org.neo4j.kernel.impl.proc.ProcedureRegistry Maven / Gradle / Ivy

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/*
 * Copyright (c) 2002-2016 "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 .
 */
package org.neo4j.kernel.impl.proc;

import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

import org.neo4j.collection.RawIterator;
import org.neo4j.kernel.api.exceptions.ProcedureException;
import org.neo4j.kernel.api.exceptions.Status;
import org.neo4j.kernel.api.proc.CallableProcedure;
import org.neo4j.kernel.api.proc.ProcedureSignature;

public class ProcedureRegistry
{
    private final Map procedures = new HashMap<>();

    /**
     * Register a new procedure. This method must not be called concurrently with {@link #get(ProcedureSignature.ProcedureName)}.
     *
     * @param proc the procedure.
     */
    public synchronized void register( CallableProcedure proc ) throws ProcedureException
    {
        ProcedureSignature signature = proc.signature();
        ProcedureSignature.ProcedureName name = signature.name();

        validateSignature( signature, signature.inputSignature(), "input" );
        validateSignature( signature, signature.outputSignature(), "output" );

        if ( procedures.putIfAbsent( name, proc ) != null )
        {
            throw new ProcedureException( Status.Procedure.FailedRegistration,
                    "Unable to register procedure, because the name `%s` is already in use.", name );
        }
    }

    private void validateSignature( ProcedureSignature signature, List fields, String fieldType )
            throws ProcedureException
    {
        Set names = new HashSet<>();
        for ( ProcedureSignature.FieldSignature field : fields )
        {
            if ( !names.add( field.name() ) )
            {
                throw new ProcedureException( Status.Procedure.FailedRegistration,
                        "Procedure `%s` cannot be registered, because it contains a duplicated " + fieldType + " field, '%s'. " +
                        "You need to rename or remove one of the duplicate fields.", signature.toString(), field.name() );
            }
        }
    }

    public ProcedureSignature get( ProcedureSignature.ProcedureName name ) throws ProcedureException
    {
        CallableProcedure proc = procedures.get( name );
        if ( proc == null )
        {
            throw noSuchProcedure( name );
        }
        return proc.signature();
    }

    public RawIterator call( CallableProcedure.Context ctx, ProcedureSignature.ProcedureName name, Object[] input )
            throws ProcedureException
    {
        CallableProcedure proc = procedures.get( name );
        if ( proc == null )
        {
            throw noSuchProcedure( name );
        }
        return proc.apply( ctx, input );
    }

    private ProcedureException noSuchProcedure( ProcedureSignature.ProcedureName name )
    {
        return new ProcedureException( Status.Procedure.NoSuchProcedure,
                "There is no procedure with the name `%s` registered for this database instance. " +
                "Please ensure you've spelled the procedure name correctly and that the " +
                "procedure is properly deployed.", name );
    }

    public Set getAll()
    {
        return procedures.values().stream().map( CallableProcedure::signature ).collect( Collectors.toSet());
    }
}