生命周期组件框架：生命周期描述语言——并发加写锁和解写锁执行过程示例
@StateMachine static interface LockingStateMachine { @StateSet static interface States { @Initial @Function(transition = LockingStateMachine.Transitions.Start.class, value = Started.class) static interface Created {} @Functions({ @Function(transition = LockingStateMachine.Transitions.Stop.class, value = Stopped.class), @Function(transition = LockingStateMachine.Transitions.Cancel.class, value = Canceled.class) }) static interface Started {} @End static interface Stopped {} @End static interface Canceled {} } @TransitionSet static interface Transitions { static interface Start {} static interface Stop {} static interface Cancel {} } } static interface ILockingReactiveObject { public abstract int getCounter(); public abstract void start(); public abstract void stop(); public abstract void cancel(); }?
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public static class SimpleLock implements LifecycleLockStrategry { private static Logger logger = Logger.getLogger("Lifecycle Framework"); private static volatile int depth = 0; private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(); @Override public void lockRead(Object reactiveObject) { logLockingMethod(reactiveObject, "lockRead: "); lock.readLock().lock(); depth++; } private void logLockingMethod(Object reactiveObject, String methodName) { final StringBuilder builder = getIndent(); builder.append(methodName + reactiveObject); logger.fine(builder.toString()); } private StringBuilder getIndent() { StringBuilder builder = new StringBuilder(); for ( int i = 0; i klass) throws Throwable { final ExecutorService executorService = Executors.newFixedThreadPool(7); for ( int i = 0; i c1 = new Callable() { @Override public LifecycleException call() throws Exception { try { object.stop(); return null; } catch (LifecycleException e) { return e; } } }; Callable c2 = new Callable() { @Override public LifecycleException call() throws Exception { try { object.cancel(); return null; } catch (LifecycleException e) { return e; } } }; if ( i % 2 == 0 ) { Callable temp = c1; c1 = c2; c2 = temp; } final Future f1 = executorService.submit(c1); final Future f2 = executorService.submit(c2); final Callable c3 = new Callable() { @Override public Exception call() throws Exception { try { final LifecycleException e1 = f1.get(); final LifecycleException e2 = f2.get(); assertFalse(( null != e1 && null != e2 ) || ( null == e1 && null == e2 )); final LifecycleException e = null != e1 ? e1 : e2; System.out.println(e.toString()); assertEquals(LifecycleCommonErrors.ILLEGAL_TRANSITION_ON_STATE, e.getErrorCode()); assertEquals(2, object.getCounter()); return null; } catch (Exception e) { return e; } } }; final Future f3 = executorService.submit(c3); if ( null != f3.get() ) { fail(f3.get().getMessage()); } } }?
日志截屏如下（请点击放大）
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日志解释：
执行过程中的加（获取）写锁和解（释放）写锁的过程
[FINE]: Found Intercept Point: class net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject.start( )
[FINE]: Intercepting....instatiating InterceptContext ...
[FINE]: Intercepting....InterceptorController is doing exec ...
[FINE]: Intercepting....instantiating LifecycleInterceptor
[FINE]: intercepting with :net.madz.bcel.intercept.LifecycleInterceptor @preExec
[FINE]: lockWrite: net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@62b9f149
[FINE]: intercepting [net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@62b9f149]
from state: [Created]
[FINE]: Step 1. start validating State [Created]
[FINE]: Step 2. start validating transition: [Start] on state: [Created]
[FINE]: Step 3. start validating inbound relation constraint is next state is predictable before method invocation.
[FINE]: Step 4. start callback before state change from : Created => to : Started
[FINE]: intercepting with: net.madz.bcel.intercept.CallableInterceptor @intercept
[FINE]: intercepting with :net.madz.bcel.intercept.LifecycleInterceptor @postExec
[FINE]: Step 5. start validating inbound relation constraint is next state after method invocation.
[FINE]: Step 6. Set next state to reactiveObject.
[FINE]: Step 6. ReactiveObject is tranisited to state: [Started]
[FINE]: Step 7. Start Callback after state change from : Created => to : Started
[FINE]: unlockWrite: net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@62b9f149
[FINE]: Step 8. Start fire state change event.
[FINE]: intercepting with :net.madz.bcel.intercept.LifecycleInterceptor @cleanup
[FINE]: Intercepting....LifecycleInterceptor is doing cleanup ...
并发执行同步过程日志
//线程一开始获取写锁
[FINE]: lockWrite: net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39
//线程二开始获取写锁
[FINE]: lockWrite: net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39
//线程一得到写锁并继续执行生命周期引擎
[FINE]: intercepting? [net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39]
from state: [Started]
[FINE]: Step 1. start validating State [Started]
[FINE]: Step 2. start validating transition: [Stop] on state: [Started]
[FINE]: Step 3. start validating inbound relation constraint is next state is predictable before method invocation.
[FINE]: Step 4. start callback before state change from : Started => to : Stopped
[FINE]: intercepting with: net.madz.bcel.intercept.CallableInterceptor @intercept
[FINE]: intercepting with :net.madz.bcel.intercept.LifecycleInterceptor @postExec
[FINE]: Step 5. start validating inbound relation constraint is next state after method invocation.
[FINE]: Step 6. Set next state to reactiveObject.
[FINE]: Step 6. ReactiveObject is tranisited to state: [Stopped]
[FINE]: Step 7. Start Callback after state change from : Started => to : Stopped
//第一线程执行完Transition开始解写锁
[FINE]: unlockWrite: net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39
[FINE]: Step 8. Start fire state change event.
//线程二得到写锁开始执行引擎
[FINE]: intercepting? [net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39]
from state: [Stopped] //此时状态已经变为Stopped,线程一导致的变化至此已被线程二看见
[FINE]: intercepting with :net.madz.bcel.intercept.LifecycleInterceptor @cleanup
[FINE]: Step 1. start validating State [Stopped]
[FINE]: Intercepting....LifecycleInterceptor is doing cleanup ...
[FINE]: Step 2. start validating transition: [Cancel] on state: [Stopped]
[FINE]: intercepting with :net.madz.bcel.intercept.LifecycleInterceptor @cleanup
[FINE]: Intercepting....LifecycleInterceptor is doing cleanup ...
[SEVERE]: ReactiveObject: [net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39] was failed to transit from state: [Stopped] to state: [(Had Not Been Evaluated)] with following error:
//由于在执行过程中另一线程导致状态发生变化，而使得本线程的Transition不合法
[SEVERE]: Illegal Request Found on object net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39: Transition Cancel is not allowed while object is on Stopped state.?
//线程二Transition失败后开始释放写[FINE]: unlockWrite: net.madz.lifecycle.engine.LifecycleLockTestMetadata$SimpleLockingReactiveObject@31c1fb39
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