com.datastax.driver.core
Enum HostDistance
java.lang.Object
java.lang.Enum<HostDistance>
com.datastax.driver.core.HostDistance
- All Implemented Interfaces:
- Serializable, Comparable<HostDistance>
public enum HostDistance
- extends Enum<HostDistance>
The distance to a Cassandra node as assigned by a
LoadBalancingPolicy
(through its distance
method).
The distance assigned to an host influence how many connections the driver
maintains towards this host. If for a given host the assigned HostDistance
is LOCAL
or REMOTE
, some connections will be maintained by
the driver to this host. More active connections will be kept to
LOCAL
host than to a REMOTE
one (and thus well behaving
LoadBalancingPolicy
should assign a REMOTE
distance only to
hosts that are the less often queried).
However, if an host is assigned the distance IGNORED
, no connection
to that host will maintained active. In other words, IGNORED
should
be assigned to hosts that should not be used by this driver (because they
are in a remote datacenter for instance).
Method Summary |
static HostDistance |
valueOf(String name)
Returns the enum constant of this type with the specified name. |
static HostDistance[] |
values()
Returns an array containing the constants of this enum type, in
the order they are declared. |
LOCAL
public static final HostDistance LOCAL
REMOTE
public static final HostDistance REMOTE
IGNORED
public static final HostDistance IGNORED
values
public static HostDistance[] values()
- Returns an array containing the constants of this enum type, in
the order they are declared. This method may be used to iterate
over the constants as follows:
for (HostDistance c : HostDistance.values())
System.out.println(c);
- Returns:
- an array containing the constants of this enum type, in
the order they are declared
valueOf
public static HostDistance valueOf(String name)
- Returns the enum constant of this type with the specified name.
The string must match exactly an identifier used to declare an
enum constant in this type. (Extraneous whitespace characters are
not permitted.)
- Parameters:
name
- the name of the enum constant to be returned.
- Returns:
- the enum constant with the specified name
- Throws:
IllegalArgumentException
- if this enum type has no constant
with the specified name
NullPointerException
- if the argument is null
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