org.jrobin.core

Class Sample

public class Sample extends Object

Class to represent data source values for the given timestamp. Objects of this class are never created directly (no public constructor is provided). To learn more how to update RRDs, see RRDTool's rrdupdate man page.

To update a RRD with JRobin use the following procedure:

  1. Obtain empty Sample object by calling method createSample() on respective RrdDb object.
  2. Adjust Sample timestamp if necessary (see setTime() method).
  3. Supply data source values (see setValue()).
  4. Call Sample's update() method.

Newly created Sample object contains all data source values set to 'unknown'. You should specifify only 'known' data source values. However, if you want to specify 'unknown' values too, use Double.NaN.

Method Summary
Stringdump()
Dumps sample content using the syntax of RRDTool's update command.
String[]getDsNames()
Returns an array of all data source names.
longgetTime()
Returns sample timestamp (in seconds, without milliseconds).
double[]getValues()
Returns all current data source values in the sample.
Sampleset(String timeAndValues)

Sets sample timestamp and data source values in a fashion similar to RRDTool.

voidsetAndUpdate(String timeAndValues)

Creates sample with the timestamp and data source values supplied in the argument string and stores sample in the corresponding RRD.

SamplesetTime(long time)
Sets sample timestamp.
SamplesetValue(String dsName, double value)
Sets single data source value in the sample.
SamplesetValue(int i, double value)
Sets single datasource value using data source index.
SamplesetValues(double[] values)
Sets some (possibly all) data source values in bulk.
voidupdate()
Stores sample in the corresponding RRD.

Method Detail

dump

public String dump()
Dumps sample content using the syntax of RRDTool's update command.

Returns: Sample dump.

getDsNames

public String[] getDsNames()
Returns an array of all data source names. If you try to set value for the data source name not in this array, an exception is thrown.

Returns: Acceptable data source names.

getTime

public long getTime()
Returns sample timestamp (in seconds, without milliseconds).

Returns: Sample timestamp.

getValues

public double[] getValues()
Returns all current data source values in the sample.

Returns: Data source values.

set

public Sample set(String timeAndValues)

Sets sample timestamp and data source values in a fashion similar to RRDTool. Argument string should be composed in the following way: timestamp:value1:value2:...:valueN.

You don't have to supply all datasource values. Unspecified values will be treated as unknowns. To specify unknown value in the argument string, use letter 'U'

Parameters: timeAndValues String made by concatenating sample timestamp with corresponding data source values delmited with colons. For example:

                      1005234132:12.2:35.6:U:24.5
                      NOW:12.2:35.6:U:24.5
                      
'N' stands for the current timestamp (can be replaced with 'NOW')

Method will throw an exception if timestamp is invalid (cannot be parsed as Long, and is not 'N' or 'NOW'). Datasource value which cannot be parsed as 'double' will be silently set to NaN.

Returns: This Sample object

Throws: RrdException Thrown if too many datasource values are supplied

setAndUpdate

public void setAndUpdate(String timeAndValues)

Creates sample with the timestamp and data source values supplied in the argument string and stores sample in the corresponding RRD. This method is just a shortcut for:

     set(timeAndValues);
     update();
 

Parameters: timeAndValues String made by concatenating sample timestamp with corresponding data source values delmited with colons. For example:
1005234132:12.2:35.6:U:24.5
NOW:12.2:35.6:U:24.5

Throws: IOException Thrown in case of I/O error. RrdException Thrown in case of JRobin related error.

setTime

public Sample setTime(long time)
Sets sample timestamp. Timestamp should be defined in seconds (without milliseconds).

Parameters: time New sample timestamp.

Returns: This Sample object

setValue

public Sample setValue(String dsName, double value)
Sets single data source value in the sample.

Parameters: dsName Data source name. value Data source value.

Returns: This Sample object

Throws: RrdException Thrown if invalid data source name is supplied.

setValue

public Sample setValue(int i, double value)
Sets single datasource value using data source index. Data sources are indexed by the order specified during RRD creation (zero-based).

Parameters: i Data source index value Data source values

Returns: This Sample object

Throws: RrdException Thrown if data source index is invalid.

setValues

public Sample setValues(double[] values)
Sets some (possibly all) data source values in bulk. Data source values are assigned in the order of their definition inside the RRD.

Parameters: values Data source values.

Returns: This Sample object

Throws: RrdException Thrown if the number of supplied values is zero or greater than the number of data sources defined in the RRD.

update

public void update()
Stores sample in the corresponding RRD. If the update operation succeedes, all datasource values in the sample will be set to Double.NaN (unknown) values.

Throws: IOException Thrown in case of I/O error. RrdException Thrown in case of JRobin related error.