Host (DataStax Enterprise Java Driver - Binary distribution 1.4.2 API)

java.lang.Object
- com.datastax.driver.core.Host

```
public class Host
extends Object
```
A Cassandra node.
This class keeps the information the driver maintain on a given Cassandra node.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static interface`	`Host.LifecycleAwareStateListener` A `StateListener` that tracks when it gets registered or unregistered with a cluster.
`static interface`	`Host.StateListener` Interface for listeners that are interested in hosts added, up, down and removed events.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`boolean`	`equals(Object other)`
`InetAddress`	`getAddress()` Returns the address that the driver will use to connect to the node.
`InetAddress`	`getBroadcastAddress()` Returns the node broadcast address (that is, the IP by which it should be contacted by other peers in the cluster), if known.
`VersionNumber`	`getCassandraVersion()` The Cassandra version the host is running.
`String`	`getDatacenter()` Returns the name of the datacenter this host is part of.
`VersionNumber`	`getDseVersion()` The DSE version the host is running.
`String`	`getDseWorkload()` Deprecated. This method returns only the first workload reported by the host; use `getDseWorkloads()` instead.
`Set<String>`	`getDseWorkloads()` The DSE Workloads the host is running.
`UUID`	`getHostId()` Return the host id value for the host.
`InetAddress`	`getListenAddress()` Returns the node listen address (that is, the IP the node uses to contact other peers in the cluster), if known.
`String`	`getRack()` Returns the name of the rack this host is part of.
`ListenableFuture<?>`	`getReconnectionAttemptFuture()` Returns a `ListenableFuture` representing the completion of the reconnection attempts scheduled after a host is marked `DOWN`.
`UUID`	`getSchemaVersion()` Return the current schema version for the host.
`InetSocketAddress`	`getSocketAddress()` Returns the address and port that the driver will use to connect to the node.
`String`	`getState()` Returns a description of the host's state, as seen by the driver.
`Set<Token>`	`getTokens()` Returns the tokens that this host owns.
`int`	`hashCode()`
`boolean`	`isDseGraphEnabled()` Deprecated. As of DSE 5.1, users should determine whether this host has the graph workload enabled by inspecting the contents of `getDseWorkloads()` instead. Note that this method will throw `UnsupportedOperationException` if the system tables do not contain a "graph" column.
`boolean`	`isUp()` Returns whether the host is considered up by the driver.
`String`	`toString()`
`void`	`tryReconnectOnce()` Triggers an asynchronous reconnection attempt to this host.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Method Detail
  - getAddress
```
public InetAddress getAddress()
```
    Returns the address that the driver will use to connect to the node.
    This is a shortcut for getSocketAddress().getAddress().
    
    Returns:
    
    the address.
    
    See Also:
    
    getSocketAddress()
  - getSocketAddress
```
public InetSocketAddress getSocketAddress()
```
    Returns the address and port that the driver will use to connect to the node.
    This is the node's broadcast RPC address, possibly translated if an AddressTranslator has been configured for this cluster.
    The broadcast RPC address is inferred from the following cassandra.yaml file settings:
    1. rpc_address, rpc_interface or broadcast_rpc_address
    2. native_transport_port
    Returns:
    
    the address and port.
    
    See Also:
    
    The cassandra.yaml configuration file
  - getBroadcastAddress
```
public InetAddress getBroadcastAddress()
```
    Returns the node broadcast address (that is, the IP by which it should be contacted by other peers in the cluster), if known.
    This corresponds to the broadcast_address cassandra.yaml file setting and is by default the same as getListenAddress(), unless specified otherwise in cassandra.yaml. This is NOT the address clients should use to contact this node.
    This information is always available for peer hosts. For the control host, it's only available if CASSANDRA-9436 is fixed on the server side (Cassandra versions >= 2.0.16, 2.1.6, 2.2.0 rc1). For older versions, note that if the driver loses the control connection and reconnects to a different control host, the old control host becomes a peer, and therefore its broadcast address is updated.
    
    Returns:
    
    the node broadcast address, if known. Otherwise null.
    
    See Also:
    
    The cassandra.yaml configuration file
  - getListenAddress
```
public InetAddress getListenAddress()
```
    Returns the node listen address (that is, the IP the node uses to contact other peers in the cluster), if known.
    This corresponds to the listen_address cassandra.yaml file setting. This is NOT the address clients should use to contact this node.
    This information is available for the control host if CASSANDRA-9603 is fixed on the server side (Cassandra versions >= 2.0.17, 2.1.8, 2.2.0 rc2). It's currently not available for peer hosts. Note that the current driver code already tries to read a listen_address column in system.peers; when a future Cassandra version adds it, it will be picked by the driver without any further change needed.
    
    Returns:
    
    the node listen address, if known. Otherwise null.
    
    See Also:
    
    The cassandra.yaml configuration file
  - getDatacenter
```
public String getDatacenter()
```
    Returns the name of the datacenter this host is part of.
    The returned datacenter name is the one as known by Cassandra. It is also possible for this information to be unavailable. In that case this method returns null, and the caller should always be aware of this possibility.
    
    Returns:
    
    the Cassandra datacenter name or null if datacenter is unavailable.
  - getRack
```
public String getRack()
```
    Returns the name of the rack this host is part of.
    The returned rack name is the one as known by Cassandra. It is also possible for this information to be unavailable. In that case this method returns null, and the caller should always be aware of this possibility.
    
