db4o 2.0

com.db4o.ext
Class ExtDb4o

java.lang.Object
  |
  +--com.db4o.Db4o
        |
        +--com.db4o.ext.ExtDb4o

public final class ExtDb4o
extends Db4o

extended factory class with static methods to open special db4o sessions.


Method Summary
static ObjectContainer objectContainer(javax.servlet.ServletContext context, javax.servlet.http.HttpSession session, java.lang.String file)
          returns an ObjectContainer to be used in a stateless servlet session.
static ObjectContainer openMemoryFile(MemoryFile memoryFile)
          opens an ObjectContainer for in-memory use .
static ObjectContainer use(java.lang.Object jNLPRandomAccessFile)
           Java Web Start interface to open an ObjectContainer on a JNLPRandomAccessFile.
 
Methods inherited from class com.db4o.Db4o
configure, licensedTo, main, openClient, openClient, openFile, openServer, version
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

objectContainer

public static ObjectContainer objectContainer(javax.servlet.ServletContext context,
                                              javax.servlet.http.HttpSession session,
                                              java.lang.String file)
returns an ObjectContainer to be used in a stateless servlet session.

db4o internally takes care of all issues:
- returning the same ObjectContainer instance for every call with the same session parameter
- closing the ObjectContainer upon session termination
- closing the ObjectContainer upon shutdown
- closing and reopening the ObjectContainer in case servlet classes were exchanged and multiple ClassLoader namespaces exist.

Parameters:
context - the current ServletContext
session - the current HttpSession
file - the db4o database file to be used

openMemoryFile

public static final ObjectContainer openMemoryFile(MemoryFile memoryFile)
opens an ObjectContainer for in-memory use .

In-memory ObjectContainers are useful for maximum performance on small databases, for swapping objects or for storing db4o format data to other media or other databases.

Be aware of the danger of running into OutOfMemory problems or complete loss of all data, in case of hardware or JVM failures.

Parameters:
memoryFile - a MemoryFile to store the raw byte data.
Returns:
an open ObjectContainer
See Also:
MemoryFile

use

public static final ObjectContainer use(java.lang.Object jNLPRandomAccessFile)
Java Web Start interface to open an ObjectContainer on a JNLPRandomAccessFile.

Make sure the JNLPRandomAccessFile is opened for readwrite access and that sufficient filespace is reserved with FileContents.setMaxLength().

This feature is only available in db4o professional edition.

Parameters:
jNLPRandomAccessFile - a javax.jnlp.JNLPRandomAccessFile, typically opened with javax.jnlp.FileContents.getRandomAccessFile("rw");
Returns:
an open ObjectContainer

db4o 2.0