RrdDb (RRD4J 2.2 API)

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

```
public class RrdDb
extends Object
```
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

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.

Constructor Summary

Constructors
Constructor and Description
`RrdDb(RrdDef rrdDef)` Constructor used to create new RRD object from the definition.
`RrdDb(RrdDef rrdDef, RrdBackendFactory factory)` Constructor used to create new RRD object from the definition object but with a storage (backend) different from default.
`RrdDb(String path)` Constructor used to open already existing RRD in R/W mode, with a default storage (backend) type (file on the disk).
`RrdDb(String path, boolean readOnly)` Constructor used to open already existing RRD.
`RrdDb(String path, boolean readOnly, RrdBackendFactory factory)` Constructor used to open already existing RRD backed with a storage (backend) different from default.
`RrdDb(String path, RrdBackendFactory factory)` Constructor used to open already existing RRD in R/W mode with a storage (backend) type different from default.
`RrdDb(String rrdPath, String externalPath)` Constructor used to create RRD files from external file sources.
`RrdDb(String rrdPath, String externalPath, RrdBackendFactory factory)` Constructor used to create RRD files from external file sources with a backend type different from default.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` Closes RRD.
`boolean`	`containsDs(String dsName)` Checks presence of a specific datasource.
`void`	`copyStateTo(org.rrd4j.core.RrdUpdater other)` 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.
`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.
`protected void`	`finalize()`
`Archive`	`findMatchingArchive(FetchRequest request)`
`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.
`int`	`getArcIndex(ConsolFun consolFun, int steps)` Returns index of Archive object with the given consolidation function and the number of steps.
`byte[]`	`getBytes()` Returns an array of bytes representing the whole RRD.
`String`	`getCanonicalPath()` Returns canonical path to the underlying RRD file.
`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.
`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()`
`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 path to this RRD.
`org.rrd4j.core.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.
`String`	`getXml()` Returns string representing internal RRD state in XML format.
`boolean`	`isClosed()` Returns true if the RRD is closed.
`static void`	`main(String[] args)`
`static void`	`setDefaultFactory(String factoryName)` Sets default backend factory to be used.
`void`	`setInfo(String info)`

