RrdDb (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- org.rrd4j.core.RrdDb

All Implemented Interfaces:
Closeable, AutoCloseable, RrdUpdater<RrdDb>
```
public class RrdDb
extends Object
implements RrdUpdater<RrdDb>, Closeable
```
Main class used to create and manipulate round robin databases (RRDs). Use this class to perform update and fetch operations on existing RRDs, to create new RRD from the definition (object of class RrdDef) or from XML file (dumped content of RRDTool's or Rrd4j's RRD file).
Each RRD is backed with some kind of storage. For example, RRDTool supports only one kind of storage (disk file). On the contrary, Rrd4j gives you freedom to use other storage (backend) types even to create your own backend types for some special purposes. Rrd4j by default stores RRD data in files (as RRDTool), but you might choose to store RRD data in memory (this is supported in Rrd4j), to use java.nio.* instead of java.io.* package for file manipulation (also supported) or to store whole RRDs in the SQL database (you'll have to extend some classes to do this).
Note that Rrd4j uses binary format different from RRDTool's format. You cannot use this class to manipulate RRD files created with RRDTool. However, if you perform the same sequence of create, update and fetch operations, you will get exactly the same results from Rrd4j and RRDTool.
You will not be able to use Rrd4j API if you are not familiar with basic RRDTool concepts. Good place to start is the official RRD tutorial and relevant RRDTool man pages: rrdcreate, rrdupdate, rrdfetch and rrdgraph. For RRDTool's advanced graphing capabilities (RPN extensions), also supported in Rrd4j, there is an excellent CDEF tutorial.
See Also:
RrdBackend, RrdBackendFactory

Nested Class Summary
Nested Classes
Modifier and Type Class and Description
static class RrdDb.Builder
Builder for RrdDb instances.

Nested Classes
Modifier and Type	Class and Description
`static class`	`RrdDb.Builder` Builder for `RrdDb` instances.

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`PREFIX_RRDTool` Prefix to identify external RRDTool file source used in various RrdDb constructors.
`static String`	`PREFIX_XML` Prefix to identify external XML file source used in various RrdDb constructors.
`(package private) static int`	`XML_BUFFER_CAPACITY` XML buffer capacity in bytes

