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/*
 * Copyright (c) 2018-2020 "Graph Foundation,"
 * Graph Foundation, Inc. [https://graphfoundation.org]
 *
 * This file is part of ONgDB.
 *
 * ONgDB 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 .
 */
/*
 * Copyright (c) 2002-2020 "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.kernel.spi.explicitindex;

import java.io.File;
import java.io.IOException;
import java.util.Map;

import org.neo4j.graphdb.ResourceIterator;
import org.neo4j.kernel.impl.api.TransactionApplier;
import org.neo4j.kernel.lifecycle.Lifecycle;

/**
 * An index provider which can create and give access to index transaction state and means of applying
 * updates to indexes it provides.
 * An {@link IndexImplementation} is typically tied to one implementation, f.ex.
 * lucene, http://lucene.apache.org/java.
 */
public interface IndexImplementation extends Lifecycle
{

    /**
     * Get index implementation root directory based on a store directory
     * @param storeDir store directory
     * @return index implementation root directory
     */
    File getIndexImplementationDirectory( File storeDir );

    /**
     * Returns a {@link ExplicitIndexProviderTransaction} that keeps transaction state for all
     * indexes for a given provider in a transaction.
     *
     * @param commandFactory index command factory to use
     * @return a {@link ExplicitIndexProviderTransaction} which represents a type of index suitable for the
     * given configuration.
     */
    ExplicitIndexProviderTransaction newTransaction( IndexCommandFactory commandFactory );

    /**
     * @param recovery indicate recovery
     * @return an index applier that will get notifications about commands to apply.
     */
    TransactionApplier newApplier( boolean recovery );

    /**
     * Fills in default configuration parameters for indexes provided from this
     * index provider. This method will also validate the the configuration is valid to be used
     * as index configuration for this provider.
     * @param config the configuration map to complete with defaults.
     * @return a {@link Map} filled with decent defaults for an index from
     * this index provider.
     */
    Map fillInDefaults( Map config );

    boolean configMatches( Map storedConfig, Map config );

    void force();

    /**
     * Lists store files that this index provider manages. After this call has been made and until
     * the returned {@link ResourceIterator} has been {@link ResourceIterator#close() closed} this
     * index provider must guarantee that the list of files stay intact. The files in the list can
     * change, but no files may be deleted or added during this period.
     * @return list of store files managed by this index provider
     * @throws IOException depends on the implementation
     */
    ResourceIterator listStoreFiles() throws IOException;
}