org.ka2ddo.yaac.util

Class ServiceDiscovery

java.lang.Object

org.ka2ddo.yaac.util.ServiceDiscovery

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public abstract class ServiceDiscovery
extends java.lang.Object
implements java.io.Closeable

This class handles requests for Service Discovery lookups via RFC 6763, using any of several means:

1. if on a system with an avahi daemon, use the daemon as a proxy for the request.
2. if avahi can't be found, try to open a dnsjava Resolver socket on the Multicast DNS (RFC 6762) port and do the query directly.
3. fail if neither scheme can be used.

Author:

Andrew Pavlin, KA2DDO

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ServiceDiscovery.Protocol Protocol being reported for a particular service.
static class	ServiceDiscovery.SDAnswer Structure containing one (of possibly several) successful answers for looking up a service by Service Discovery.
static interface	ServiceDiscovery.SDCallback Interface for incrementally receiving the results of a service lookup request.
static interface	ServiceDiscovery.SDListener Interface for receiving possibly asynchronous complete answer for a service lookup request.

Method Summary

Modifier and Type	Method and Description
abstract void	browse(java.lang.String serviceType, ServiceDiscovery.SDCallback callback) Request a service lookup for the desired service category.
static ServiceDiscovery.SDAnswer[]	browseService(java.lang.String service) Do a Service Discovery browse and synchronously report the results.
static void	browseService(java.lang.String service, ServiceDiscovery.SDListener listener) Do a Service Discovery browse and potentially asynchronously report the results.
abstract void	close() Close down an open ServiceDiscovery handler and release any resources it is holding.
static ServiceDiscovery	getSDClient() Get an instance of a ServiceDiscovery client that will work on the local system, for possible multiple lookups.
abstract void	lookup(java.lang.String serviceType, ServiceDiscovery.SDCallback callback) Request a service lookup for the desired single service instance.
static ServiceDiscovery.SDAnswer[]	lookupService(java.lang.String service) Do a Service Discovery lookup and synchronously report the results.
static void	lookupService(java.lang.String service, ServiceDiscovery.SDListener listener) Do a Service Discovery lookup and potentially asynchronously report the results.

Methods inherited from class java.lang.Object

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

Method Detail

browse

public abstract void browse(java.lang.String serviceType,
                            ServiceDiscovery.SDCallback callback)

Request a service lookup for the desired service category.

Parameters:

serviceType - String name of service, such as "_http._tcp"

callback - SDCallback to receive the information as it is received

lookup

public abstract void lookup(java.lang.String serviceType,
                            ServiceDiscovery.SDCallback callback)

Request a service lookup for the desired single service instance.

Parameters:

serviceType - String name of service instance, such as "fred._http._tcp"

callback - SDCallback to receive the information as it is received

close

public abstract void close()
                    throws java.io.IOException

Close down an open ServiceDiscovery handler and release any resources it is holding.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException - if close failed for some reason

browseService

public static void browseService(java.lang.String service,
                                 ServiceDiscovery.SDListener listener)

Do a Service Discovery browse and potentially asynchronously report the results. This method may or may not return before one of the methods on SDListener is called to report the results.

Parameters:

service - String name of service to look up, such as "_http._tcp"

listener - SDListener that will receive the results

browseService

public static ServiceDiscovery.SDAnswer[] browseService(java.lang.String service)

Do a Service Discovery browse and synchronously report the results.

Parameters:

service - String name of service to look up, such as "_http._tcp"

Returns:

array of SDAnswer structures with the found service instances, or null if the browse failed with some sort of error

lookupService

public static void lookupService(java.lang.String service,
                                 ServiceDiscovery.SDListener listener)

Do a Service Discovery lookup and potentially asynchronously report the results. This method may or may not return before one of the methods on SDListener is called to report the results.

Parameters:

service - String name of service to look up, such as "_http._tcp"

listener - SDListener that will receive the results

lookupService

public static ServiceDiscovery.SDAnswer[] lookupService(java.lang.String service)

Do a Service Discovery lookup and synchronously report the results.

Parameters:

service - String name of service to look up, such as "_http._tcp"

Returns:

array of SDAnswer structures with the found service instances, or null if the lookup failed with some sort of error

getSDClient

public static ServiceDiscovery getSDClient()
                                    throws java.net.UnknownServiceException

Get an instance of a ServiceDiscovery client that will work on the local system, for possible multiple lookups.

Returns:

instance of ServiceDiscovery that can make queries on the local operating system

Throws:

java.net.UnknownServiceException - if there is no known way to make ServiceDiscovery queries from Java code on this system