java.lang.Object
org.rrd4j.core.RobinMatrix
All Implemented Interfaces:
Robin, RrdUpdater<Robin>
class RobinMatrixextends Object implements Robin
Class to represent archive values for a single datasource. Robin class is the heart of the so-called "round robin database" concept. Basically, each Robin object is a fixed length array of double values. Each double value represents consolidated, archived value for the specific timestamp. When the underlying array of double values gets completely filled, new values will replace the oldest ones.

Robin object does not hold values in memory - such object could be quite large. Instead of it, Robin reads them from the backend I/O only when necessary.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final int
    column
    Which column of the archive this matrix holds.
    private final Archive
    parentArc
    The archive whose values are stored.
    private final RrdInt<Archive>
    pointer
    Where the next row is written.
    private final int
    rows
    How many rows the ring holds.
    private final RrdDoubleMatrix<Archive>
    values
    The stored rows, in a ring.

  • Constructor Summary

    Constructors
    Constructor
    Description
    RobinMatrix(Archive parentArc, RrdDoubleMatrix<Archive> values, RrdInt<Archive> pointer, int column)
    Create robin matrix

  • Method Summary

    All Methods
    Modifier and Type
    Method
    Description
    void
    bulkStore(double newValue, int bulkCount)
    Appends one value repeatedly, for bulk updates.
    void
    copyStateTo(Robin robin)
    Copies object's internal state to another Robin object.
    String
    dump()
    Renders the stored rows as a single line of formatted values.
    void
    filterValues(double minValue, double maxValue)
    Filters values stored in this archive based on the given boundary.
    Archive
    getParent()
    Returns the Archive object to which this Robin object belongs.
    RrdAllocator
    getRrdAllocator()
    Required to implement RrdUpdater interface.
    RrdBackend
    getRrdBackend()
    Returns the underlying storage (backend) object which actually performs all I/O operations.
    int
    getSize()
    Returns the size of the underlying array of archived values.
    double
    getValue(int index)
    Returns the i-th value from the Robin archive.
    double[]
    getValues()
    Fetches all archived values.
    double[]
    getValues(int index, int count)
    Reads a run of values starting at a row index.
    void
    setValue(int index, double value)
    Sets the i-th value in the Robin archive.
    void
    setValues(double newValue)
    (Re)sets all values in this archive to the same value.
    void
    setValues(double... newValues)
    Updates archived values in bulk.
    void
    store(double newValue)
    Appends a single value at the current row pointer.
    void
    update(double[] newValues)
    Stores one complete set of row values and rewinds the write pointer.

    Methods inherited from class Object

    clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • parentArc

      private final Archive parentArc
      The archive whose values are stored.

    • pointer

      private final RrdInt<Archive> pointer
      Where the next row is written.

    • values

      private final RrdDoubleMatrix<Archive> values
      The stored rows, in a ring.

    • rows

      private final int rows
      How many rows the ring holds.

    • column

      private final int column
      Which column of the archive this matrix holds.

  • Constructor Details

    • RobinMatrix

      RobinMatrix(Archive parentArc, RrdDoubleMatrix<Archive> values, RrdInt<Archive> pointer, int column)
      Create robin matrix
      Parameters:
      parentArc - the archive this matrix is bound to, holding the rows to be consolidated
      values - the backend matrix of archived values, whose row count sets the number of slots
      pointer - the shared rotating index of the slot to overwrite with the next stored value
      column - the zero-based datasource column this matrix reads and writes

  • Method Details

    • getValues

      public double[] getValues() throws IOException
      Fetches all archived values.
      Specified by:
      getValues in interface Robin
      Returns:
      Array of double archive values, starting from the oldest one.
      Throws:
      IOException - Thrown in case of I/O specific error.

