org.osgi.service.dmt.spi

Interface TransactionalDataSession

All Superinterfaces:

ReadableDataSession, ReadWriteDataSession

public interface TransactionalDataSession
extends ReadWriteDataSession

Provides atomic read-write access to the part of the tree handled by the plugin that created this session.

Method Summary

Methods

Modifier and Type	Method and Description
void	commit() Commits a series of DMT operations issued in the current atomic session since the last transaction boundary.
void	rollback() Rolls back a series of DMT operations issued in the current atomic session since the last transaction boundary.

Methods inherited from interface org.osgi.service.dmt.spi.ReadWriteDataSession

copy, createInteriorNode, createLeafNode, deleteNode, renameNode, setNodeTitle, setNodeType, setNodeValue

Methods inherited from interface org.osgi.service.dmt.spi.ReadableDataSession

close, getChildNodeNames, getMetaNode, getNodeSize, getNodeTimestamp, getNodeTitle, getNodeType, getNodeValue, getNodeVersion, isLeafNode, isNodeUri, nodeChanged

Method Detail

commit

void commit()
            throws DmtException

Commits a series of DMT operations issued in the current atomic session since the last transaction boundary. Transaction boundaries are the creation of this object that starts the session, and all subsequent commit() and rollback() calls.

This method can fail even if all operations were successful. This can happen due to some multi-node semantic constraints defined by a specific implementation. For example, node A can be required to always have children A/B, A/C and A/D. If this condition is broken when commit() is executed, the method will fail, and throw a METADATA_MISMATCH exception.

In many cases the tree is not the only way to manage a given part of the system. It may happen that while modifying some nodes in an atomic session, the underlying settings are modified in parallel outside the scope of the DMT. If this is detected during commit, an exception with the code CONCURRENT_ACCESS is thrown.

Throws:

DmtException - with the following possible error codes

• METADATA_MISMATCH if the operation failed because of meta-data restrictions
• CONCURRENT_ACCESS if it is detected that some modification has been made outside the scope of the DMT to the nodes affected in the session's operations
• DATA_STORE_FAILURE if an error occurred while accessing the data store
• COMMAND_FAILED if some unspecified error is encountered while attempting to complete the command

SecurityException - if the caller does not have the necessary permissions to execute the underlying management operation

rollback

void rollback()
              throws DmtException

Rolls back a series of DMT operations issued in the current atomic session since the last transaction boundary. Transaction boundaries are the creation of this object that starts the session, and all subsequent commit() and rollback() calls.

Throws:

DmtException - with the error code ROLLBACK_FAILED in case the rollback did not succeed

SecurityException - if the caller does not have the necessary permissions to execute the underlying management operation