org.apache.directory.server.core.api.changelog

Interface TagSearchEngine

public interface TagSearchEngine

An optional search interface supported by TaggableChangeLogStores. This interface enables the:

• lookup of tags by revision
• finding all tags
• finding tags before or after a revision
• finding tags in some revision range

While investigating these interface methods keep in mind that only one tag can exist on a revision. Unlike subversion which allows multiple tags on a revision we only allow at most one: more than one is pointless. Date wise searches for tags are not present within this interface since they should be used in conjunction with the ChangeLogSearchEngine which is by default supported by TaggableSearchableChangeLogStores. The ChangeLogSearchEngine can find revisions based on time descriptors and returned revisions can be checked for the presence of tags using this interface. The whole point to enabling both search engines in a single interfaces is because if you can search for tags you should be able to search for revisions: however the converse may not be the case.

Author:

Apache Directory Project

Method Summary

Modifier and Type	Method and Description
org.apache.directory.api.ldap.model.cursor.Cursor<Tag>	find(long startRevision, long endRevision, RevisionOrder order) Enumerates over the tags of all snapshots taken between a specific revision range inclusive.
org.apache.directory.api.ldap.model.cursor.Cursor<Tag>	find(RevisionOrder order) Finds all the snapshot tags taken since revision 0 until the current revision.
org.apache.directory.api.ldap.model.cursor.Cursor<Tag>	findAfter(long revision, RevisionOrder order) Finds all the snapshot tags taken after a specific revision.
org.apache.directory.api.ldap.model.cursor.Cursor<Tag>	findBefore(long revision, RevisionOrder order) Finds all the snapshot tags taken before a specific revision.
boolean	has(long revision) Checks to see if a snapshot exists for a specific revision.
Tag	lookup(long revision) Gets the tag for a specific snapshot if that snapshot exists.

Method Detail

lookup

Tag lookup(long revision)
    throws Exception

Gets the tag for a specific snapshot if that snapshot exists.

Parameters:

revision - the revision number to use to check for a snapshot

Returns:

the snapshot at the revision if one exists, otherwise null

Throws:

Exception - if there is a problem accessing the store

has

boolean has(long revision)
     throws Exception

Checks to see if a snapshot exists for a specific revision.

Parameters:

revision - the revision number to use to check for a snapshot

Returns:

true if a snapshot exists at the revision, false otherwise

Throws:

Exception - if there is a problem accessing the store

find

org.apache.directory.api.ldap.model.cursor.Cursor<Tag> find(RevisionOrder order)
                                                     throws Exception

Finds all the snapshot tags taken since revision 0 until the current revision.

Parameters:

order - the revision order in which to return snapshot tags

Returns:

a cursor containing the tags of all snapshots taken since revision 1

Throws:

Exception - if there is a problem accessing the store

findBefore

org.apache.directory.api.ldap.model.cursor.Cursor<Tag> findBefore(long revision,
                                                                  RevisionOrder order)
                                                           throws Exception

Finds all the snapshot tags taken before a specific revision. If a tag exists at the revision parameter it will be returned as well.

Parameters:

revision - the revision number to get snapshots before

order - the revision order in which to return snapshot tags

Returns:

an enumeration over the tags of all snapshots taken before a revision inclusive

Throws:

Exception - if there is a problem accessing the store

IllegalArgumentException - if the revision is greater than the current revision or less than 0.

findAfter

org.apache.directory.api.ldap.model.cursor.Cursor<Tag> findAfter(long revision,
                                                                 RevisionOrder order)
                                                          throws Exception

Finds all the snapshot tags taken after a specific revision. If a tag exists at the revision parameter it will be returned as well.

Parameters:

revision - the revision number to get snapshots after

order - the revision order in which to return snapshot tags

Returns:

an enumeration over the tags of all snapshots taken after a revision inclusive

Throws:

Exception - if there is a problem accessing the store

IllegalArgumentException - if the revision is greater than the current revision or less than 0.

find

org.apache.directory.api.ldap.model.cursor.Cursor<Tag> find(long startRevision,
                                                            long endRevision,
                                                            RevisionOrder order)
                                                     throws Exception

Enumerates over the tags of all snapshots taken between a specific revision range inclusive. The first revision parameter should be less than or equal to the second revision parameter.

Parameters:

startRevision - the revision to start on inclusive

endRevision - the revision to end on inclusive

order - the revision order in which to return snapshot tags

Returns:

enumeration over all the snapshots taken in a revision range inclusive

Throws:

Exception - if there is a problem accessing the store

IllegalArgumentException - if the revision range is not constructed properly or if either revision number is greater than the current revision or less than 0.