    • store

      public void store(double newValue) throws IOException
      Appends a single value at the current row pointer.
      Specified by:
      store in interface Robin
      Parameters:
      newValue - a double.
      Throws:
      IOException - Thrown in case of I/O error

    • bulkStore

      public void bulkStore(double newValue, int bulkCount) throws IOException
      Appends one value repeatedly, for bulk updates.
      Specified by:
      bulkStore in interface Robin
      Parameters:
      newValue - a double.
      bulkCount - a int.
      Throws:
      IOException - Thrown in case of I/O error

    • update

      public void update(double[] newValues) throws IOException
      Stores one complete set of row values and rewinds the write pointer.
      Specified by:
      update in interface Robin
      Parameters:
      newValues - an array of double.
      Throws:
      IOException - Thrown in case of I/O error

    • setValues

      public void setValues(double... newValues) throws IOException
      Updates archived values in bulk.

      Updates archived values in bulk.

      Specified by:
      setValues in interface Robin
      Parameters:
      newValues - Array of double values to be stored in the archive
      Throws:
      IOException - Thrown in case of I/O error

    • setValues

      public void setValues(double newValue) throws IOException
      (Re)sets all values in this archive to the same value.

      (Re)sets all values in this archive to the same value.

      Specified by:
      setValues in interface Robin
      Parameters:
      newValue - New value
      Throws:
      IOException - Thrown in case of I/O error

    • dump

      public String dump() throws IOException
      Renders the stored rows as a single line of formatted values.
      Specified by:
      dump in interface Robin
      Returns:
      a String object.
      Throws:
      IOException - Thrown in case of I/O error

    • getValue

      public double getValue(int index) throws IOException
      Returns the i-th value from the Robin archive.

      Returns the i-th value from the Robin archive.

      Specified by:
      getValue in interface Robin
      Parameters:
      index - Value index
      Returns:
      Value stored in the i-th position (the oldest value has zero index)
      Throws:
      IOException - Thrown in case of I/O specific error.

    • setValue

      public void setValue(int index, double value) throws IOException
      Sets the i-th value in the Robin archive.

      Sets the i-th value in the Robin archive.

      Specified by:
      setValue in interface Robin
      Parameters:
      index - index in the archive (the oldest value has zero index)
      value - value to be stored
      Throws:
      IOException - Thrown in case of I/O specific error.

    • getValues

      public double[] getValues(int index, int count) throws IOException
      Reads a run of values starting at a row index.
      Specified by:
      getValues in interface Robin
      Parameters:
      index - a int.
      count - a int.
      Returns:
      an array of double.
      Throws:
      IOException - Thrown in case of I/O error

    • getParent

      public Archive getParent()
      Returns the Archive object to which this Robin object belongs.
      Specified by:
      getParent in interface Robin
      Returns:
      Parent Archive object

    • getSize

      public int getSize()
      Returns the size of the underlying array of archived values.
      Specified by:
      getSize in interface Robin
      Returns:
      Number of stored values

    • copyStateTo

      public void copyStateTo(Robin robin) throws IOException

      Copies object's internal state to another Robin object.

      Copies object's internal state to another Robin object.

      Specified by:
      copyStateTo in interface Robin
      Specified by:
      copyStateTo in interface RrdUpdater<Robin>
      Parameters:
      robin - a RrdUpdater object.
      Throws:
      IOException - if the state cannot be read from the backend

    • filterValues

      public void filterValues(double minValue, double maxValue) throws IOException
      Filters values stored in this archive based on the given boundary. Archived values found to be outside of [minValue, maxValue] interval (inclusive) will be silently replaced with NaN.

      Filters values stored in this archive based on the given boundary. Archived values found to be outside of [minValue, maxValue] interval (inclusive) will be silently replaced with NaN.

      Specified by:
      filterValues in interface Robin
      Parameters:
      minValue - inclusive lower bound; values below it become NaN
      maxValue - inclusive upper bound; values above it become NaN
      Throws:
      IOException - Thrown in case of I/O error

    • getRrdBackend

      public RrdBackend getRrdBackend()
      Returns the underlying storage (backend) object which actually performs all I/O operations.
      Specified by:
      getRrdBackend in interface Robin
      Specified by:
      getRrdBackend in interface RrdUpdater<Robin>
      Returns:
      I/O backend object

    • getRrdAllocator

      public RrdAllocator getRrdAllocator()
      Required to implement RrdUpdater interface. You should never call this method directly.
      Specified by:
      getRrdAllocator in interface Robin
      Specified by:
      getRrdAllocator in interface RrdUpdater<Robin>
      Returns:
      Allocator object