检查 OutputStream 的管道是否损坏

Question

void sendMessage(String message, OutputStream os) {
    try {
        ExternalLibrary.sendMessage(message, os);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

I have the above bit of code that uses an external method to send a message through an output stream. If there's an IO exception (eg a broken pipe), that method will perform some logging and throw than IOException. I want to prevent the logging from happening if there's a broken pipe. The logging performed by the method is vague and difficult to look through, so I only want to call it if I can be reasonably sure the pipe isn't broken. Something like:

void sendMessage(String message, OutputStream os) {
    if (!os.isClosed()) {
        try {
            ExternalLibrary.sendMessage(message, os);
        } catch (IOException e) {
            e.printStackTrace();
        }
    } else {
        logger.error("Broken pipe");
    }
}

Answer 1

Since you are in a MultiThreaded environment you can never be sure if a asynchrouius task invalidate the OutputStream throu a different Thread.

A simplified example:

You start the sending of the message. Right after sending the message your PC is running out of RAM, the OutputStream breaks because it can not allocate more RAM - voila your stream is broken. This is happening after the calling of the function but before the leave of the function.

Answer 2

The concept of "broken" is unknown to a OutputStream! Also a Pipe is a different kind of design. You mean Streams.

Only the method write(*) is able to produce a IOException what can be used to express a broken pipe.

Unfortunately the method write(*) is called inside ExternalLibrary.sendMessage(message, os); .

That is too late for your task to

call it if I can be reasonably sure the pipe isn't broken