我创建了一个Java GUI应用程序，作为许多低级外部进程的包装器。该实用程序可以正常工作，但是急需一项重大改进。
我希望我的外部进程以非阻塞方式运行，这将使我能够并行处理更多请求。简而言之，我想能够在生成数据时处理来自外部进程的数据。但是，似乎我的基本尝试检查外部进程是否仍在运行是阻塞的。
以下是我的ExternalProcess类的摘录。有关线程和阻塞的特定Java功能问题，请参见内联注释。
我希望我的外部进程以非阻塞方式运行，这将使我能够并行处理更多请求。简而言之，我想能够在生成数据时处理来自外部进程的数据。但是，似乎我的基本尝试检查外部进程是否仍在运行是阻塞的。
以下是我的ExternalProcess类的摘录。有关线程和阻塞的特定Java功能问题，请参见内联注释。
public void Execute()
{
System.out.println("Starting thread ...\n");
Runner = new Thread(this, "ExternalProcessTest");
Runner.run();
System.out.println("Ending thread ...\n");
}
public void run()
{
System.out.println("In run method ...\n"); // Debug purposes only.
// Show that we are in the run loop.
try
{
// Execute string command SomeCommand as background process ...
Process = Runtime.getRuntime().exec(SomeCommand);
while(IsRunning())
{
// External process generates file IO. I want to process these
// files inside this loop. For the purpose of this demo I have
// removed all file processing to eliminate it as the cause
// of blocking. THIS ROUTINE STILL BLOCKS!
Thread.sleep(1000);
}
}
catch(Exception e)
{
System.out.println(e);
}
System.out.println("Exiting run method ...\n"); // Debug purposes only.
// Show that we are exiting the run loop.
}
// Process (instantiated from Runtime.getRuntime().execute doesn't supports
// either fire-and-forget backgrounding (non-blocking) or you can wait for
// the process to finish using the waitFor() method (blocking). I want to
// be able to execute a non-blocking external process that I monitor via
// threading allowing me to process the external process file IO as it is
// created. To facilitate this goal, I have created an isRunning() method
// that uses the exitValue() method. If the process is still running, a
// call to exitValue() will throw an IllegalThreadStateException exception.
// So I simply catch this execption to test if the background process is
// finished -- at which point I can stop processing file IO from the
// process. Is this the source of the blocking? If so, is there another
// way to do this?
public boolean IsRunning()
{
boolean isRunning = false;
try
{
int exitVal = Process.exitValue();
}
catch(IllegalThreadStateException e)
{
isRunning = true;
}
return isRunning;
}