org.rrd4j.core

Class RrdMemoryBackendFactory

java.lang.Object

org.rrd4j.core.RrdBackendFactory

org.rrd4j.core.RrdMemoryBackendFactory

public class RrdMemoryBackendFactory
extends RrdBackendFactory

Factory class which creates actual RrdMemoryBackend objects. Rrd4j's support for in-memory RRDs is still experimental. You should know that all active RrdMemoryBackend objects are held in memory, each backend object stores RRD data in one big byte array. This implementation is therefore quite basic and memory hungry but runs very fast.

Calling close() on RrdDb objects does not release any memory at all (RRD data must be available for the next new RrdDb(path) call. To release allocated memory, you'll have to call delete(path) method of this class.

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<String,RrdMemoryBackend>	backends

Constructor Summary

Constructors

Constructor and Description
RrdMemoryBackendFactory()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	delete(String id) Removes the storage with the given ID from the memory.
protected boolean	exists(String id) Determines if a storage with the given path already exists.
String	getName() Returns the name of this factory.
protected RrdBackend	open(String id, boolean readOnly) Creates RrdBackend object for the given storage path.
protected boolean	shouldValidateHeader(String path) Determines if the header should be validated.

Methods inherited from class org.rrd4j.core.RrdBackendFactory

getDefaultFactory, getFactory, registerAndSetAsDefaultFactory, registerFactory, setDefaultFactory

Methods inherited from class java.lang.Object

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

Field Detail

backends

protected final Map<String,RrdMemoryBackend> backends

Constructor Detail

RrdMemoryBackendFactory

public RrdMemoryBackendFactory()

Method Detail

open

protected RrdBackend open(String id,
              boolean readOnly)
                   throws IOException

Creates RrdBackend object for the given storage path. Creates RrdMemoryBackend object.

Specified by:

open in class RrdBackendFactory

Parameters:

id - Storage path

readOnly - True, if the storage should be accessed in read/only mode. False otherwise.

Returns:

Backend object which handles all I/O operations for the given storage path

Throws:

IOException - Thrown in case of I/O error.

exists

protected boolean exists(String id)

Determines if a storage with the given path already exists. Method to determine if a memory storage with the given ID already exists.

Specified by:

exists in class RrdBackendFactory

Parameters:

id - Storage path

Returns:

a boolean.

shouldValidateHeader

protected boolean shouldValidateHeader(String path)
                                throws IOException

Determines if the header should be validated.

Specified by:

shouldValidateHeader in class RrdBackendFactory

Parameters:

path - Storage path

Returns:

a boolean.

Throws:

IOException - if header validation fails

delete

public boolean delete(String id)

Removes the storage with the given ID from the memory.

Parameters:

id - Storage ID

Returns:

a boolean.

getName

public String getName()

Returns the name of this factory.

Specified by:

getName in class RrdBackendFactory

Returns:

Factory name (equals to "MEMORY").