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) void`	`archive(Datasource datasource, double value, double lastValue, long numUpdates)` Archive value
`void`	`close()` Closes RRD.
`boolean`	`containsDs(String dsName)` Checks presence of a specific datasource.
`void`	`copyStateTo(RrdDb otherRrd)` Copies object's internal state to another RrdDb object.
`FetchRequest`	`createFetchRequest(ConsolFun consolFun, long fetchStart, long fetchEnd)` Prepares fetch request to be executed on this RRD.
`FetchRequest`	`createFetchRequest(ConsolFun consolFun, long fetchStart, long fetchEnd, long resolution)` Prepares fetch request to be executed on this RRD.
`Sample`	`createSample()` Creates new sample with the current timestamp and all data source values set to 'unknown'.
`Sample`	`createSample(long time)` Creates new sample with the given timestamp and all datasource values set to 'unknown'.
`String`	`dump()` Returns string representing complete internal RRD state.
`void`	`dumpXml(OutputStream destination)` Writes the RRD content to `OutputStream` using XML format.
`void`	`dumpXml(String filename)` Dumps internal RRD state to XML file.
`void`	`dumpXml(XmlWriter writer)` Writes the RRD content to `XmlWriter` using XML format.
`String`	`exportXml()` This method is just an alias for `getXml` method.
`void`	`exportXml(OutputStream destination)` This method is just an alias for `dumpXml` method.
`void`	`exportXml(String filename)` This method is just an alias for `dumpXml(String)` method.
`(package private) FetchData`	`fetchData(FetchRequest request)` Fetch data
`Archive`	`findMatchingArchive(FetchRequest request)` findMatchingArchive.
`Archive`	`findStartMatchArchive(String consolFun, long startTime, long resolution)` Finds the archive that best matches to the start time (time period being start-time until now) and requested resolution.
`int`	`getArcCount()` Returns the number of RRA archives defined in the file
`Archive`	`getArchive(ConsolFun consolFun, int steps)` Returns Archive object with the given consolidation function and the number of steps.
`Archive`	`getArchive(int arcIndex)` Returns Archive object for the given archive index.
`(package private) Archive[]`	`getArchives()` Archives.
`int`	`getArcIndex(ConsolFun consolFun, int steps)` Returns index of Archive object with the given consolidation function and the number of steps.
`static RrdDb.Builder`	`getBuilder()` Create a new builder for constructing RrdDb instances.
`byte[]`	`getBytes()` Returns an array of bytes representing the whole RRD.
`String`	`getCanonicalPath()` Returns canonical path to the underlying RRD file.
`URI`	`getCanonicalUri()` Returns the canonical URI for this RRD.
`Datasource`	`getDatasource(int dsIndex)` Returns Datasource object for the given datasource index.
`Datasource`	`getDatasource(String dsName)` Returns Datasource object corresponding to the given datasource name.
`(package private) Datasource[]`	`getDatasources()` Datasources.
`int`	`getDsCount()` Returns the number of datasources defined in the file
`int`	`getDsIndex(String dsName)` Returns internal index number for the given datasource name.
`String[]`	`getDsNames()` Returns an array of datasource names defined in RRD.
`Header`	`getHeader()` Returns RRD header.
`String`	`getInfo()` getInfo.
`long`	`getLastArchiveUpdateTime()` Returns the last time when some of the archives in this RRD was updated.
`double`	`getLastDatasourceValue(String dsName)` Returns the last stored value for the given datasource.
`double[]`	`getLastDatasourceValues()` Returns an array of last datasource values.
`long`	`getLastUpdateTime()` Returns time of last update operation as timestamp (in seconds).
`String`	`getPath()` Returns the path to this RRD.
`RrdAllocator`	`getRrdAllocator()` Required to implement RrdUpdater interface.
`RrdBackend`	`getRrdBackend()` Returns backend object for this RRD which performs actual I/O operations.
`RrdDef`	`getRrdDef()` Returns RRD definition object which can be used to create new RRD with the same creation parameters but with no data in it.
`URI`	`getUri()` Returns the URI to this RRD, as seen by the backend.
`String`	`getXml()` Returns string representing internal RRD state in XML format.
`(package private) void`	`internalClose()` Internal close
`boolean`	`isClosed()` Returns true if the RRD is closed.
`static RrdDb`	`of(RrdDef rrdDef)` Returns a new RRD object from the definition.
`static RrdDb`	`of(String path)` Opens an existing RRD with read/write access.
`static RrdDb`	`of(URI uri)` Opens an existing RRD with read/write access.
`void`	`setInfo(String info)` setInfo.
`(package private) void`	`store(Sample sample)` Store sample

