org.apache.directory.server.core.changelog
Interface ChangeLog

public interface ChangeLog

A facade for the change log subsystem. It exposes the functionality needed to interact with the facility to query for changes, take snapshots, and revert the server to an earlier revision.

Version:

$Rev$, $Date$

Author:

Apache Directory Project

Method Summary

void	destroy() Destroy the changeLog
ChangeLogSearchEngine	getChangeLogSearchEngine() Gets the change log query engine which would be used to ask questions about what changed, when, how and by whom.
ChangeLogStore	getChangeLogStore()
long	getCurrentRevision() Gets the current revision for the server.
Tag	getLatest()
TagSearchEngine	getTagSearchEngine() Gets the tag search engine used to query the snapshots taken.
void	init(DirectoryService service) Initialize the ChangeLog system.
boolean	isEnabled() Checks whether or not the change log has been enabled to track changes.
boolean	isExposed()
boolean	isLogSearchSupported() Returns whether or not this ChangeLogService supports searching for changes.
boolean	isTagSearchSupported() Returns whether or not this ChangeLogService supports searching for snapshot tags.
boolean	isTagStorageSupported() Returns whether or not this ChangeLogService stores snapshot tags.
ChangeLogEvent	log(LdapPrincipal principal, org.apache.directory.shared.ldap.ldif.LdifEntry forward, org.apache.directory.shared.ldap.ldif.LdifEntry reverse) Records a change as a forward LDIF, a reverse change to revert the change and the authorized principal triggering the revertable change event.
ChangeLogEvent	log(LdapPrincipal principal, org.apache.directory.shared.ldap.ldif.LdifEntry forward, java.util.List<org.apache.directory.shared.ldap.ldif.LdifEntry> reverses) Records a change as a forward LDIF, some reverse changes to revert the change and the authorized principal triggering the revertable change event.
void	setChangeLogStore(ChangeLogStore store) Set the underlying storage
void	setEnabled(boolean enabled) Enable or disable the ChangeLog service
void	setExposed(boolean exposed) Exposes the contents of ChangeLog to clients if set to true.
void	setPartitionSuffix(java.lang.String suffix) The prefix of the partition.
void	setRevisionsContainerName(java.lang.String revContainerName) The name of the revisions container under the partition.
void	setTagsContainerName(java.lang.String tagContainerName) The name of the tags container under the partition.
void	sync() Flush the changes to disk
Tag	tag() Creates a snapshot of the server at the current revision.
Tag	tag(long revision) Creates a tag for a snapshot of the server in a specific state at a revision.
Tag	tag(long revision, java.lang.String description) Creates a tag for a snapshot of the server in a specific state at a revision.
Tag	tag(java.lang.String description) Creates a snapshot of the server at the current revision.

Method Detail

isEnabled

boolean isEnabled()

Checks whether or not the change log has been enabled to track changes.

Returns:

true if the change log is tracking changes, false otherwise

setEnabled

void setEnabled(boolean enabled)

Enable or disable the ChangeLog service

Parameters:

enabled - true to enable the service, flase to disable it

getChangeLogStore

ChangeLogStore getChangeLogStore()

Returns:

The underlying storage

setChangeLogStore

void setChangeLogStore(ChangeLogStore store)

Set the underlying storage

Parameters:

store - The storage

getCurrentRevision

long getCurrentRevision()
                        throws java.lang.Exception

Gets the current revision for the server.

Returns:

the current revision

Throws:

java.lang.Exception - if there is a problem accessing this information

log

ChangeLogEvent log(LdapPrincipal principal,
                   org.apache.directory.shared.ldap.ldif.LdifEntry forward,
                   org.apache.directory.shared.ldap.ldif.LdifEntry reverse)
                   throws java.lang.Exception

Records a change as a forward LDIF, a reverse change to revert the change and the authorized principal triggering the revertable change event.

Parameters:

principal - the authorized LDAP principal triggering the change

forward - LDIF of the change going to the next state

reverse - LDIF (anti-operation): the change required to revert this change

Returns:

the new revision reached after having applied the forward LDIF

Throws:

java.lang.Exception - if there are problems logging the change

log

ChangeLogEvent log(LdapPrincipal principal,
                   org.apache.directory.shared.ldap.ldif.LdifEntry forward,
                   java.util.List<org.apache.directory.shared.ldap.ldif.LdifEntry> reverses)
                   throws java.lang.Exception

Records a change as a forward LDIF, some reverse changes to revert the change and the authorized principal triggering the revertable change event.

