Package org.snmp4j.agent.db

Class MOXodusPersistenceProvider

java.lang.Object

org.snmp4j.agent.db.MOXodusPersistenceProvider

All Implemented Interfaces:

AutoCloseable, org.snmp4j.agent.io.MOPersistenceProvider, org.snmp4j.cfg.EngineBootsProvider, org.snmp4j.cfg.EngineIdProvider

public class MOXodusPersistenceProvider
extends Object
implements org.snmp4j.agent.io.MOPersistenceProvider, org.snmp4j.cfg.EngineBootsProvider, org.snmp4j.cfg.EngineIdProvider

The MOXodusPersistenceProvider implements a MOPersistenceProvider that uses a JetBrains Xodus database for persistent storage of RandomAccessManagedObjects. Using RandomAccessManagedObject persistence with this MOXodusPersistenceProvider has the following advantages:

• Less disk space usage than with DefaultMOPersistenceProvider
• Any Managed object changes are store via MOChangeListener and MOTableRowListener persistently into the database immediately.
• Concurrent access to storage is safe.

See MOServerPersistence for sample code and further usage details. To release the locks created on the Xodus database hold by the default persistence provider, close() need to be called explicitly.

Version:

3.7.2

Author:

Frank Fock

Constructor Summary

Constructors

Constructor	Description
MOXodusPersistenceProvider(MOXodusPersistence defaultPersistence)	Creates a MOXodusPersistenceProvider based with a provided default MOXodusPersistence handler that provides the default storage access operations and listens for RandomAccessManagedObject update events (see MOXodusPersistence.registerChangeListenersWithServer(MOServer) for details).

Method Summary

Modifier and Type	Method	Description
void	close()	Close the Xodus environment (DB) used by the default persistence located at getDefaultURI().
String	getDefaultURI()	Gets the URI of the default persistent storage for this provider.
int	getEngineBoots()	Returns current engine boot counter value.
org.snmp4j.smi.OctetString	getEngineId(org.snmp4j.smi.OctetString defaultEngineID)
String	getPersistenceProviderID()	Returns a unique ID of the persistence provider which should identify the format and type of the persistence provider.
boolean	isValidPersistenceURI(String uriString)	Checks whether the supplied URI string is valid for this persistence provider.
void	resetEngineId(org.snmp4j.smi.OctetString engineId)
void	restore(String uri, int importMode)	Restore (load) agent state from the specified URI (can be as simple as a file path).
void	restore(String uri, int importMode, org.snmp4j.agent.mo.MOPriorityProvider priorityProvider)	Restore (load) agent state from the specified URI (can be as simple as a file path).
void	store(String uri)	Stores the current agent state to persistent storage specified by the supplied URI.
void	store(String uri, org.snmp4j.agent.mo.MOPriorityProvider priorityProvider)
int	updateEngineBoots()	Returns the current engine boot counter value incremented by one.

Methods inherited from class java.lang.Object

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

Constructor Details

MOXodusPersistenceProvider

public MOXodusPersistenceProvider(MOXodusPersistence defaultPersistence)

Creates a MOXodusPersistenceProvider based with a provided default MOXodusPersistence handler that provides the default storage access operations and listens for RandomAccessManagedObject update events (see MOXodusPersistence.registerChangeListenersWithServer(MOServer) for details). Additional MOXodusPersistence can be created on the fly, with store(String).

Parameters:

defaultPersistence - the default persistence handler.

Method Details

restore

public void restore(String uri,
 int importMode)
             throws IOException

Restore (load) agent state from the specified URI (can be as simple as a file path).

Specified by:

restore in interface org.snmp4j.agent.io.MOPersistenceProvider

Parameters:

uri - a string pointing to the persistent storage from which the agent state should be restored from. The format of the string is specified by the persistence provider. A null value can be specified to let the persistence provider use its default URI. If that default URI is null too, a NullPointerException will be thrown.

importMode - specifies how the agent's current state should be update while restoring a previous state.

Throws:

IOException - if the restore operation fails.

