/*
* Hibernate OGM, Domain model persistence for NoSQL datastores
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.ogm.datastore.neo4j.remote.bolt.dialect.impl;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.hibernate.boot.model.relational.Sequence;
import org.hibernate.ogm.datastore.neo4j.dialect.impl.NodeLabel;
import org.hibernate.ogm.datastore.neo4j.dialect.impl.RemoteNeo4jSequenceGenerator;
import org.hibernate.ogm.datastore.neo4j.logging.impl.Log;
import org.hibernate.ogm.datastore.neo4j.logging.impl.LoggerFactory;
import org.hibernate.ogm.datastore.neo4j.remote.bolt.impl.BoltNeo4jClient;
import org.hibernate.ogm.datastore.neo4j.remote.common.request.impl.RemoteStatement;
import org.hibernate.ogm.datastore.neo4j.remote.common.request.impl.RemoteStatements;
import org.hibernate.ogm.id.impl.OgmSequenceGenerator;
import org.hibernate.ogm.id.impl.OgmTableGenerator;
import org.hibernate.ogm.model.key.spi.IdSourceKey;
import org.hibernate.ogm.model.key.spi.IdSourceKeyMetadata;
import org.hibernate.ogm.model.key.spi.IdSourceKeyMetadata.IdSourceType;
import org.neo4j.driver.v1.Driver;
import org.neo4j.driver.v1.Session;
import org.neo4j.driver.v1.Statement;
import org.neo4j.driver.v1.StatementResult;
import org.neo4j.driver.v1.Transaction;
import org.neo4j.driver.v1.util.Resource;
/**
* Generates the next value of an id sequence as represented by {@link IdSourceKey}.
* <p>
* Both, {@link IdSourceType#TABLE} and {@link IdSourceType#SEQUENCE} are supported. For the table strategy, nodes in
* the following form are used (the exact property names and the label value can be configured using the options exposed
* by {@link OgmTableGenerator}):
*
* <pre>
* (:hibernate_sequences:TABLE_BASED_SEQUENCE { sequence_name = 'ExampleSequence', current_value : 3 })
* </pre>
*
* For the sequence strategy, nodes in the following form are used (the sequence name can be configured using the option
* exposed by {@link OgmSequenceGenerator}):
*
* <pre>
* (:SEQUENCE { sequence_name = 'ExampleSequence', next_val : 3 })
* </pre>
*
* Sequences are created at startup.
* <p>
* A write lock is acquired on the node every time the sequence needs to be updated.
*
* @author Davide D'Alto <davide@hibernate.org>
* @author Gunnar Morling
*/
public class BoltNeo4jSequenceGenerator extends RemoteNeo4jSequenceGenerator {
private static final Log logger = LoggerFactory.getLogger();
private final BoltNeo4jClient client;
public BoltNeo4jSequenceGenerator(BoltNeo4jClient client, int sequenceCacheMaxSize) {
super( sequenceCacheMaxSize );
this.client = client;
}
/**
* Create the sequence nodes setting the initial value if the node does not exist already.
* <p>
* All nodes are created inside the same transaction.
*/
private void createSequencesConstraintsStatements(List<Statement> statements, Iterable<Sequence> sequences) {
Statement statement = createUniqueConstraintStatement( SEQUENCE_NAME_PROPERTY, NodeLabel.SEQUENCE.name() );
statements.add( statement );
}
/**
* Adds a node for each generator of type {@link IdSourceType#SEQUENCE}. Table-based generators are created lazily
* at runtime.
*
* @param sequences the generators to process
*/
public List<Statement> createSequencesStatements(Iterable<Sequence> sequences) {
List<Statement> statements = new ArrayList<Statement>();
for ( Sequence sequence : sequences ) {
addSequence( statements, sequence );
}
return statements;
}
/**
* Adds a unique constraint to make sure that each node of the same "sequence table" is unique.
*/
private void addUniqueConstraintForTableBasedSequence(List<Statement> statements, IdSourceKeyMetadata generatorKeyMetadata) {
Statement statement = createUniqueConstraintStatement( generatorKeyMetadata.getKeyColumnName(), generatorKeyMetadata.getName() );
statements.add( statement );
}
private Statement createUniqueConstraintStatement(String propertyName, String label) {
String queryString = createUniqueConstraintQuery( propertyName, label );
Statement statement = new Statement( queryString );
return statement;
}
private void addSequence(List<Statement> statements, Sequence sequence) {
Statement statement = new Statement( SEQUENCE_CREATION_QUERY, Collections.<String, Object>singletonMap( SEQUENCE_NAME_QUERY_PARAM, sequence.getName().render() ) );
statements.add( statement );
}
/**
* Generate the next value in a sequence for a given {@link IdSourceKey}.
*
* @return the next value in a sequence
*/
@Override
protected Number nextValue(RemoteStatements remoteStatements) {
List<Statement> statements = convert( remoteStatements );
StatementResult result = execute( statements );
Number nextValue = result.single().get( 0 ).asNumber();
return nextValue;
}
public void createUniqueConstraintsForTableSequences(List<Statement> statements, Iterable<IdSourceKeyMetadata> tableIdGenerators) {
for ( IdSourceKeyMetadata idSourceKeyMetadata : tableIdGenerators ) {
if ( idSourceKeyMetadata.getType() == IdSourceType.TABLE ) {
addUniqueConstraintForTableBasedSequence( statements, idSourceKeyMetadata );
}
}
}
private List<Statement> convert(RemoteStatements remoteStatements) {
List<Statement> statements = new ArrayList<>();
for ( RemoteStatement remoteStatement : remoteStatements ) {
Statement statement = new Statement( remoteStatement.getQuery(), remoteStatement.getParams() );
statements.add( statement );
}
return statements;
}
private void createUniqueConstraints(List<Sequence> sequences, Iterable<IdSourceKeyMetadata> idSourceKeyMetadata) {
List<Statement> statements = new ArrayList<Statement>();
createSequencesConstraintsStatements( statements, sequences );
createUniqueConstraintsForTableSequences( statements, idSourceKeyMetadata );
execute( statements );
}
@Override
public void createSequences(List<Sequence> sequences, Iterable<IdSourceKeyMetadata> idSourceKeyMetadata) {
createUniqueConstraints( sequences, idSourceKeyMetadata );
List<Statement> statements = createSequencesStatements( sequences );
execute( statements );
}
private StatementResult execute( List<Statement> statements ) {
Driver driver = client.getDriver();
Session session = null;
try {
session = driver.session();
Transaction tx = null;
try {
tx = session.beginTransaction();
StatementResult result = runAll( tx, statements );
tx.success();
return result;
}
finally {
close( tx );
}
}
finally {
close( session );
}
}
private StatementResult runAll(Transaction tx, List<Statement> statements) {
StatementResult result = null;
for ( Statement statement : statements ) {
result = tx.run( statement );
validate( result );
}
return result;
}
private void validate(StatementResult result) {
result.hasNext();
}
private void close(Resource closable) {
if ( closable != null ) {
closable.close();
}
}
}