/**
* Copyright (c) 2002-2013 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.graphdb;
import org.neo4j.graphdb.event.KernelEventHandler;
import org.neo4j.graphdb.event.TransactionEventHandler;
import org.neo4j.graphdb.index.IndexManager;
import org.neo4j.kernel.EmbeddedGraphDatabase;
/**
* The main access point to a running Neo4j instance. The most common
* implementation is the {@link EmbeddedGraphDatabase} class, which is used to
* embed Neo4j in an application. Typically, you would create an
* <code>EmbeddedGraphDatabase</code> instance as follows:
*
* <pre>
* <code>GraphDatabaseService graphDb = new EmbeddedGraphDatabase( "var/graphDb" );
* // ... use Neo4j
* graphDb.{@link #shutdown() shutdown()};</code>
* </pre>
*
* GraphDatabaseService provides operations to {@link #createNode() create
* nodes}, {@link #getNodeById(long) get nodes given an id}, get the
* {@link #getReferenceNode() reference node} and ultimately {@link #shutdown()
* shutdown Neo4j}.
* <p>
* Please note that all operations that write to the graph must be invoked in a
* {@link Transaction transactional context}. Failure to do so will result in a
* {@link NotInTransactionException} being thrown.
*/
public interface GraphDatabaseService
{
/**
* Creates a new node.
*
* @return the created node.
*/
public Node createNode();
/**
* Looks up a node by id.
*
* @param id the id of the node
* @return the node with id <code>id</code> if found
* @throws NotFoundException if not found
*/
public Node getNodeById( long id );
/**
* Looks up a relationship by id.
*
* @param id the id of the relationship
* @return the relationship with id <code>id</code> if found
* @throws NotFoundException if not found
*/
public Relationship getRelationshipById( long id );
/**
* Returns the reference node, which is a "starting point" in the node
* space. Usually, a client attaches relationships to this node that leads
* into various parts of the node space. For more information about common
* node space organizational patterns, see the design guide at <a
* href="http://wiki.neo4j.org/content/Design_Guide"
* >wiki.neo4j.org/content/Design_Guide</a>.
*
* @return the reference node
* @throws NotFoundException if unable to get the reference node
*/
public Node getReferenceNode();
/**
* Returns all nodes in the node space.
*
* @return all nodes in the node space
*/
public Iterable<Node> getAllNodes();
/**
* Returns all relationship types currently in the underlying store.
* Relationship types are added to the underlying store the first time they
* are used in a successfully commited {@link Node#createRelationshipTo
* node.createRelationshipTo(...)}. Note that this method is guaranteed to
* return all known relationship types, but it does not guarantee that it
* won't return <i>more</i> than that (e.g. it can return "historic"
* relationship types that no longer have any relationships in the node
* space).
*
* @return all relationship types in the underlying store
*/
public Iterable<RelationshipType> getRelationshipTypes();
/**
* Shuts down Neo4j. After this method has been invoked, it's invalid to
* invoke any methods in the Neo4j API and all references to this instance
* of GraphDatabaseService should be discarded.
*/
public void shutdown();
/**
* Starts a new transaction and associates it with the current thread.
*
* @return a new transaction instance
*/
public Transaction beginTx();
/**
* Registers {@code handler} as a handler for transaction events which
* are generated from different places in the lifecycle of each
* transaction. To guarantee that the handler gets all events properly
* it shouldn't be registered when the application is running (i.e. in the
* middle of one or more transactions). If the specified handler instance
* has already been registered this method will do nothing.
*
* @param <T> the type of state object used in the handler, see more
* documentation about it at {@link TransactionEventHandler}.
* @param handler the handler to receive events about different states
* in transaction lifecycles.
* @return the handler passed in as the argument.
*/
public <T> TransactionEventHandler<T> registerTransactionEventHandler(
TransactionEventHandler<T> handler );
/**
* Unregisters {@code handler} from the list of transaction event handlers.
* If {@code handler} hasn't been registered with
* {@link #registerTransactionEventHandler(TransactionEventHandler)} prior
* to calling this method an {@link IllegalStateException} will be thrown.
* After a successful call to this method the {@code handler} will no
* longer receive any transaction events.
*
* @param <T> the type of state object used in the handler, see more
* documentation about it at {@link TransactionEventHandler}.
* @param handler the handler to receive events about different states
* in transaction lifecycles.
* @return the handler passed in as the argument.
* @throws IllegalStateException if {@code handler} wasn't registered prior
* to calling this method.
*/
public <T> TransactionEventHandler<T> unregisterTransactionEventHandler(
TransactionEventHandler<T> handler );
/**
* Registers {@code handler} as a handler for kernel events which
* are generated from different places in the lifecycle of the kernel.
* To guarantee proper behaviour the handler should be registered right
* after the graph database has been started. If the specified handler
* instance has already been registered this method will do nothing.
*
* @param handler the handler to receive events about different states
* in the kernel lifecycle.
* @return the handler passed in as the argument.
*/
public KernelEventHandler registerKernelEventHandler(
KernelEventHandler handler );
/**
* Unregisters {@code handler} from the list of kernel event handlers.
* If {@code handler} hasn't been registered with
* {@link #registerKernelEventHandler(KernelEventHandler)} prior to calling
* this method an {@link IllegalStateException} will be thrown.
* After a successful call to this method the {@code handler} will no
* longer receive any kernel events.
*
* @param handler the handler to receive events about different states
* in the kernel lifecycle.
* @return the handler passed in as the argument.
* @throws IllegalStateException if {@code handler} wasn't registered prior
* to calling this method.
*/
public KernelEventHandler unregisterKernelEventHandler(
KernelEventHandler handler );
/**
* Returns the {@link IndexManager} paired with this graph database service
* and is the entry point for managing indexes coupled with this database.
* @return the {@link IndexManager} for this database.
*/
public IndexManager index();
}