Since:

1.2

restore

public void restore(String uri,
 int importMode,
 org.snmp4j.agent.mo.MOPriorityProvider priorityProvider)
             throws IOException

Restore (load) agent state from the specified URI (can be as simple as a file path).

Specified by:

restore in interface org.snmp4j.agent.io.MOPersistenceProvider

Parameters:

uri - a string pointing to the persistent storage from which the agent state should be restored from. The format of he string is specified by the persistence provider. A null value can be specified to let the persistence provider use its default URI. If that default URI is null too, a NullPointerException will be thrown.

importMode - specifies how the agent's current state should be update while restoring a previous state.

priorityProvider - if not null, this parameter specifies in which order the ManagedObjects are restored and which object contains the latest restore configuration which has to be restored at first to be able to restore the rest.

Throws:

IOException - if the restore operation fails.

Since:

3.5.0

store

public void store(String uri)
           throws IOException

Stores the current agent state to persistent storage specified by the supplied URI.

Specified by:

store in interface org.snmp4j.agent.io.MOPersistenceProvider

Parameters:

uri - a string pointing to the persistent storage from which the agent state should be stored to. The format of the string is specified by the persistence provider. A null value can be specified to let the persistence provider use its default URI. If that default URI is null too, a NullPointerException will be thrown.

Throws:

IOException - if the store operation fails.

Since:

1.2

store

public void store(String uri,
 org.snmp4j.agent.mo.MOPriorityProvider priorityProvider)
           throws IOException

Specified by:

store in interface org.snmp4j.agent.io.MOPersistenceProvider

Throws:

IOException

isValidPersistenceURI

public boolean isValidPersistenceURI(String uriString)

Checks whether the supplied URI string is valid for this persistence provider.

Specified by:

isValidPersistenceURI in interface org.snmp4j.agent.io.MOPersistenceProvider

Parameters:

uriString - a string identifying a persistent storage location for this storage provider.

Returns:

true if the uri is valid, false otherwise.

Since:

1.2

getPersistenceProviderID

public String getPersistenceProviderID()

Returns a unique ID of the persistence provider which should identify the format and type of the persistence provider.

Specified by:

getPersistenceProviderID in interface org.snmp4j.agent.io.MOPersistenceProvider

Returns:

an 1-32 character long string that identifies the persistence provider.

Since:

1.2

getDefaultURI

public String getDefaultURI()

Gets the URI of the default persistent storage for this provider.

Specified by:

getDefaultURI in interface org.snmp4j.agent.io.MOPersistenceProvider

Returns:

the URI (e.g. file path) for the default persistent storage location of this provider. A provider may use a different one. A null value indicates that there is no default location.

updateEngineBoots

public int updateEngineBoots()

Returns the current engine boot counter value incremented by one. If that number would by greater than 2^31-1 then one is returned. The engine boots provider has to make sure that the returned value is persistently stored before the method returns.

Specified by:

updateEngineBoots in interface org.snmp4j.cfg.EngineBootsProvider

Returns:

the last engine boots counter incremented by one.

getEngineBoots

public int getEngineBoots()

Returns current engine boot counter value.

Specified by:

getEngineBoots in interface org.snmp4j.cfg.EngineBootsProvider

Returns:

the last engine boots counter.

getEngineId

public org.snmp4j.smi.OctetString getEngineId(org.snmp4j.smi.OctetString defaultEngineID)

Specified by:

getEngineId in interface org.snmp4j.cfg.EngineIdProvider

resetEngineId

public void resetEngineId(org.snmp4j.smi.OctetString engineId)

Specified by:

resetEngineId in interface org.snmp4j.cfg.EngineIdProvider

close

public void close()
           throws Exception

Close the Xodus environment (DB) used by the default persistence located at getDefaultURI(). That environment is then no longer usable.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface org.snmp4j.agent.io.MOPersistenceProvider

Throws:

Exception - If there is an error on closing the environment. This should never happen with current Xodus releases.

Since:

3.7.2