com.sleepycat.je.rep.utilint

Class FreePortLocator

java.lang.Object

com.sleepycat.je.rep.utilint.FreePortLocator

public class FreePortLocator
extends Object

An iterator to iterate over the free ports on an interface.

Constructor Summary

Constructors

Constructor and Description
FreePortLocator(String hostname, int portStart, int portEnd) Constructor identifying the interface and the port range within which to look for free ports.

Method Summary

Modifier and Type	Method and Description
int	getPortEnd()
int	getPortStart()
int	next() Returns the next free port.
void	skip(int num) Skip a number of ports.

Methods inherited from class java.lang.Object

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

Constructor Detail

FreePortLocator

public FreePortLocator(String hostname,
                       int portStart,
                       int portEnd)

Constructor identifying the interface and the port range within which to look for free ports. The port range specified by the arguments must be < 32768, that is, it should be outside the dynamic port range that is typically configured on most machines.

See Also:

Anonymous ports for details regarding port configuration for tests.

Method Detail

getPortStart

public int getPortStart()

getPortEnd

public int getPortEnd()

next

public int next()

Returns the next free port. Note that it's possible that on a busy machine another process may grab the "free" port before it's actually used. There is somewhat AIsh aspect to the code below. In general it tries to be very conservative, using different techniques so that it works reasonably well on Linux, Mac OS and Windows. Note: The use of setReuseAddress after a bind operation may look dubious, since it runs counter to the API doc, but it helps based on actual tests. It's also the idiom used by Apache Camel to find a free port. It, at least, can't hurt.

skip

public void skip(int num)

Skip a number of ports.