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - PREFIX_RRDTool
```
public static final String PREFIX_RRDTool
```
    Prefix to identify external RRDTool file source used in various RrdDb constructors.
    See Also:
    Constant Field Values
  - PREFIX_XML
```
public static final String PREFIX_XML
```
    Prefix to identify external XML file source used in various RrdDb constructors.
    See Also:
    Constant Field Values
  - XML_BUFFER_CAPACITY
```
static final int XML_BUFFER_CAPACITY
```
    XML buffer capacity in bytes
    See Also:
    Constant Field Values
- Method Detail
  - archive
```
final void archive(Datasource datasource,
                   double value,
                   double lastValue,
                   long numUpdates)
            throws IOException
```
    Archive value
    Throws:
    IOException
  - close
```
public void close()
           throws IOException
```
    Closes RRD. No further operations are allowed on this RrdDb object.
    Specified by:
    close in interface Closeable
    Specified by:
    close in interface AutoCloseable
    Throws:
    IOException - Thrown in case of I/O related error.
    IllegalStateException - if the thread was interrupted in pool usage.
  - containsDs
```
public boolean containsDs(String dsName)
                   throws IOException
```
    Checks presence of a specific datasource.
    Parameters:
    dsName - Datasource name to check
    Returns:
    true if datasource is present in this RRD, false otherwise
    Throws:
    IOException - Thrown in case of I/O error.
  - copyStateTo
```
public void copyStateTo(RrdDb otherRrd)
                 throws IOException
```
    Copies object's internal state to another RrdDb object.
    Specified by:
    copyStateTo in interface RrdUpdater<RrdDb>
    Parameters:
    otherRrd - the target RrdDb
    Throws:
    IOException - if an I/O error occurs
  - createFetchRequest
```
public FetchRequest createFetchRequest(ConsolFun consolFun,
                                       long fetchStart,
                                       long fetchEnd)
```
    Prepares fetch request to be executed on this RRD. Use returned FetchRequest object and its fetchData() method to actually fetch data from this RRD. Data will be fetched with the smallest possible resolution (see RRDTool's rrdfetch man page for the explanation of the resolution parameter).
    Parameters:
    consolFun - Consolidation function to be used in fetch request.
    fetchStart - Starting timestamp for fetch request.
    fetchEnd - Ending timestamp for fetch request.
    Returns:
    Request object that should be used to actually fetch data from RRD.
  - createFetchRequest
```
public FetchRequest createFetchRequest(ConsolFun consolFun,
                                       long fetchStart,
                                       long fetchEnd,
                                       long resolution)
```
    Prepares fetch request to be executed on this RRD. Use returned FetchRequest object and its fetchData() method to actually fetch data from the RRD file.
    Parameters:
    consolFun - Consolidation function to be used in fetch request.
    fetchStart - Starting timestamp for fetch request.
    fetchEnd - Ending timestamp for fetch request.
    resolution - Fetch resolution (see RRDTool's rrdfetch man page for an explanation of this parameter.
    Returns:
    Request object that should be used to actually fetch data from RRD
  - createSample
```
public Sample createSample()
                    throws IOException
```
    Creates new sample with the current timestamp and all data source values set to 'unknown'. Use returned Sample object to specify datasource values for the current timestamp. See documentation for Sample for an explanation how to do this.
    Once populated with data source values, call Sample's update() method to actually store sample in the RRD associated with it.
    Returns:
    Fresh sample with the current timestamp and all data source values set to 'unknown'.
    Throws:
    IOException - Thrown in case of I/O error.
  - createSample
```
public Sample createSample(long time)
                    throws IOException
```
    Creates new sample with the given timestamp and all datasource values set to 'unknown'. Use returned Sample object to specify datasource values for the given timestamp. See documentation for Sample for an explanation how to do this.
    Once populated with data source values, call Sample's update() method to actually store sample in the RRD associated with it.
    Parameters:
    time - Sample timestamp rounded to the nearest second (without milliseconds).
    Returns:
    Fresh sample with the given timestamp and all data source values set to 'unknown'.
    Throws:
    IOException - Thrown in case of I/O error.
  - dump
```
public String dump()
            throws IOException
```
    Returns string representing complete internal RRD state. The returned string can be printed to stdout and/or used for debugging purposes.
    Returns:
    String representing internal RRD state.
    Throws:
    IOException - Thrown in case of I/O related error.
  - dumpXml
```
public void dumpXml(OutputStream destination)
             throws IOException
```
    Writes the RRD content to OutputStream using XML format. This format is fully compatible with RRDTool's XML dump format and can be used for conversion purposes or debugging.
    Parameters:
    destination - Output stream to receive XML data
    Throws:
    IOException - Thrown in case of I/O related error
  - dumpXml
```
public void dumpXml(String filename)
             throws IOException
```
    Dumps internal RRD state to XML file. Use this XML file to convert your Rrd4j RRD to RRDTool format.
    Suppose that you have a Rrd4j RRD file original.rrd and you want to convert it to RRDTool format. First, execute the following java code: RrdDb rrd = new RrdDb("original.rrd"); rrd.dumpXml("original.xml");
    Use original.xml file to create the corresponding RRDTool file (from your command line):
    rrdtool restore copy.rrd original.xml
    Parameters:
    filename - Path to XML file which will be created.
    Throws:
    IOException - Thrown in case of I/O related error.
  - dumpXml
```
public void dumpXml(XmlWriter writer)
             throws IOException
```
    Writes the RRD content to XmlWriter using XML format. This format is fully compatible with RRDTool's XML dump format and can be used for conversion purposes or debugging.
    Parameters:
    writer - XmlWriter to receive XML data
    Throws:
    IOException - Thrown in case of I/O related error
  - exportXml
```
public String exportXml()
                 throws IOException
```
    This method is just an alias for getXml method.
    Returns:
    Internal RRD state in XML format.
    Throws:
    IOException - Thrown in case of I/O related error
  - exportXml
```
public void exportXml(OutputStream destination)
               throws IOException
```
    This method is just an alias for dumpXml method.
    Parameters:
    destination - a OutputStream object.
    Throws:
    IOException - Thrown in case of I/O related error
  - exportXml
```
public void exportXml(String filename)
               throws IOException
```
    This method is just an alias for dumpXml(String) method.
    Parameters:
    filename - a String object.
    Throws:
    IOException - Thrown in case of I/O related error
  - fetchData
```
FetchData fetchData(FetchRequest request)
             throws IOException
```
    Fetch data
    Throws:
    IOException
  - findMatchingArchive
```
public Archive findMatchingArchive(FetchRequest request)
