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

Class ChannelResponse

java.lang.Object

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

public class ChannelResponse
extends Object

Response object for the "get channel" 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
ChannelResponse(UUID channelDataId, String channelName, String controlSystemName, String controlSystemType, Map<Integer,Integer> decimationLevelToRetentionPeriod, boolean enabled, String errorMessage, Map<String,String> options, UUID serverId, String serverName, String state, Long totalSamplesDropped, Long totalSamplesSkippedBack, Long totalSamplesWritten) Creates a channel response.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
UUID	getChannelDataId() Returns the unique identifier that is associated with the data (samples) for the channel.
String	getChannelName() Returns the name of this channel.
String	getControlSystemName() Returns the name of the control-system support for this channel.
String	getControlSystemType() Returns the control-system type of this channel.
Map<Integer,Integer>	getDecimationLevelToRetentionPeriod() Returns a map that contains the retention periods of the decimation levels for the channel.
String	getErrorMessage() Returns the error message associated with the channel.
Map<String,String>	getOptions() Returns a map storing the configuration options for this channel.
UUID	getServerId() Returns the ID of the server that is responsible for this channel.
String	getServerName() Returns the name of the server that is responsible for this channel.
String	getState() Returns the state of the channel.
Long	getTotalSamplesDropped() Returns the total number of samples dropped for this channel.
Long	getTotalSamplesSkippedBack() Returns the total number of samples that were discarded because they skipped back in time.
Long	getTotalSamplesWritten() Returns the total number of samples written for this channel.
int	hashCode()
boolean	isEnabled() Tells whether archiving is enabled for this channel.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ChannelResponse

public ChannelResponse(UUID channelDataId,
                       String channelName,
                       String controlSystemName,
                       String controlSystemType,
                       Map<Integer,Integer> decimationLevelToRetentionPeriod,
                       boolean enabled,
                       String errorMessage,
                       Map<String,String> options,
                       UUID serverId,
                       String serverName,
                       String state,
                       Long totalSamplesDropped,
                       Long totalSamplesSkippedBack,
                       Long totalSamplesWritten)

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

Parameters:

channelDataId - unique identifier associated with the data (samples) for each channel. This identifier must be different for each channel. It is used instead of the channel name when storing data, so that the channel can be renamed later without losing data.

channelName - name of this channel. The name is a textual identifier that uniquely identifies the channel within the archive.

controlSystemName - human-readable name of the control-system used for this channel.

controlSystemType - control-system type of this channel. The control-system type defines the control-system that provides new data for the channel.

decimationLevelToRetentionPeriod - map that contains the retention periods of the decimation levels for the channel. The decimation levels are used as keys and the corresponding retention periods (in seconds) are stored as values. A retention period that is zero or negative means that samples for the corresponding decimation level are supposed to be retained forever.

enabled - true if archiving is enabled and the server should archive new samples received for the channel. false if archiving is disabled and the server should not archive new samples for the channel but just use the samples that have been archived previously.

errorMessage - error message associated with this channel. This parameter may be null. If the state is not ERROR, it must be null.

options - map storing the configuration options for this channel. The configuration options are passed on to the control-system specific adapter. The meaning of the options depends on this control-system specific code. The map should not contain null keys or values.

serverId - ID of the server that is responsible for this channel.

serverName - human-readable name of the server that is responsible for this channel. Typically, this is the hostname of the server.

state - state of the channel. One of the strings destroyed, disabled, disconnected, error initializing, or ok.

totalSamplesDropped - total number of samples that have been dropped (discarded) for the channel because they arrived to quickly and could not be written in time. This counter is reset when a channel is (re-)initialized (e.g. because its configuration has changed).

totalSamplesSkippedBack - total number of samples that have been dropped (discarded) because their time-stamp was less than or equal to a sample that was written earlier. This counter is reset when a channel is (re-)initialized (e.g. because its configuration has changed).

totalSamplesWritten - total number of samples that have been written (persisted) for this channel. This counter is reset when a channel is (re-)initialized (e.g. because its configuration has changed).