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

- Field Detail
  - 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
  - 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
- Constructor Detail
  - RrdDb
```
public RrdDb(RrdDef rrdDef)
      throws IOException
```
    Constructor used to create new RRD object from the definition. 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 constructor 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 = new RrdDb(def);
 // new RRD file has been created on your disk
 
```
    Parameters:
    rrdDef - Object describing the structure of the new RRD file.
    
    Throws:
    
    IOException - Thrown in case of I/O error.
  - RrdDb
```
public RrdDb(RrdDef rrdDef,
     RrdBackendFactory factory)
      throws IOException
```
    Constructor used to create new RRD object from the definition object but with a storage (backend) different from default.
    Rrd4j uses factories to create RRD backend objects. There are three different backend factories supplied with Rrd4j, and each factory has its unique name:
    - FILE: backends created from this factory will store RRD data to files by using java.io.* classes and methods
    - NIO: backends created from this factory will store RRD data to files by using java.nio.* classes and methods
    - MEMORY: backends created from this factory will store RRD data in memory. This might be useful in runtime environments which prohibit disk utilization, or for storing temporary, non-critical data (it gets lost as soon as JVM exits).
    For example, to create RRD in memory, use the following code
```
 RrdBackendFactory factory = RrdBackendFactory.getFactory("MEMORY");
 RrdDb rrdDb = new RrdDb(rrdDef, factory);
 rrdDb.close();
 
```
    New RRD file structure is specified with an object of class RrdDef. The underlying RRD storage is created as soon as the constructor returns.
    Parameters:
    rrdDef - RRD definition object
    factory - The factory which will be used to create storage for this RRD
    
    Throws:
    
    IOException - Thrown in case of I/O error
    See Also:
    RrdBackendFactory
  - RrdDb
```
public RrdDb(String path,
     boolean readOnly)
      throws IOException
```
    Constructor used to open already existing RRD. This RRD object will be backed with a storage (backend) of the default type (file on the disk). Constructor obtains read or read/write access to this RRD.
    
    Parameters:
    path - Path to existing RRD.
    readOnly - Should be set to false if you want to update the underlying RRD. If you want just to fetch data from the RRD file (read-only access), specify true. If you try to update RRD file open in read-only mode (readOnly set to true), IOException will be thrown.
    
    Throws:
    
    IOException - Thrown in case of I/O error.
  - RrdDb
```
public RrdDb(String path,
     boolean readOnly,
     RrdBackendFactory factory)
      throws IOException
```
    Constructor used to open already existing RRD backed with a storage (backend) different from default. Constructor obtains read or read/write access to this RRD.
    
    Parameters:
    path - Path to existing RRD.
    readOnly - Should be set to false if you want to update the underlying RRD. If you want just to fetch data from the RRD file (read-only access), specify true. If you try to update RRD file open in read-only mode (readOnly set to true), IOException will be thrown.
    factory - Backend factory which will be used for this RRD.
    
    Throws:
    
    FileNotFoundException - Thrown if the requested file does not exist.
    
    IOException - Thrown in case of general I/O error (bad RRD file, for example).
    See Also:
    RrdBackendFactory
  - RrdDb
```
public RrdDb(String path)
      throws IOException
```
    Constructor used to open already existing RRD in R/W mode, with a default storage (backend) type (file on the disk).
    
    Parameters:
    path - Path to existing RRD.
    
    Throws:
    
    IOException - Thrown in case of I/O error.
  - RrdDb
```
public RrdDb(String path,
     RrdBackendFactory factory)
      throws IOException
```
    Constructor used to open already existing RRD in R/W mode with a storage (backend) type different from default.
    
    Parameters:
    path - Path to existing RRD.
    factory - Backend factory used to create this RRD.
    
    Throws:
    
    IOException - Thrown in case of I/O error.
    See Also:
    RrdBackendFactory
  - RrdDb
```
public RrdDb(String rrdPath,
     String externalPath)
      throws IOException
```
    Constructor used to create RRD files from external file sources. Supported external file sources are:
    - RRDTool/Rrd4j XML file dumps (i.e files created with rrdtool dump command).
    - RRDTool binary files.
    Newly created RRD will be backed with a default storage (backend) type (file on the disk).
    
    Rrd4j and RRDTool use the same format for XML dump and this constructor should be used to (re)create Rrd4j RRD files from XML dumps. First, dump the content of a RRDTool RRD file (use command line):
```
 rrdtool dump original.rrd > original.xml
 
```
    Than, use the file original.xml to create Rrd4j RRD file named copy.rrd:
```
 RrdDb rrd = new RrdDb("copy.rrd", "original.xml");
 
```
    or:
```
 RrdDb rrd = new RrdDb("copy.rrd", "xml:/original.xml");
 
```
    See documentation for dumpXml() method to see how to convert Rrd4j files to RRDTool's format.
    
    To read RRDTool files directly, specify rrdtool:/ prefix in the externalPath argument. For example, to create Rrd4j compatible file named copy.rrd from the file original.rrd created with RRDTool, use the following code:
```
 RrdDb rrd = new RrdDb("copy.rrd", "rrdtool:/original.rrd");
 
```
    Note that the prefix xml:/ or rrdtool:/ is necessary to distinguish between XML and RRDTool's binary sources. If no prefix is supplied, XML format is assumed
    Parameters:
    rrdPath - Path to a RRD file which will be created
    externalPath - Path to an external file which should be imported, with an optional xml:/ or rrdtool:/ prefix.
    
    Throws:
    
    IOException - Thrown in case of I/O error
  - RrdDb
```
public RrdDb(String rrdPath,
     String externalPath,
     RrdBackendFactory factory)
      throws IOException
```
    Constructor used to create RRD files from external file sources with a backend type different from default. Supported external file sources are:
    - RRDTool/Rrd4j XML file dumps (i.e files created with rrdtool dump command).
    - RRDTool binary files.
    Rrd4j and RRDTool use the same format for XML dump and this constructor should be used to (re)create Rrd4j RRD files from XML dumps. First, dump the content of a RRDTool RRD file (use command line):
```
 rrdtool dump original.rrd > original.xml
 
```
    Than, use the file original.xml to create Rrd4j RRD file named copy.rrd:
```
 RrdDb rrd = new RrdDb("copy.rrd", "original.xml");
 
```
    or:
```
 RrdDb rrd = new RrdDb("copy.rrd", "xml:/original.xml");
 
```
