Blueprints 2 introduced numerous changes to the Blueprints API. This page helps to explain these differences so updating code from Blueprints 1.x to Blueprints 2.x is as easy as possible.
In the early days of Blueprints, there were two notions:
To account for these two models, there were two packages:
com.tinkerpop.blueprints.odm. Blueprints has since focused solely on the property graph model and as such, in Blueprints 2.x, there is no more
pgm, it is simply
There is no more notion of
AutomaticIndex in Blueprints 2. Many graph databases such as
TitanGraph do not support the notion of arbitrary indexing. Instead, they simply allow an element to be indexed by its key/value property pairs. As such,
KeyIndexableGraph provides an interface to this basic indexing functionality (see Graph Indices). To index the
name key of all vertices, simply do:
graph.getVertices("name", "stephen") is evaluated, the
name index is used. If no such key index was created, then a linear scan of all the vertices in the graph would occur. Thus, be sure to add the appropriate indices to make an
For “manual indexing,” there is still the notion of
IndexableGraph and the
Index class. This is used by graph engines like
Since automatic indices in Blueprints 1.x are now just normal indices in Blueprints 2.x, it is relatively easy to convert them as follows:
graph.createKeyIndex() is executed, it will automatically re-index the graph. The amount of time taken to complete this re-indexing is dependent upon the size of the graph and what is being indexed. As an added step for safety, be sure to back up the Neo4j directory prior to re-indexing.
In Blueprints 1.x, there existed the following
Vertex.getOutEdges(String... labels) Vertex.getInEdges(String... labels)
As of Blueprints 2.x, there are now the following
Vertex.getEdges(Direction direction, String... labels) Vertex.getVertices(Direction direction, String... labels)
Vertex.getEdges(), it is possible to get the incoming, outgoing, or both incident edges to a vertex filtered by their edge label. With
Vertex.getVertices(), it is possible to get the incoming, outgoing, or both adjacent vertices to a vertex filtered by the edge label of the adjoining edges. Likewise, in a similar fashion,
Edge has been updated with the following method.
There is a new method in the
Vertex class called
Vertex.query(). This method returns a
Query object that has a fluent interface. The
Query object is a way of intelligently selecting adjacent vertices or incident edges to a vertex. Please learn more about
Query on the Vertex Query wiki page.
In Blueprints 1.x,
TransactionalGraph had the following methods.
TransactionalGraph.setMaxBufferSize(long size) TransactionalGraph.getMaxBufferSize(); TransactionalGraph.getCurrentBufferSize()
These methods were used to automatically commits “chunks” of data. Those chunks were the size of the buffer. This functionality was deemed too specific a use case and should not be mixed in with
TransactionalGraph. As such, this behavior has now been relegated to
BatchGraph (see Batch Implementation).
TransactionalGraph each transaction is bound to an executing thread and a transaction is automatically started with the first operation on the graph (read or write). Hence,
TransactionalGraph.startTransaction() is not needed and has been removed. The user only needs to mark the end of a transaction by calling
To allow multiple threads to execute in one transaction, which is useful when implementing parallelized graph algorithms, the
ThreadedTransactionalGraph interface has been added. It’s
startTransaction() method returns a
TransactionalGraph object which represents a single transaction and can be accessed concurrently from multiple threads.
NOTE: Since Blueprints 2.3.0
stopTransaction(Conclusion) has been deprecated in favor of
rollback(). Same semantics as
FAILURE, but less typing for the developer.
There are two types of “wrapping” Blueprints implementations.
WrapperGraph: The underlying graph is a Blueprints
MetaGraph: The underlying graph is a vendor specific API.
Blueprints provides numerous
WrapperGraph implementations that allow users add-on functionality to their graph. Examples include
BatchGraph, etc. Next, most vendors make use of
MetaGraph where their Blueprints implementation wraps their native API. Thus, there are two methods to be aware of in these respective interfaces.
T extends Graph WrapperGraph.getBaseGraph() // can recursively go down if T is a WrapperGraph T MetaGraph.getRawGraph() // returns the raw vendor specific graph object