                            throws IOException
```
    findMatchingArchive.
    Parameters:
    request - a FetchRequest object.
    Returns:
    a Archive object.
    Throws:
    IOException - if any.
  - findStartMatchArchive
```
public Archive findStartMatchArchive(String consolFun,
                                     long startTime,
                                     long resolution)
                              throws IOException
```
    Finds the archive that best matches to the start time (time period being start-time until now) and requested resolution.
    Parameters:
    consolFun - Consolidation function of the datasource.
    startTime - Start time of the time period in seconds.
    resolution - Requested fetch resolution.
    Returns:
    Reference to the best matching archive.
    Throws:
    IOException - Thrown in case of I/O related error.
  - getArcCount
```
public int getArcCount()
```
    Returns the number of RRA archives defined in the file
    Returns:
    The number of RRA archives defined in the file
  - getArchive
```
public Archive getArchive(ConsolFun consolFun,
                          int steps)
                   throws IOException
```
    Returns Archive object with the given consolidation function and the number of steps.
    Parameters:
    consolFun - Consolidation function
    steps - Number of archive steps
    Returns:
    Requested Archive object or null if no such archive could be found
    Throws:
    IOException - Thrown in case of I/O error
  - getArchive
```
public Archive getArchive(int arcIndex)
```
    Returns Archive object for the given archive index.
    Parameters:
    arcIndex - Archive index (zero based)
    Returns:
    Archive object
  - getArchives
```
Archive[] getArchives()
```
    Archives.
    Returns:
    the archives
  - getArcIndex
```
public int getArcIndex(ConsolFun consolFun,
                       int steps)
                throws IOException
```
    Returns index of Archive object with the given consolidation function and the number of steps. Exception is thrown if such archive could not be found.
    Parameters:
    consolFun - Consolidation function
    steps - Number of archive steps
    Returns:
    Requested Archive object
    Throws:
    IOException - Thrown in case of I/O error
  - getBuilder
```
public static RrdDb.Builder getBuilder()
```
    Create a new builder for constructing RrdDb instances.
    Returns:
    a Builder
  - getBytes
```
public byte[] getBytes()
                throws IOException
```
    Returns an array of bytes representing the whole RRD.
    Returns:
    All RRD bytes
    Throws:
    IOException - Thrown in case of I/O related error.
  - getCanonicalPath
```
public String getCanonicalPath()
                        throws IOException
```
    Returns canonical path to the underlying RRD file. Note that this method makes sense just for ordinary RRD files created on the disk - an exception will be thrown for RRD objects created in memory or with custom backends.
    Returns:
    Canonical path to RRD file;
    Throws:
    IOException - Thrown in case of I/O error or if the underlying backend is not derived from RrdFileBackend.
  - getCanonicalUri
```
public URI getCanonicalUri()
```
    Returns the canonical URI for this RRD.
    Returns:
    the canonical URI
  - getDatasource
```
public Datasource getDatasource(int dsIndex)
```
    Returns Datasource object for the given datasource index.
    Parameters:
    dsIndex - Datasource index (zero based)
    Returns:
    Datasource object
  - getDatasource
```
public Datasource getDatasource(String dsName)
                         throws IOException
```
    Returns Datasource object corresponding to the given datasource name.
    Parameters:
    dsName - Datasource name
    Returns:
    Datasource object corresponding to the give datasource name or null if not found.
    Throws:
    IOException - Thrown in case of I/O error
  - getDatasources
```
Datasource[] getDatasources()
```
    Datasources.
    Returns:
    the datasources
  - getDsCount
```
public int getDsCount()
```
    Returns the number of datasources defined in the file
    Returns:
    The number of datasources defined in the file
  - getDsIndex
```
public int getDsIndex(String dsName)
               throws IOException
```
    Returns internal index number for the given datasource name.
    Parameters:
    dsName - Data source name.
    Returns:
    Internal index of the given data source name in this RRD.
    Throws:
    IOException - Thrown in case of I/O error.
  - getDsNames
```
public String[] getDsNames()
                    throws IOException
```
    Returns an array of datasource names defined in RRD.
    Returns:
    Array of datasource names.
    Throws:
    IOException - Thrown in case of I/O error.
  - getHeader
```
public Header getHeader()
```
    Returns RRD header.
    Returns:
    Header object
  - getInfo
```
public String getInfo()
               throws IOException
```
    getInfo.
    Returns:
    a String object.
    Throws:
    IOException - if any.
  - getLastArchiveUpdateTime
```
public long getLastArchiveUpdateTime()
                              throws IOException
```
    Returns the last time when some of the archives in this RRD was updated. This time is not the same as the getLastUpdateTime() since RRD file can be updated without updating any of the archives.
    Returns:
    last time when some of the archives in this RRD was updated
    Throws:
    IOException - Thrown in case of I/O error
  - getLastDatasourceValue
```
public double getLastDatasourceValue(String dsName)
                              throws IOException
```
    Returns the last stored value for the given datasource.
    Parameters:
    dsName - Datasource name
    Returns:
    Last stored value for the given datasource
    Throws:
    IOException - Thrown in case of I/O error
    IllegalArgumentException - Thrown if no datasource in this RrdDb matches the given datasource name
  - getLastDatasourceValues
```
public double[] getLastDatasourceValues()
                                 throws IOException
```
    Returns an array of last datasource values. The first value in the array corresponds to the first datasource defined in the RrdDb and so on.
    Returns:
    Array of last datasource values
    Throws:
    IOException - Thrown in case of I/O error
  - getLastUpdateTime
```
public long getLastUpdateTime()
                       throws IOException
```
    Returns time of last update operation as timestamp (in seconds).
    Returns:
    Last update time (in seconds).
    Throws:
    IOException - if any.
  - getPath
```
public String getPath()
```
    Returns the path to this RRD.
    Returns:
    Path to this RRD.
  - getRrdAllocator
```
public RrdAllocator getRrdAllocator()
```
    Required to implement RrdUpdater interface. You should never call this method directly.
    Specified by:
    getRrdAllocator in interface RrdUpdater<RrdDb>
    Returns:
    Allocator object
  - getRrdBackend
```
public RrdBackend getRrdBackend()
```
    Returns backend object for this RRD which performs actual I/O operations.
    Specified by:
    getRrdBackend in interface RrdUpdater<RrdDb>
    Returns:
    RRD backend for this RRD.
  - getRrdDef
```
public RrdDef getRrdDef()
                 throws IOException
```
    Returns RRD definition object which can be used to create new RRD with the same creation parameters but with no data in it.
    Example:
```
 RrdDb rrd1 = new RrdDb("original.rrd");
 RrdDef def = rrd1.getRrdDef();
 // fix path
 def.setPath("empty_copy.rrd");
 // create new RRD file
 RrdDb rrd2 = new RrdDb(def);
 
