RrdDbPool (I2P Anonymous Network - Java Documentation

java.lang.Object
- org.jrobin.core.RrdDbPool

```
public class RrdDbPool
extends Object
```
This class should be used to synchronize access to RRD files in a multithreaded environment. This class should be also used to prevent openning of too many RRD files at the same time (thus avoiding operating system limits)

Field Summary

Fields
Modifier and Type Field Description

static int INITIAL_CAPACITY
Initial capacity of the pool i.e.

Fields
Modifier and Type	Field	Description
`static int`	`INITIAL_CAPACITY`	Initial capacity of the pool i.e.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`getCapacity()`	Returns the maximum number of simultaneously open RRD files.
`static RrdDbPool`	`getInstance()`	Creates a single instance of the class on the first call, or returns already existing one.
`int`	`getOpenFileCount()`	Returns the number of open RRD files.
`String[]`	`getOpenFiles()`	Returns an array of open file names.
`void`	`release(RrdDb rrdDb)`	Releases RrdDb reference previously obtained from the pool.
`RrdDb`	`requestRrdDb(String path)`	Requests a RrdDb reference for the given RRD file path.
`RrdDb`	`requestRrdDb(String path, String sourcePath)`	Requests a RrdDb reference for the given path.
`RrdDb`	`requestRrdDb(RrdDef rrdDef)`	Requests a RrdDb reference for the given RRD file definition object.
`void`	`setCapacity(int capacity)`	Sets the maximum number of simultaneously open RRD files.

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

- Field Detail
  - INITIAL_CAPACITY
```
public static final int INITIAL_CAPACITY
```
    Initial capacity of the pool i.e. maximum number of simultaneously open RRD files. The pool will never open too many RRD files at the same time.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - getInstance
```
public static RrdDbPool getInstance()
                             throws RrdException
```
    Creates a single instance of the class on the first call, or returns already existing one.
    
    Returns:
    
    Single instance of this class
    
    Throws:
    
    RrdException - Thrown if the default RRD backend is not derived from the RrdFileBackendFactory
  - requestRrdDb
```
public RrdDb requestRrdDb(String path)
                   throws IOException,
                          RrdException
```
    Requests a RrdDb reference for the given RRD file path.
    - If the file is already open, previously returned RrdDb reference will be returned. Its usage count will be incremented by one.
    - If the file is not already open and the number of already open RRD files is less than INITIAL_CAPACITY, the file will be open and a new RrdDb reference will be returned. If the file is not already open and the number of already open RRD files is equal to INITIAL_CAPACITY, the method blocks until some RRD file is closed.
    Parameters:
    
    path - Path to existing RRD file
    
    Returns:
    
    reference for the give RRD file
    
    Throws:
    
    IOException - Thrown in case of I/O error
    
    RrdException - Thrown in case of JRobin specific error
  - requestRrdDb
```
public RrdDb requestRrdDb(RrdDef rrdDef)
                   throws IOException,
                          RrdException
```
    Requests a RrdDb reference for the given RRD file definition object.
    - If the file with the path specified in the RrdDef object is already open, the method blocks until the file is closed.
    - If the file is not already open and the number of already open RRD files is less than INITIAL_CAPACITY, a new RRD file will be created and a its RrdDb reference will be returned. If the file is not already open and the number of already open RRD files is equal to INITIAL_CAPACITY, the method blocks until some RRD file is closed.
    Parameters:
    
    rrdDef - Definition of the RRD file to be created
    
    Returns:
    
    Reference to the newly created RRD file
    
    Throws:
    
    IOException - Thrown in case of I/O error
    
    RrdException - Thrown in case of JRobin specific error
  - requestRrdDb
```
public RrdDb requestRrdDb(String path,
                          String sourcePath)
                   throws IOException,
                          RrdException,
                          RrdException
```
    Requests a RrdDb reference for the given path. The file will be created from external data (from XML dump, RRD file or RRDTool's binary RRD file).
    - If the file with the path specified is already open, the method blocks until the file is closed.
    - If the file is not already open and the number of already open RRD files is less than INITIAL_CAPACITY, a new RRD file will be created and a its RrdDb reference will be returned. If the file is not already open and the number of already open RRD files is equal to INITIAL_CAPACITY, the method blocks until some RRD file is closed.
    Parameters:
    
    path - Path to RRD file which should be created
    
    sourcePath - Path to external data which is to be converted to JRobin's native RRD file format
    
    Returns:
    
    Reference to the newly created RRD file
    
    Throws:
    
    IOException - Thrown in case of I/O error
    
    RrdException - Thrown in case of JRobin specific error
  - release
```
public void release(RrdDb rrdDb)
             throws IOException,
                    RrdException
```
    Releases RrdDb reference previously obtained from the pool. When a reference is released, its usage count is decremented by one. If usage count drops to zero, the underlying RRD file will be closed.
    
    Parameters:
    
    rrdDb - RrdDb reference to be returned to the pool
    
    Throws:
    
    IOException - Thrown in case of I/O error
    
    RrdException - Thrown in case of JRobin specific error
  - getCapacity
```
public int getCapacity()
```
    Returns the maximum number of simultaneously open RRD files.
    
    Returns:
    
    maximum number of simultaneously open RRD files
  - setCapacity
```
public void setCapacity(int capacity)
```
    Sets the maximum number of simultaneously open RRD files.
    
    Parameters:
    
    capacity - Maximum number of simultaneously open RRD files.
  - getOpenFiles
```
public String[] getOpenFiles()
```
    Returns an array of open file names.
    
    Returns:
    
    Array with canonical paths to open RRD files held in the pool.
  - getOpenFileCount
```
public int getOpenFileCount()
```
    Returns the number of open RRD files.
    
    Returns:
    
    Number of currently open RRD files held in the pool.

Class RrdDbPool

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INITIAL_CAPACITY

Method Detail

getInstance

requestRrdDb

requestRrdDb

requestRrdDb

release

getCapacity

setCapacity

getOpenFiles

getOpenFileCount