Method Detail

getChannelDataId

public UUID getChannelDataId()

Returns the unique identifier that is associated with the data (samples) for the channel. While a channel's name might change due to renaming, the data ID will be permanent (until the channel is deleted), so even after renaming a channel, its associated data can still be found.

Returns:

unique identifier associated with the channel's data.

getChannelName

public String getChannelName()

Returns the name of this channel. The name is a textual identifier that uniquely identifies the channel within the archive.

Returns:

channel name.

getControlSystemName

public String getControlSystemName()

Returns the name of the control-system support for this channel. The name is a human readable identifier for the control-system support.

Returns:

name of the control-system support for this channel.

getControlSystemType

public String getControlSystemType()

Returns the control-system type of this channel. The control-system type defines the control-system that provides new data for the channel.

Returns:

control-system type of the channel.

getDecimationLevelToRetentionPeriod

public Map<Integer,Integer> getDecimationLevelToRetentionPeriod()

Returns a map that contains the retention periods of the decimation levels for the channel. The decimation levels are as used keys and the corresponding retention periods (in seconds) are stored as values. A retention period that is zero or negative means that samples for the corresponding decimation level are supposed to be retained forever.

Returns:

map mapping decimation levels to their retention periods.

isEnabled

public boolean isEnabled()

Tells whether archiving is enabled for this channel. If true, archiving is enabled and the server should archive new samples received for the channel. If false, archiving is disabled and the server should not archive new samples for the channel but just use the samples that have been archived previously.

Returns:

true if archiving is enabled for this channel, false otherwise.

getErrorMessage

public String getErrorMessage()

Returns the error message associated with the channel. If the channel is not in the ERROR state, the error message is always null. Even if it is in the ERROR state, the error message is optional and might be null.

Returns:

error message associated with the channel or null if no error message is available.

getOptions

public Map<String,String> getOptions()

Returns a map storing the configuration options for this channel. The configuration options are passed on to the control-system specific adapter. The meaning of the options depends on this control-system specific code. The map does not contain null keys or values.

Returns:

map storing the configuration options for this channel.

getServerId

public UUID getServerId()

Returns the ID of the server that is responsible for this channel.

Returns:

ID of the server owning this channel.

getServerName

public String getServerName()

Returns the name of the server that is responsible for this channel. Typically, a server's name is the hostname of the machine on which the server is running.

Returns:

name of the server owning this channel.

getState

public String getState()

Returns the state of the channel. The state is identified by one of the strings destroyed, disabled, disconnected, error initializing, or ok. If status information is not available (e.g. because the responsible server is offline), null is returned.

Returns:

state of the channel or null if status information is not available.

getTotalSamplesDropped

public Long getTotalSamplesDropped()

Returns the total number of samples dropped for this channel. Samples are dropped when the queue of samples to be written grows too large. Typically, this happens when samples arrive faster than they can be written to the database. This counter is reset when a channel is (re-)initialized (e.g. because its configuration has changed). If status information is not available (e.g. because the responsible server is offline), null is returned.

Returns:

total number of samples dropped for this channel or null if status information is not available.

getTotalSamplesSkippedBack

public Long getTotalSamplesSkippedBack()

Returns the total number of samples that were discarded because they skipped back in time. Samples that have a time stamp that is less than or equal to the time stamp of a sample that haws already been written are considered to skip back in time. This might happen when a clock is not stable and skips back in time. However, it might also happen when a channel is disconnected and reconnects and the sample sent by the server is the same one that was already sent at an earlier point in time. This counter is reset when a channel is (re-)initialized (e.g. because its configuration has changed). If status information is not available (e.g. because the responsible server is offline), null is returned.

Returns:

total number of samples dropped for this channel or null if status information is not available.

getTotalSamplesWritten

public Long getTotalSamplesWritten()

Returns the total number of samples written for this channel. Samples are considered written after they have been successfully persisted to the database. This counter is reset when a channel is (re-)initialized (e.g. because its configuration has changed). If status information is not available (e.g. because the responsible server is offline), null is returned.

Returns:

total number of samples written for this channel or null if status information is not available.

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