com.aquenos.cassandra.pvarchiver.server.web.admin.controller.wsapi

Class ServerStatusResponse

java.lang.Object

com.aquenos.cassandra.pvarchiver.server.web.admin.controller.wsapi.ServerStatusResponse

public class ServerStatusResponse
extends Object

Response object for the "server status" function of the web-service API.

This object is primarily intended to facilitate the JSON serialization of the data provided by the API controller. For this reason, it does not perform any checks on the parameters used to construct the object.

Author:

Sebastian Marsching

Constructor Summary

Constructors

Constructor and Description
ServerStatusResponse(String cassandraClusterName, String cassandraError, String cassandraKeyspaceName, int channelsDisconnected, int channelsError, int channelsTotal, UUID serverId, long serverLastOnlineTime, String serverName, boolean serverOnline, long totalSamplesDropped, long totalSamplesWritten) Creates a server status response.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
String	getCassandraClusterName() Returns the human-readable name of the Cassandra cluster to which this server is connected.
String	getCassandraError() Returns the error message indicating a problem that occurred while trying to connect to the Cassandra cluster.
String	getCassandraKeyspaceName() Returns the name of the Cassandra keyspace which is used by the Cassandra PV Archiver.
int	getChannelsDisconnected() Returns the number of channels that are in the disconnected state.
int	getChannelsError() Returns the number of channels that are in the error state.
int	getChannelsTotal() Returns the total number of channels on this server.
UUID	getServerId() Returns the ID of the server.
long	getServerLastOnlineTime() Returns the last time this server successfully registered itself with the cluster.
String	getServerName() Returns the human-readable name of the server.
long	getTotalSamplesDropped() Returns the total number of samples that have been dropped (discarded) by this server because they arrived to quickly and could not be written in time.
long	getTotalSamplesWritten() Returns the total number of samples that have been written (persisted) by this server.
int	hashCode()
boolean	isServerOnline() Tells whether the server considers itself to be online.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ServerStatusResponse

public ServerStatusResponse(String cassandraClusterName,
                            String cassandraError,
                            String cassandraKeyspaceName,
                            int channelsDisconnected,
                            int channelsError,
                            int channelsTotal,
                            UUID serverId,
                            long serverLastOnlineTime,
                            String serverName,
                            boolean serverOnline,
                            long totalSamplesDropped,
                            long totalSamplesWritten)

Creates a server status response. This constructor does not verify the validity of the arguments and simply uses them as-is.

Parameters:

cassandraClusterName - human-readable name of the Cassandra cluster to which this server is connected. May be null if the server is currently not connected to a Cassandra cluster. In this case, cassandraError is not null.

cassandraError - error message indicating a problem that occurred while trying to connect to the Cassandra cluster. This is null if there is no problem.

cassandraKeyspaceName - name of the Cassandra keyspace which is used by the Cassandra PV Archiver. May be null if the server is currently not connected to a Cassandra cluster. In this case, cassandraError is not null.

channelsDisconnected - number of channels that are in the disconnected state.

channelsError - number of channels that are in the error state.

channelsTotal - total number of channels on this server. If the server has not been initialized yet (e.g. because it cannot connect to the database), this number is zero, even if there are channels that belong to the server.

serverId - ID of the server.

serverLastOnlineTime - last time this server successfully registered itself with the cluster. The time is specified as the number of milliseconds since January 1st, 1970, 00:00:00 UTC. This number might be zero if the server has not successfully registered itself with the cluster since it was started.

serverName - human-readable name of the server. Typically, this is the hostname of the server.

serverOnline - flag indicating whether the server considers itself to be online. The server considers itself online when a sufficient amount of time has passed since successfully registering with the cluster and the renewal of the registration has not failed since.

totalSamplesDropped - total number of samples that have been dropped (discarded) by this server because they arrived to quickly and could not be written in time. This counter is reset when the server is restarted.

totalSamplesWritten - total number of samples that have been written (persisted) by this server. This counter is reset when the server is restarted.

Method Detail

getCassandraClusterName

public String getCassandraClusterName()

Returns the human-readable name of the Cassandra cluster to which this server is connected. May be null if the server is currently not connected to a Cassandra cluster. In this case, the value returned by getCassandraError() is not null.

Returns:

name of the Cassandra cluster or null if the name is not available.

getCassandraError

public String getCassandraError()

Returns the error message indicating a problem that occurred while trying to connect to the Cassandra cluster. This is null if there is no problem.

Returns:

error message describing why the connection to the Cassandra cluster cannot be established or null if there is no error.

getCassandraKeyspaceName

public String getCassandraKeyspaceName()

Returns the name of the Cassandra keyspace which is used by the Cassandra PV Archiver. May be null if the server is currently not connected to a Cassandra cluster. In this case, the value returned by getCassandraError() is not null.

Returns:

name of the Cassandra keyspace or null if the name is not available.

getChannelsDisconnected

public int getChannelsDisconnected()

Returns the number of channels that are in the disconnected state. Channels are disconnected if archiving is enabled, but the control-system support cannot establish the connection. Ultimately, it depends on the control-system support what constitutes the disconnected state. In general, a channel is considered disconnected when the control-system support cannot receive events for that channel, but considers the cause of this problem to be outside of the scope of the archiving system (e.g. the data source being temporarily unavailable).

Returns:

number of channels in the disconnected state.

getChannelsError

public int getChannelsError()

Returns the number of channels that are in the error state. A channel is put into the error state if the archive server detects an internal problem with this channel or if the channel’s control-system support reports an error when trying to initialize the channel.

Returns:

number of channels that are in the error state.

getChannelsTotal

public int getChannelsTotal()

Returns the total number of channels on this server. If the server has not been initialized yet (e.g. because it cannot connect to the database), this number is zero, even if there are channels that belong to the server.

Returns:

total number of channels.

getServerId

public UUID getServerId()

Returns the ID of the server. The server ID identifies a server within the cluster.

Returns:

ID of the server.

getServerLastOnlineTime

public long getServerLastOnlineTime()

Returns the last time this server successfully registered itself with the cluster. The time is specified as the number of milliseconds since January 1st, 1970, 00:00:00 UTC. This number might be zero if the server has not successfully registered itself with the cluster since it was started.

Returns:

last time the server successfully registered with the cluster.

getServerName

public String getServerName()

Returns the human-readable name of the server. Typically, a server's name is the hostname of the machine on which the server is running.

Returns:

server name.

isServerOnline

public boolean isServerOnline()

Tells whether the server considers itself to be online. The server considers itself online when a sufficient amount of time has passed since successfully registering with the cluster and the renewal of the registration has not failed since.

Returns:

true if the server is currently online, false if it is offline.

getTotalSamplesDropped

public long getTotalSamplesDropped()

Returns the total number of samples that have been dropped (discarded) by this server because they arrived to quickly and could not be written in time. This counter is reset when the server is restarted.

Returns:

total number of samples dropped by this server.

getTotalSamplesWritten

public long getTotalSamplesWritten()

Returns the total number of samples that have been written (persisted) by this server. This counter is reset when the server is restarted.

Returns:

total number of samples written by this server.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object