org.ldaptive

Class DnsSrvConnectionStrategy

java.lang.Object

org.ldaptive.DnsSrvConnectionStrategy

All Implemented Interfaces:

ConnectionStrategy

public class DnsSrvConnectionStrategy
extends Object
implements ConnectionStrategy

DNS SRV connection strategy. Queries a DNS server for SRV records and uses those records to construct a list of URLs. A time to live can be set to control how often the DNS server is consulted. See http://www.ietf.org/rfc/rfc2782.txt.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	DnsSrvConnectionStrategy.SrvRecord SRV record.

Field Summary

Fields

Modifier and Type	Field and Description
private static long	DEFAULT_TTL Default time to live for DNS results.
private static String	DNS_CONTEXT_FACTORY JNDI context factory for DNS.
private static String	DNS_PROVIDER_URL JNDI context factory for DNS.
private Map<String,Object>	jndiEnv JNDI environment.
protected Logger	logger Logger for this class.
private List<DnsSrvConnectionStrategy.SrvRecord>	srvRecords SRV records from the last DNS lookup.
private long	srvTtl Time to live for SRV records in milliseconds.

Constructor Summary

Constructors

Constructor and Description
DnsSrvConnectionStrategy() Creates a new DNS SRV connection strategy.
DnsSrvConnectionStrategy(long ttl) Creates a new DNS SRV connection strategy.
DnsSrvConnectionStrategy(Map<String,Object> env, long ttl) Creates a new DNS SRV connection strategy.

Method Summary

Modifier and Type	Method and Description
Map<String,Object>	getJndiEnvironment() Returns the JNDI environment used for DNS lookup.
String[]	getLdapUrls(ConnectionFactoryMetadata metadata) Returns a list of URLs retrieved from DNS SRV records.
long	getTimeToLive() Returns the time that DNS lookups will be cached.
protected List<DnsSrvConnectionStrategy.SrvRecord>	retrieveDNSRecords(String name, Map<String,Object> props, long ttl) Uses JNDI to retrieve the DNS SRV record from the supplied url.
void	setJndiEnvironment(Map<String,Object> env) Sets the JNDI environment used for DNS lookups.
void	setTimeToLive(long ttl) Sets the time that DNS lookups will be cached.
protected List<DnsSrvConnectionStrategy.SrvRecord>	sortSrvRecords(List<DnsSrvConnectionStrategy.SrvRecord> records) Sorts the supplied SRV records according to RFC 2782.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

DNS_CONTEXT_FACTORY

private static final String DNS_CONTEXT_FACTORY

JNDI context factory for DNS.

See Also:

Constant Field Values

DNS_PROVIDER_URL

private static final String DNS_PROVIDER_URL

JNDI context factory for DNS.

See Also:

Constant Field Values

DEFAULT_TTL

private static final long DEFAULT_TTL

Default time to live for DNS results. Value is 3600000L.

See Also:

Constant Field Values

logger

protected final Logger logger

Logger for this class.

jndiEnv

private Map<String,Object> jndiEnv

JNDI environment.

srvTtl

private long srvTtl

Time to live for SRV records in milliseconds.

srvRecords

private List<DnsSrvConnectionStrategy.SrvRecord> srvRecords

SRV records from the last DNS lookup.

Constructor Detail

DnsSrvConnectionStrategy

public DnsSrvConnectionStrategy()

Creates a new DNS SRV connection strategy.

DnsSrvConnectionStrategy

public DnsSrvConnectionStrategy(long ttl)

Creates a new DNS SRV connection strategy.

Parameters:

ttl - time to live in milliseconds for SRV records

DnsSrvConnectionStrategy

public DnsSrvConnectionStrategy(Map<String,Object> env,
                                long ttl)

Creates a new DNS SRV connection strategy.

Parameters:

env - JNDI environment

ttl - time to live in milliseconds for SRV records

Method Detail

getJndiEnvironment

public Map<String,Object> getJndiEnvironment()

Returns the JNDI environment used for DNS lookup.

Returns:

jndi environment

getTimeToLive

public long getTimeToLive()

Returns the time that DNS lookups will be cached.

Returns:

time to live in milliseconds

setJndiEnvironment

public void setJndiEnvironment(Map<String,Object> env)

Sets the JNDI environment used for DNS lookups. If no Context.INITIAL_CONTEXT_FACTORY is set, it is defaulted to DNS_CONTEXT_FACTORY. If no Context.PROVIDER_URL is set, it is defaulted to DNS_PROVIDER_URL.

Parameters:

env - jndi environment or null

setTimeToLive

public void setTimeToLive(long ttl)

Sets the time that DNS lookups will be cached.

Parameters:

ttl - time to live in milliseconds

getLdapUrls

public String[] getLdapUrls(ConnectionFactoryMetadata metadata)

Returns a list of URLs retrieved from DNS SRV records. The LDAP URL in the supplied metadata can be a space delimited list of DNS servers, each will be tried in order.

Specified by:

getLdapUrls in interface ConnectionStrategy

Parameters:

metadata - which can be used to produce the URL list

Returns:

list of URLs to attempt connections to

retrieveDNSRecords

protected List<DnsSrvConnectionStrategy.SrvRecord> retrieveDNSRecords(String name,
                                                                      Map<String,Object> props,
                                                                      long ttl)
                                                               throws NamingException

Uses JNDI to retrieve the DNS SRV record from the supplied url. The supplied properties are passed into the JNDI context.

Parameters:

name - of the SRV records

props - for the JNDI context

ttl - time to live for each SRV record

Returns:

list of LDAP URLs

Throws:

NamingException - if the DNS record cannot be retrieved

sortSrvRecords

protected List<DnsSrvConnectionStrategy.SrvRecord> sortSrvRecords(List<DnsSrvConnectionStrategy.SrvRecord> records)

Sorts the supplied SRV records according to RFC 2782. Records with the lowest priority are first. Records with the same priority are arranged by weight with higher weights having a greater chance to be ordered first.

Parameters:

records - to sort

Returns:

sorted records

toString

public String toString()

Overrides:

toString in class Object