net.i2p.router.transport.ntcp

Class EventPumper

java.lang.Object

net.i2p.router.transport.ntcp.EventPumper

All Implemented Interfaces:

Runnable

class EventPumper
extends Object
implements Runnable

The main NTCP NIO event loop thread responsible for high-throughput, low-latency handling of inbound and outbound NTCP connections using non-blocking I/O.

This class is optimized for minimal overhead and maximum event dispatch efficiency. All hot paths (e.g., processRead(java.nio.channels.SelectionKey), processWrite(java.nio.channels.SelectionKey), runDelayedEvents()) avoid synchronization, allocations, and unnecessary syscalls.

Key performance characteristics:

• Fixed 200ms selector timeout for consistent latency
• Immediate wakeup() on pending I/O (no cooldown)
• Duplicate-free write request tracking via ConcurrentHashSet
• Failsafe iteration every 2 seconds to clean stale connections
• Efficient buffer pooling with bounded size

Constructor Summary

Constructors

Constructor and Description
EventPumper(RouterContext ctx, NTCPTransport transport)

Method Summary

Modifier and Type	Method and Description
static ByteBuffer	acquireBuf() High-frequency path in thread.
void	blockIP(byte[] ip)
static void	clearInterest(SelectionKey key, int op)
long	getIdleTimeout()
boolean	isAlive() Selector can take quite a while to close after calling stopPumping()
boolean	processWrite(NTCPConnection con, SelectionKey key)
void	register(ServerSocketChannel chan) Register the acceptor.
void	registerConnect(NTCPConnection con) Outbound connection registration with optional retry backoff.
static void	releaseBuf(ByteBuffer buf) Return a read buffer to the pool.
void	run()
static void	setInterest(SelectionKey key, int op)
void	startPumping()
void	stopPumping()
void	wantsRead(NTCPConnection con) This is only called from NTCPConnection.complete() if there is more data, which is rare (never?) so we don't need to check for dups or make _wantsRead a Set.
void	wantsWrite(NTCPConnection con) Called by the connection when it has data ready to write (after bw allocation).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EventPumper

public EventPumper(RouterContext ctx,
                   NTCPTransport transport)

Method Detail

acquireBuf

public static ByteBuffer acquireBuf()

High-frequency path in thread.

blockIP

public void blockIP(byte[] ip)

clearInterest

public static void clearInterest(SelectionKey key,
                                 int op)
                          throws CancelledKeyException

Throws:

CancelledKeyException

getIdleTimeout

public long getIdleTimeout()

isAlive

public boolean isAlive()

Selector can take quite a while to close after calling stopPumping()

processWrite

public boolean processWrite(NTCPConnection con,
                            SelectionKey key)

register

public void register(ServerSocketChannel chan)

Register the acceptor. This is only called from NTCPTransport.bindAddress(), so it isn't clear why this needs a queue.

registerConnect

public void registerConnect(NTCPConnection con)

Outbound connection registration with optional retry backoff.

releaseBuf

public static void releaseBuf(ByteBuffer buf)

Return a read buffer to the pool. These buffers must be from acquireBuf(), i.e. capacity() == BUF_SIZE. High-frequency path in thread.

run

public void run()

Specified by:

run in interface Runnable

setInterest

public static void setInterest(SelectionKey key,
                               int op)
                        throws CancelledKeyException

Throws:

CancelledKeyException

startPumping

public void startPumping()

stopPumping

public void stopPumping()

wantsRead

public void wantsRead(NTCPConnection con)

This is only called from NTCPConnection.complete() if there is more data, which is rare (never?) so we don't need to check for dups or make _wantsRead a Set.

wantsWrite

public void wantsWrite(NTCPConnection con)

Called by the connection when it has data ready to write (after bw allocation). Only wakeup if new.