Package org.rrd4j.core

Class Sample

java.lang.Object
org.rrd4j.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 Rrd4j 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 specify only 'known' data source values. However, if you want to specify 'unknown' values too, use Double.NaN.

Author:
Sasa Markovic

  • Constructor Summary

    Constructors 
    Constructor Description
    Sample​(RrdDb parentDb, long time)  

  • Method Summary

    Modifier and Type Method Description
    String dump()
    Dumps sample content using the syntax of RRDTool's update command.
    String[] getDsNames()
    Returns an array of all data source names.
    (package private) String getRrdToolCommand()  
    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

  • Constructor Details

  • Method Details

    • 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:
      IllegalArgumentException - 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:
      IllegalArgumentException - 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:
      IllegalArgumentException - 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)

      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:
      IllegalArgumentException - Thrown if too many datasource values are supplied

    • update

      public void update() throws IOException
      Stores sample in the corresponding RRD. If the update operation succeeds, all datasource values in the sample will be set to Double.NaN (unknown) values.
      Throws:
      IOException - Thrown in case of I/O error.

    • setAndUpdate

      public void setAndUpdate​(String timeAndValues) throws IOException
      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.

    • dump

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

    • getRrdToolCommand

      String getRrdToolCommand()