +11,7 @@ import com.serliunx.statemanagement.manager.BidirectionalStateManager;
  * <li> 切出指定状态时触发	(离开事件)
  * <li> 从A切换到B状态时触发	(交换事件)
  * <p>
- * 推荐使用{@link StateMachineBuilder} 来构建状态机.
+ * 请使用{@link StateMachineBuilder} 来构建状态机.
  *
  * @author <a href="mailto:serliunx@yeah.net">SerLiunx</a>
  * @version 1.0.0
@@ -22,5 +22,12 @@ import com.serliunx.statemanagement.manager.BidirectionalStateManager;
  */
 public interface StateMachine<S> extends BidirectionalStateManager<S> {
 
-
+    /**
+     * 切换到指定状态
+     * <li> 在使用状态机的情况, 仅切换成功才会触发注册的各种事件.
+     *
+     * @param state 新的状态
+     * @return 切换成功返回真, 否则返回假
+     */
+    boolean switchTo(S state);
 }

src/main/java/com/serliunx/statemanagement/machine/StateMachineBuilder.java

@@ -2,7 +2,6 @@ package com.serliunx.statemanagement.machine;
 
 import com.serliunx.statemanagement.machine.handler.StateHandler;
 import com.serliunx.statemanagement.machine.handler.StateHandlerWrapper;
-import com.serliunx.statemanagement.manager.BidirectionalStateManager;
 
 import java.util.*;
 import java.util.concurrent.Executor;

src/main/java/com/serliunx/statemanagement/machine/handler/StateHandlerProcessParams.java

@@ -1,7 +1,5 @@
 package com.serliunx.statemanagement.machine.handler;
 
-import com.serliunx.statemanagement.manager.BidirectionalStateManager;
-
 /**
  * 状态处理器入参
  * <p>

src/main/java/com/serliunx/statemanagement/manager/AbstractStateManager.java

@@ -74,11 +74,15 @@ public abstract class AbstractStateManager<S> implements StateManager<S> {
 	@Override
 	public boolean switchTo(S state) {
 		int i = indexOf(state);
-		if (i == -1) {
+		if (i == -1 || i == index) {
 			return false;
 		}
 		try {
 			writeLock.lock();
+			// 重新检查
+			if (i == index) {
+				return false;
+			}
 			index = i;
 		} finally {
 			writeLock.unlock();

src/main/java/com/serliunx/statemanagement/manager/DefaultUnidirectionalStateManager.java

@@ -61,11 +61,18 @@ public class DefaultUnidirectionalStateManager<S> extends AbstractStateManager<S
 
 	@Override
 	public boolean switchTo(S state) {
-		try {
-			writeLock.lock();
 		final int i;
 		if ((i = indexOf(state)) == -1 ||
-					(!isLast() && i < currentIndex()) ||
+				i == currentIndex()) {
+			return false;
+		}
+		try {
+			writeLock.lock();
+			// 重新检查
+			if (i == currentIndex()) {
+				return false;
+			}
+			if ((!isLast() && i < currentIndex()) ||
 					(isLast() && i != getDefault())) {
 				return false;
 			}

src/main/java/com/serliunx/statemanagement/manager/StateManager.java

@@ -1,7 +1,5 @@
 package com.serliunx.statemanagement.manager;
 
-import java.util.concurrent.locks.ReentrantReadWriteLock;
-
 /**
  * 状态管理器
  * <p>

src/test/java/com/serliunx/statemanagement/MachineTest.java

@@ -22,20 +22,23 @@ public class MachineTest {
 	public void testStandardStateMachine() {
 		StateMachine<PrinterState> stateMachine = StateMachineBuilder.from(PrinterState.class)
 				.async(false)
+				.states(PrinterState.values())
+				.executor(Executors.newFixedThreadPool(16))
 				.whenLeave(PrinterState.PRINTING, h -> {
 					System.out.println(Thread.currentThread().getName() + ": leave PRINTING");
 				})
-				.states(PrinterState.values())
-				.executor(Executors.newFixedThreadPool(16))
 				.whenEntry(PrinterState.SCANNING, h -> {
 					System.out.println(Thread.currentThread().getName() + ": " + h.getFrom() + " >>> " + h.getTo());
-				}, false)
+				})
 				.whenEntry(PrinterState.PRINTING, h -> {
 					System.out.println(Thread.currentThread().getName() + ": " + h.getFrom() + " >>> " + h.getTo());
-				}, false, Executors.newFixedThreadPool(1))
+				})
 				.exchange(PrinterState.STOPPED, PrinterState.IDLE, h -> {
 					System.out.println(Thread.currentThread().getName() + ": " + h.getFrom() + " >>> " + h.getTo());
 				})
 				.build();
+
+		stateMachine.switchTo(PrinterState.PRINTING);
+		stateMachine.switchNext();
 	}
 }

src/test/java/com/serliunx/statemanagement/ManagerTest.java

@@ -1,5 +1,8 @@
 package com.serliunx.statemanagement;
 
+import com.serliunx.statemanagement.manager.DefaultUnidirectionalStateManager;
+import com.serliunx.statemanagement.manager.UnidirectionalStateManager;
+import com.serliunx.statemanagement.support.PrinterState;
 import lombok.extern.slf4j.Slf4j;
 import org.junit.Test;
 
@@ -15,6 +18,10 @@ public class ManagerTest {
 
 	@Test
 	public void testUnidirectionalStateManager() {
+		UnidirectionalStateManager<PrinterState> unidirectionalStateManager =
+				new DefaultUnidirectionalStateManager<>(PrinterState.values());
 
+		System.out.println(unidirectionalStateManager.switchTo(PrinterState.IDLE));
+		System.out.println(unidirectionalStateManager.switchTo(PrinterState.SCANNING));
 	}
 }