在《JXTA JavaTM Standard Edition v2.5: Programmers Guide》的第17页中,介绍了JxtaSocket和JxtaBiDiPipe;根据该介绍,这两种通信机制都提供双向可靠的通信信道。
但有时可能处于性能的考虑,我们希望使用类似UDP那种方式,而又不想使用低级管道(需要手工实现双向通信):
这时可以仍然使用JxtaBiDiPipe,并调用其setReliable(false),将其 可靠性参数设置为false。
一个使用场景就是通过RTP协议传输音频/视频(在自定义的传输层使用JXSE)。
RTP协议本身是不可靠的,那么如果将RTP建立在可靠性协议(例如TCP)之上,会不会对性能有影响?
不知到上面的分析是否正确?
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查看JxtaBiDiPipe的源代码,将isReliable标志设置为true,确实多做了额外的工作
/**
* If {@code true} then we are using the underlying end-to-end ACK reliable
* layer to ensure that messages are received by the remote peer.
*/
protected volatile boolean isReliable = false;
protected volatile ReliableInputStream ris = null;
protected volatile ReliableOutputStream ros = null;
/**
* creates all the reliability objects
*/
private void createRLib() {
if (isReliable) {
if (outgoing == null) {
outgoing = new OutgoingMsgrAdaptor(msgr, retryTimeout);
}
if (ros == null) {
ros = new ReliableOutputStream(group, outgoing, new FixedFlowControl(windowSize), group.getTaskManager().getScheduledExecutorService());
}
if (ris == null) {
ris = new ReliableInputStream(group, outgoing, retryTimeout, this);
}
}
}
* If {@code true} then we are using the underlying end-to-end ACK reliable
* layer to ensure that messages are received by the remote peer.
*/
protected volatile boolean isReliable = false;
protected volatile ReliableInputStream ris = null;
protected volatile ReliableOutputStream ros = null;
/**
* creates all the reliability objects
*/
private void createRLib() {
if (isReliable) {
if (outgoing == null) {
outgoing = new OutgoingMsgrAdaptor(msgr, retryTimeout);
}
if (ros == null) {
ros = new ReliableOutputStream(group, outgoing, new FixedFlowControl(windowSize), group.getTaskManager().getScheduledExecutorService());
}
if (ris == null) {
ris = new ReliableInputStream(group, outgoing, retryTimeout, this);
}
}
}
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