```
    Returns:
    RRD definition.
    Throws:
    IOException - if any.
  - getUri
```
public URI getUri()
```
    Returns the URI to this RRD, as seen by the backend.
    Returns:
    URI to this RRD.
  - getXml
```
public String getXml()
              throws IOException
```
    Returns string representing internal RRD state in XML format. This format is fully compatible with RRDTool's XML dump format and can be used for conversion purposes or debugging.
    Returns:
    Internal RRD state in XML format.
    Throws:
    IOException - Thrown in case of I/O related error
  - internalClose
```
void internalClose()
            throws IOException
```
    Internal close
    Throws:
    IOException
  - isClosed
```
public boolean isClosed()
```
    Returns true if the RRD is closed.
    Returns:
    true if closed, false otherwise
  - of
```
public static RrdDb of(RrdDef rrdDef)
                throws IOException
```
    Returns a new RRD object from the definition. If the rrdDef was constructed giving an URI, RrdBackendFactory.findFactory(URI) will be used to resolve the needed factory. If not, or a relative URI was given, this RRD object will be backed with a storage (backend) of the default type. Initially, storage type defaults to "NIO" (RRD bytes will be put in a file on the disk). Default storage type can be changed with a static RrdBackendFactory.setDefaultFactory(String) method call.
    New RRD file structure is specified with an object of class RrdDef. The underlying RRD storage is created as soon as the method returns.
    Typical scenario:
```
 // create new RRD definition
 RrdDef def = new RrdDef("test.rrd", 300);
 def.addDatasource("input", DsType.DT_COUNTER, 600, 0, Double.NaN);
 def.addDatasource("output", DsType.DT_COUNTER, 600, 0, Double.NaN);
 def.addArchive(ConsolFun.CF_AVERAGE, 0.5, 1, 600);
 def.addArchive(ConsolFun.CF_AVERAGE, 0.5, 6, 700);
 def.addArchive(ConsolFun.CF_AVERAGE, 0.5, 24, 797);
 def.addArchive(ConsolFun.CF_AVERAGE, 0.5, 288, 775);
 def.addArchive(ConsolFun.CF_MAX, 0.5, 1, 600);
 def.addArchive(ConsolFun.CF_MAX, 0.5, 6, 700);
 def.addArchive(ConsolFun.CF_MAX, 0.5, 24, 797);
 def.addArchive(ConsolFun.CF_MAX, 0.5, 288, 775);

 // RRD definition is now completed, create the database!
 RrdDb rrd = RrdDb.of(def);
 // new RRD file has been created on your disk
 
