org.janusgraph.core

Interface JanusGraphTransaction

All Superinterfaces:

AutoCloseable, org.apache.tinkerpop.gremlin.structure.Graph, org.apache.tinkerpop.gremlin.structure.util.Host, SchemaInspector, SchemaManager, Transaction

All Known Implementing Classes:

JanusGraphBlueprintsTransaction, StandardJanusGraphTx

public interface JanusGraphTransaction
extends Transaction

JanusGraphTransaction defines a transactional context for a JanusGraph. Since JanusGraph is a transactional graph database, all interactions with the graph are mitigated by a JanusGraphTransaction.

All vertex and edge retrievals are channeled by a graph transaction which bundles all such retrievals, creations and deletions into one transaction. A graph transaction is analogous to a database transaction. The isolation level and ACID support are configured through the storage backend, meaning whatever level of isolation is supported by the storage backend is mirrored by a graph transaction.

A graph transaction supports:

• Creating vertices, properties and edges
• Creating types
• Index-based retrieval of vertices
• Querying edges and vertices
• Aborting and committing transaction

Author:

Matthias Bröcheler (http://www.matthiasb.com)

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.tinkerpop.gremlin.structure.Graph

org.apache.tinkerpop.gremlin.structure.Graph.Exceptions, org.apache.tinkerpop.gremlin.structure.Graph.Features, org.apache.tinkerpop.gremlin.structure.Graph.Hidden, org.apache.tinkerpop.gremlin.structure.Graph.OptIn, org.apache.tinkerpop.gremlin.structure.Graph.OptIns, org.apache.tinkerpop.gremlin.structure.Graph.OptOut, org.apache.tinkerpop.gremlin.structure.Graph.OptOuts, org.apache.tinkerpop.gremlin.structure.Graph.Variables

Field Summary

Fields inherited from interface org.apache.tinkerpop.gremlin.structure.Graph

GRAPH

Method Summary

Modifier and Type	Method and Description
JanusGraphVertex	addVertex(Long id, VertexLabel vertexLabel) Creates a new vertex in the graph with the given vertex id and the given vertex label.
void	commit() Commits and closes the transaction.
Iterable<JanusGraphEdge>	getEdges(RelationIdentifier... ids)
JanusGraphVertex	getVertex(long id) Retrieves the vertex for the specified id.
Iterable<JanusGraphVertex>	getVertices(long... ids)
boolean	hasModifications() Checks whether any changes to the graph database have been made in this transaction.
boolean	isClosed() Checks whether the transaction has been closed.
boolean	isOpen() Checks whether the transaction is still open.
void	rollback() Aborts and closes the transaction.

Methods inherited from interface org.janusgraph.core.Transaction

addVertex, addVertex, close, indexQuery, multiQuery, multiQuery, query

Methods inherited from interface org.apache.tinkerpop.gremlin.structure.Graph

compute, compute, configuration, edges, features, io, traversal, traversal, traversal, tx, variables, vertices

Methods inherited from interface org.janusgraph.core.schema.SchemaManager

makeEdgeLabel, makePropertyKey, makeVertexLabel

Methods inherited from interface org.janusgraph.core.schema.SchemaInspector

containsEdgeLabel, containsPropertyKey, containsRelationType, containsVertexLabel, getEdgeLabel, getOrCreateEdgeLabel, getOrCreatePropertyKey, getOrCreateVertexLabel, getPropertyKey, getRelationType, getVertexLabel

Method Detail

addVertex

JanusGraphVertex addVertex(Long id,
                           VertexLabel vertexLabel)

Creates a new vertex in the graph with the given vertex id and the given vertex label. Note, that an exception is thrown if the vertex id is not a valid JanusGraph vertex id or if a vertex with the given id already exists.

Custom id setting must be enabled via the configuration option GraphDatabaseConfiguration.ALLOW_SETTING_VERTEX_ID.

Use JanusGraphId.toVertexId(long) to construct a valid JanusGraph vertex id from a user id.

Parameters:

id - vertex id of the vertex to be created

vertexLabel - vertex label for this vertex - can be null if no vertex label should be set.

Returns:

New vertex

getVertex

JanusGraphVertex getVertex(long id)

Retrieves the vertex for the specified id. This method is intended for internal use only. Use Graph.vertices(Object...) instead.

Parameters:

id - id of the vertex to retrieve

Returns:

vertex with the given id if it exists, else null

getVertices

Iterable<JanusGraphVertex> getVertices(long... ids)

getEdges

Iterable<JanusGraphEdge> getEdges(RelationIdentifier... ids)

commit

void commit()

Commits and closes the transaction.

Will attempt to persist all modifications which may result in exceptions in case of persistence failures or lock contention.
The call releases data structures if possible. All element references (e.g. vertex objects) retrieved through this transaction are stale after the transaction closes and should no longer be used.

Throws:

BackendException - if an error arises during persistence

rollback

void rollback()

Aborts and closes the transaction. Will discard all modifications.

The call releases data structures if possible. All element references (e.g. vertex objects) retrieved through this transaction are stale after the transaction closes and should no longer be used.

Throws:

BackendException - if an error arises when releasing the transaction handle

isOpen

boolean isOpen()

Checks whether the transaction is still open.

Returns:

true, when the transaction is open, else false

isClosed

boolean isClosed()

Checks whether the transaction has been closed.

Returns:

true, if the transaction has been closed, else false

hasModifications

boolean hasModifications()

Checks whether any changes to the graph database have been made in this transaction.

A modification may be an edge or vertex update, addition, or deletion.

Returns:

true, if the transaction contains updates, else false.