Parameters:

principal - the authorized LDAP principal triggering the change

forward - LDIF of the change going to the next state

reverses - LDIF (anti-operation): the changes required to revert this change

Returns:

the new revision reached after having applied the forward LDIF

Throws:

java.lang.Exception - if there are problems logging the change

isLogSearchSupported

boolean isLogSearchSupported()

Returns whether or not this ChangeLogService supports searching for changes.

Returns:

true if log searching is supported, false otherwise

isTagSearchSupported

boolean isTagSearchSupported()

Returns whether or not this ChangeLogService supports searching for snapshot tags.

Returns:

true if snapshot tag searching is supported, false otherwise

isTagStorageSupported

boolean isTagStorageSupported()

Returns whether or not this ChangeLogService stores snapshot tags.

Returns:

true if this ChangeLogService supports tag storage, false otherwise

getChangeLogSearchEngine

ChangeLogSearchEngine getChangeLogSearchEngine()

Gets the change log query engine which would be used to ask questions about what changed, when, how and by whom. It may not be supported by all implementations. Some implementations may simply log changes without direct access to those changes from within the server.

Returns:

the change log query engine

Throws:

java.lang.UnsupportedOperationException - if the change log is not searchable

getTagSearchEngine

TagSearchEngine getTagSearchEngine()

Gets the tag search engine used to query the snapshots taken. If this ChangeLogService does not support a taggable and searchable store then an UnsupportedOperationException will result.

Returns:

the snapshot query engine for this store

Throws:

java.lang.UnsupportedOperationException - if the tag searching is not supported

tag

Tag tag(long revision)
        throws java.lang.Exception

Creates a tag for a snapshot of the server in a specific state at a revision. If the ChangeLog has a TaggableChangeLogStore then the tag is stored. If it does not then it's up to callers to track this tag since it will not be stored by this service.

Parameters:

revision - the revision to tag the snapshot

Returns:

the Tag associated with the revision

Throws:

java.lang.Exception - if there is a problem taking a tag

java.lang.IllegalArgumentException - if the revision is out of range (less than 0 and greater than the current revision)

tag

Tag tag(long revision,
        java.lang.String description)
        throws java.lang.Exception

Creates a tag for a snapshot of the server in a specific state at a revision. If the ChangeLog has a TaggableChangeLogStore then the tag is stored. If it does not then it's up to callers to track this tag since it will not be stored by this service.

Parameters:

revision - the revision to tag the snapshot

description - some information about what the snapshot tag represents

Returns:

the Tag associated with the revision

Throws:

java.lang.Exception - if there is a problem taking a tag

java.lang.IllegalArgumentException - if the revision is out of range (less than 0 and greater than the current revision)

tag

Tag tag(java.lang.String description)
        throws java.lang.Exception

Creates a snapshot of the server at the current revision.

Parameters:

description - some information about what the snapshot tag represents

Returns:

the revision at which the tag is created

Throws:

java.lang.Exception - if there is a problem taking a tag

tag

Tag tag()
        throws java.lang.Exception

Creates a snapshot of the server at the current revision.

Returns:

the revision at which the tag is created

Throws:

java.lang.Exception - if there is a problem taking a tag

getLatest

Tag getLatest()
              throws java.lang.Exception

Returns:

The latest tag

Throws:

java.lang.Exception - if there is a problem taking the latest tag

init

void init(DirectoryService service)
          throws java.lang.Exception

Initialize the ChangeLog system.

Parameters:

service - The associated DirectoryService

Throws:

java.lang.Exception

sync

void sync()
          throws java.lang.Exception

Flush the changes to disk

Throws:

java.lang.Exception - If the flush failed

destroy

void destroy()
             throws java.lang.Exception

Destroy the changeLog

Throws:

java.lang.Exception

setExposed

void setExposed(boolean exposed)

Exposes the contents of ChangeLog to clients if set to true. Default setting is false.

Parameters:

exposed - true to expose the contents, false to not expose.

isExposed

boolean isExposed()

Returns:

true if the changeLog system is visible by clients

setPartitionSuffix

void setPartitionSuffix(java.lang.String suffix)

The prefix of the partition. Default value is ou=changelog.

Parameters:

suffix - suffix value to be set for the changelog partition

setRevisionsContainerName

void setRevisionsContainerName(java.lang.String revContainerName)

The name of the revisions container under the partition. Default value is ou=revisions

Parameters:

revContainerName - the name of the revisions container

setTagsContainerName

void setTagsContainerName(java.lang.String tagContainerName)

The name of the tags container under the partition. Default value is ou=tags

Parameters:

tagContainerName - the name of the revisions container