```
    Parameters:
    rrdDef - Object describing the structure of the new RRD file.
    Returns:
    a new Rrdb created from the definition.
    Throws:
    IOException - Thrown in case of I/O error.
  - of
```
public static RrdDb of(String path)
                throws IOException
```
    Opens an existing RRD with read/write access. The path will be parsed as an URI and checked against the active factories. If it's a relative URI (no scheme given, or just a plain path), the default factory will be used.
    Parameters:
    path - Path to existing RRD.
    Returns:
    a {link RrdDb} opened with default settings
    Throws:
    IOException - Thrown in case of I/O error.
  - of
```
public static RrdDb of(URI uri)
                throws IOException
```
    Opens an existing RRD with read/write access. The URI will checked against the active factories. If it's a relative URI (no scheme given, or just a plain path), the default factory will be used.
    Parameters:
    uri - URI to existing RRD.
    Returns:
    a {link RrdDb} opened with default settings
    Throws:
    IOException - Thrown in case of I/O error.
  - setInfo
```
public void setInfo(String info)
             throws IOException
```
    setInfo.
    Parameters:
    info - a String object.
    Throws:
    IOException - if any.
  - store
```
final void store(Sample sample)
          throws IOException
```
    Store sample
    Throws:
    IOException

Class RrdDb

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PREFIX_RRDTool

PREFIX_XML

XML_BUFFER_CAPACITY

Method Detail

archive

close

containsDs

copyStateTo

createFetchRequest

createFetchRequest

createSample

createSample

dump

dumpXml

dumpXml

dumpXml

exportXml

exportXml

exportXml

fetchData

findMatchingArchive

findStartMatchArchive

getArcCount

getArchive

getArchive

getArchives

getArcIndex

getBuilder

getBytes

getCanonicalPath

getCanonicalUri

getDatasource

getDatasource

getDatasources

getDsCount

getDsIndex

getDsNames

getHeader

getInfo

getLastArchiveUpdateTime

getLastDatasourceValue

getLastDatasourceValues

getLastUpdateTime

getPath

getRrdAllocator

getRrdBackend

getRrdDef

getUri

getXml

internalClose

isClosed

of

of

of

setInfo

store