    See documentation for dumpXml() method to see how to convert Rrd4j files to RRDTool's format.
    
    To read RRDTool files directly, specify rrdtool:/ prefix in the externalPath argument. For example, to create Rrd4j compatible file named copy.rrd from the file original.rrd created with RRDTool, use the following code:
```
 RrdDb rrd = new RrdDb("copy.rrd", "rrdtool:/original.rrd");
 
```
    Note that the prefix xml:/ or rrdtool:/ is necessary to distinguish between XML and RRDTool's binary sources. If no prefix is supplied, XML format is assumed
    Parameters:
    rrdPath - Path to RRD which will be created
    externalPath - Path to an external file which should be imported, with an optional xml:/ or rrdtool:/ prefix.
    factory - Backend factory which will be used to create storage (backend) for this RRD.
    
    Throws:
    
    IOException - Thrown in case of I/O error
    See Also:
    RrdBackendFactory
- Method Detail
  - close
```
public void close()
           throws IOException
```
    Closes RRD. No further operations are allowed on this RrdDb object.
    
    Throws:
    
    IOException - Thrown in case of I/O related error.
  - isClosed
```
public boolean isClosed()
```
    Returns true if the RRD is closed.
    
    Returns:
    true if closed, false otherwise
  - getHeader
```
public Header getHeader()
```
    Returns RRD header.
    
    Returns:
    Header object
  - getDatasource
```
public Datasource getDatasource(int dsIndex)
```
    Returns Datasource object for the given datasource index.
    
    Parameters:
    dsIndex - Datasource index (zero based)
    
    Returns:
    Datasource object
  - getArchive
```
public Archive getArchive(int arcIndex)
```
    Returns Archive object for the given archive index.
    
    Parameters:
    arcIndex - Archive index (zero based)
    
    Returns:
    Archive object
  - 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.
  - 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.
  - 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.
  - 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. Allowed values are "AVERAGE", "MIN", "MAX" and "LAST" (these constants are conveniently defined in the ConsolFun class).
    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
  - 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. Allowed values are AVERAGE, MIN, MAX, FIRST, LAST and TOTAL (see ConsolFun enum).
    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.
  - findMatchingArchive
```
public Archive findMatchingArchive(FetchRequest request)
                            throws IOException
```
    Throws:
    
    IOException
  - 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.
  - 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.
  - 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.
  - 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.
  - 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
  - exportXml
```
public void exportXml(OutputStream destination)
               throws IOException
```
    This method is just an alias for dumpXml method.
    
    Throws:
    
    IOException - Thrown in case of I/O related error
  - 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
  - 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
  - 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.
  - exportXml
```
public void exportXml(String filename)
               throws IOException
```
    This method is just an alias for dumpXml(String) method.
    
    Throws:
    
    IOException - Thrown in case of I/O related 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
  - 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
  - finalize
```
protected void finalize()
                 throws Throwable
```
    Overrides:
    
    finalize in class Object
    
    Throws:
    
    Throwable
  - copyStateTo
```
public void copyStateTo(org.rrd4j.core.RrdUpdater other)
                 throws IOException
```
    Copies object's internal state to another RrdDb object.
    
    Parameters:
    other - New RrdDb object to copy state to
    
    Throws:
    
    IOException - Thrown in case of I/O error
  - 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
  - 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
  - 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
  - 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.
  - getPath
```
public String getPath()
```
    Returns path to this RRD.
    
    Returns:
    Path to this RRD.
  - getRrdBackend
```
public RrdBackend getRrdBackend()
```
    Returns backend object for this RRD which performs actual I/O operations.
    
    Returns:
    RRD backend for this RRD.
  - getRrdAllocator
```
public org.rrd4j.core.RrdAllocator getRrdAllocator()
```
    Required to implement RrdUpdater interface. You should never call this method directly.
    
    Returns:
    Allocator object
  - 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.
  - setDefaultFactory
```
public static void setDefaultFactory(String factoryName)
```
    Sets default backend factory to be used. This method is just an alias for RrdBackendFactory.setDefaultFactory(String).
    
    Parameters:
    factoryName - Name of the backend factory to be set as default.
    
    Throws:
    
    IllegalArgumentException - Thrown if invalid factory name is supplied, or not called before the first backend object (before the first RrdDb object) is created.
  - 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
  - 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
  - getDsCount
```
public int getDsCount()
```
    Returns the number of datasources defined in the file
    
    Returns:
    The number of datasources defined in the file
  - getArcCount
```
public int getArcCount()
```
    Returns the number of RRA archives defined in the file
    
    Returns:
    The number of RRA archives defined in the file
  - 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
  - getInfo
```
public String getInfo()
               throws IOException
```
    Throws:
    
    IOException
  - setInfo
```
public void setInfo(String info)
             throws IOException
```
    Throws:
    
    IOException
  - main
```
public static void main(String[] args)
```

Class RrdDb

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PREFIX_XML

PREFIX_RRDTool

Constructor Detail

RrdDb

RrdDb

RrdDb

RrdDb

RrdDb

RrdDb

RrdDb

RrdDb

Method Detail

close

isClosed

getHeader

getDatasource

getArchive

getDsNames

createSample

createSample

createFetchRequest

createFetchRequest

findMatchingArchive

findStartMatchArchive

dump

getDsIndex

containsDs

dumpXml

exportXml

getXml

exportXml

dumpXml

exportXml

getLastUpdateTime

getRrdDef

finalize

copyStateTo

getDatasource

getArcIndex

getArchive

getCanonicalPath

getPath

getRrdBackend

getRrdAllocator

getBytes

setDefaultFactory

getLastDatasourceValues

getLastDatasourceValue

getDsCount

getArcCount

getLastArchiveUpdateTime

getInfo

setInfo

main