java状态机框架_一个Java的Actor框架：kilim
除了Akka以外，另外一个将类似Erlang和Scala的Actor的并发模型引入Java的开源框架：kilim/kilim - GitHub，其使用了一种mailbox跨线程共享内存，没有锁或同步。
消息消费者代码如下，监听mailbox：
public class Calculator extends Task{
private Mailbox mailbox;
public Calculator(Mailbox mailbox) {
super();
this.mailbox = mailbox;
}
@[author]Override[/author]
public void execute() throws Pausable, Exception {
while (true) {
Calculation calc = mailbox.get(); // blocksif (calc.getAnswer() == null) {
calc.setAnswer(calc.getDividend().divide(calc.getDivisor(), 8,
RoundingMode.HALF_UP));
System.out.println("Calculator determined answer");
mailbox.putnb(calc);
}
Task.sleep(1000);
}
}
}
消息发生者，向mailbox发送消息：
public class DeferredDivision extends Task {
private Mailbox mailbox;
public DeferredDivision(Mailbox mailbox) {
super();
this.mailbox = mailbox;
}
@[author]Override[/author]
public void execute() throws Pausable, Exception {
Random numberGenerator = new Random(new Date().getTime());
MathContext context = new MathContext(8);
while (true) {
System.out.println("I need to know the answer of something");
mailbox.putnb(new Calculation(
new BigDecimal(numberGenerator.nextDouble(), context),
new BigDecimal(numberGenerator.nextDouble(), context)));
Task.sleep(1000);
Calculation answer = mailbox.getnb();// no blockif (answer != null && answer.getAnswer() != null) {
System.out.println("Answer is: "+ answer.printAnswer());
}
}
}
}
需要使用Ant调用 Kilim's weaver(byte code enhancer)：
客户端测试代码：
Mailbox sharedMailbox = new Mailbox();
Task deferred = new DeferredDivision(sharedMailbox);
Task calculator = new Calculator(sharedMailbox);
deffered.start();
calculator.start();
在"events vs. threads"争论提及两个问题：线程是重量的；其次线程范式隐式的和共享内存锁联系在一起，导致性能陷阱；而Kilim 试图证明线程也可以和状态机一样轻量，甚至提供一个自动的线程stack管理特性(也就没有必要的 "return to the mainloop" 返回主循环的编程习惯).