org.jrobin.core
Class Sample

java.lang.Object
  extended by org.jrobin.core.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.

Author:
Sasa Markovic

Method Summary
 String dump()
          Dumps sample content using the syntax of RRDTool's update command.
 String[] getDsNames()
          Returns an array of all data source names.
 long getTime()
          Returns sample timestamp (in seconds, without milliseconds).
 double[] getValues()
          Returns all current data source values in the sample.
 Sample set(String timeAndValues)
          Sets sample timestamp and data source values in a fashion similar to RRDTool.
 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.
 Sample setTime(long time)
          Sets sample timestamp.
 Sample setValue(int i, double value)
          Sets single datasource value using data source index.
 Sample setValue(String dsName, double value)
          Sets single data source value in the sample.
 Sample setValues(double[] values)
          Sets some (possibly all) data source values in bulk.
 void update()
          Stores sample in the corresponding RRD.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

setValue

public Sample setValue(String dsName,
                       double value)
                throws RrdException
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)
                throws RrdException
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)
                 throws RrdException
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.

getValues

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

Returns:
Data source values.

getTime

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

Returns:
Sample timestamp.

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

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.

set

public Sample set(String timeAndValues)
           throws RrdException

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

update

public void update()
            throws IOException,
                   RrdException
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.

setAndUpdate

public void setAndUpdate(String timeAndValues)
                  throws IOException,
                         RrdException

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.

dump

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

Returns:
Sample dump.


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