    Returns:
    
    the Cassandra rack name or null if the rack is unavailable
  - getCassandraVersion
```
public VersionNumber getCassandraVersion()
```
    The Cassandra version the host is running.
    It is also possible for this information to be unavailable. In that case this method returns null, and the caller should always be aware of this possibility.
    
    Returns:
    
    the Cassandra version the host is running.
  - getDseVersion
```
public VersionNumber getDseVersion()
```
    The DSE version the host is running.
    It is also possible for this information to be unavailable. In that case this method returns null, and the caller should always be aware of this possibility.
    
    Returns:
    
    the DSE version the host is running.
  - getDseWorkload
```
@Deprecated
public String getDseWorkload()
```
    Deprecated. This method returns only the first workload reported by the host; use getDseWorkloads() instead.
    
    The main DSE Workload the host is running.
    It is also possible for this information to be unavailable. In that case this method returns null, and the caller should always be aware of this possibility.
    
    Returns:
    
    the DSE workload the host is running.
  - getDseWorkloads
```
public Set<String> getDseWorkloads()
```
    The DSE Workloads the host is running.
    This is based on the "workload" or "workloads" columns in system.local and system.peers.
    Workload labels may vary depending on the DSE version in use; e.g. DSE 5.1 may report two distinct workloads: Search and Analytics, while DSE 5.0 would report a single SearchAnalytics workload instead. It is up to users to deal with such discrepancies; the driver simply returns the workload labels as reported by DSE, without any form of pre-processing.
    The returned set is immutable. It is also possible for this information to be unavailable. In that case this method returns an empty set, and the caller should always be aware of this possibility.
    
    Returns:
    
    the DSE workloads the host is running.
  - isDseGraphEnabled
```
@Deprecated
public boolean isDseGraphEnabled()
```
    Deprecated. As of DSE 5.1, users should determine whether this host has the graph workload enabled by inspecting the contents of getDseWorkloads() instead. Note that this method will throw UnsupportedOperationException if the system tables do not contain a "graph" column.
    
    Returns whether the host is running DSE Graph.
    This is based on the "graph" column in system.local and system.peers.
    
    Returns:
    
    whether the node is running DSE Graph.
  - getHostId
```
public UUID getHostId()
```
    Return the host id value for the host.
    The host id is the main identifier used by Cassandra on the server for internal communication (gossip). It is referenced as the column host_id in the system.local or system.peers table.
    
    Returns:
    
    the node's host id value.
  - getSchemaVersion
```
public UUID getSchemaVersion()
```
    Return the current schema version for the host.
    Schema versions in Cassandra are used to ensure all the nodes agree on the current Cassandra schema when it is modified. For more information see ExecutionInfo.isSchemaInAgreement()
    
    Returns:
    
    the node's current schema version value.
  - getTokens
```
public Set<Token> getTokens()
```
    Returns the tokens that this host owns.
    
    Returns:
    
    the (immutable) set of tokens.
  - isUp
```
public boolean isUp()
```
    Returns whether the host is considered up by the driver.
    Please note that this is only the view of the driver and may not reflect reality. In particular a node can be down but the driver hasn't detected it yet, or it can have been restarted and the driver hasn't detected it yet (in particular, for hosts to which the driver does not connect (because the LoadBalancingPolicy.distance method says so), this information may be durably inaccurate). This information should thus only be considered as best effort and should not be relied upon too strongly.
    
    Returns:
    
    whether the node is considered up.
  - getState
```
public String getState()
```
    Returns a description of the host's state, as seen by the driver.
    This is exposed for debugging purposes only; the format of this string might change between driver versions, so clients should not make any assumptions about it.
    
    Returns:
    
    a description of the host's state.
  - getReconnectionAttemptFuture
```
public ListenableFuture<?> getReconnectionAttemptFuture()
```
    Returns a ListenableFuture representing the completion of the reconnection attempts scheduled after a host is marked DOWN.
    If the caller cancels this future, the driver will not try to reconnect to this host until it receives an UP event for it. Note that this could mean never, if the node was marked down because of a driver-side error (e.g. read timeout) but no failure was detected by Cassandra. The caller might decide to trigger an explicit reconnection attempt at a later point with tryReconnectOnce().
    
    Returns:
    
    the future, or null if no reconnection attempt was in progress.
  - tryReconnectOnce
```
public void tryReconnectOnce()
```
    Triggers an asynchronous reconnection attempt to this host.
    This method is intended for load balancing policies that mark hosts as IGNORED, but still need a way to periodically check these hosts' states (UP / DOWN).
    For a host that is at distance IGNORED, this method will try to reconnect exactly once: if reconnection succeeds, the host is marked UP; otherwise, no further attempts will be scheduled. It has no effect if the node is already UP, or if a reconnection attempt is already in progress.
    Note that if the host is not a distance IGNORED, this method will trigger a periodic reconnection attempt if the reconnection fails.
  - equals
```
public boolean equals(Object other)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Host

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

getAddress

getSocketAddress

getBroadcastAddress

getListenAddress

getDatacenter

getRack

getCassandraVersion

getDseVersion

getDseWorkload

getDseWorkloads

isDseGraphEnabled

getHostId

getSchemaVersion

getTokens

isUp

getState

getReconnectionAttemptFuture

tryReconnectOnce

equals

hashCode

toString