org.neo4j.capabilities.CapabilityProviderDependencies Maven / Gradle / Ivy

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/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.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.capabilities;

import java.util.HashMap;
import java.util.Map;
import java.util.function.Supplier;

import org.neo4j.exceptions.UnsatisfiedDependencyException;

final class CapabilityProviderDependencies
{
    private final Map,Supplier> dependencies;

    CapabilityProviderDependencies()
    {
        this.dependencies = new HashMap<>();
    }

     void register( Class cls, Supplier supplier )
    {
        var old = dependencies.putIfAbsent( cls, supplier );
        if ( old != null )
        {
            throw new UnsupportedOperationException( String.format( "'%s' is already registered.", cls.getName() ) );
        }
    }

    @SuppressWarnings( "unchecked" )
     T get( Class cls )
    {
        var supplier = this.dependencies.get( cls );
        if ( supplier == null )
        {
            throw new UnsatisfiedDependencyException( cls );
        }

        return (T) supplier.get();
    }
}