Implementations
In order to connect a graph database to Blueprints, the Blueprints property graph interfaces must be implemented. For non-native Blueprints graph databases, the raw graph database API and the Blueprints API need to be coupled. For native Blueprints graph databases, no such coupling is needed as only the interfaces need to be implemented. Each subsection discusses the various implementations of the Blueprints interfaces maintained by the main Blueprints distribution.
DEPENDENCY NOTE: It is important to note that including a <dependency/> to Blueprints does not entail all the respective graph database/framework dependencies distributed with Blueprints. The reason for this is that it allows users to include only those graph implementations they wish for their particular projects (e.g. based on licensing, size, performance, etc.).
This section defines the general rules and standards by which Blueprints implementations are expected to work. By following these implementation details, developers implementing the Blueprints API can expect consistent operations throughout the TinkerPop stack. Many of these details are enforced by the Blueprints test suite, so there will be little choice in those areas when it comes to implementation, however others are merely convention and not explicitly enforced. Choosing not to following convention will introduce risk that the implementation will not work as expected elsewhere in the stack.
The getVertex and getEdge methods on the Graph class accept an object type as the parameter for the respective vertex or edge identifier. Always coerce that identifier to its expected type. If the underlying graph, only expects a long as an identifier, then ensure that the parameter is converted to a long (as it may come in as a String or other such value). If the identifier cannot be coerced to its expected type then simply return null.
The identifier parameter cannot be null and if it is an exception should immediately be thrown:
if (null == id)
throw ExceptionFactory.vertexIdCanNotBeNull();