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The Core API of Neo4j-Migrations.
There is a newer version: 2.15.1
/*
 * Copyright 2020-2022 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package ac.simons.neo4j.migrations.core;

import java.util.Optional;
import java.util.function.UnaryOperator;

/**
 * This is a utility class for every {@link Migration} that wants to provide Cypher to Neo4j-Migrations (via an extension).
 * For example this can be a format extension extracting Cypher from various text formats. This base class uses a
 * {@link CypherResource} under the hood taking care of checksuming Cypher etc.
 *
 * @author Michael J. Simons
 * @soundtrack Koljah - Aber der Abgrund
 * @since 1.8.0
 */
public abstract class AbstractCypherBasedMigration implements Migration {

	protected final CypherResource cypherResource;
	/**
	 * @deprecated since 1.9.0, see {@link #getOptionalDescription()}
	 */
	@Deprecated
	protected final String description;
	protected final MigrationVersion version;

	@SuppressWarnings("squid:S1874") // Assignment to description
	protected AbstractCypherBasedMigration(CypherResource cypherResource) {
		this.cypherResource = cypherResource;
		this.version = MigrationVersion.parse(this.cypherResource.getIdentifier());
		this.description = this.version.getOptionalDescription().orElse(null);
	}

	@Override
	public final MigrationVersion getVersion() {
		return version;
	}

	@Override
	@SuppressWarnings("deprecation")
	public final String getDescription() {
		return version.getOptionalDescription().orElse(null);
	}

	@Override
	public Optional getOptionalDescription() {
		return version.getOptionalDescription();
	}

	/**
	 * This can be overridden to provide a better identifier for this source (for example an anchor in an adoc file).
	 * The {@link CypherResource cypher resource} itself must have an identifier that can be parsed into a {@link MigrationVersion}.
	 *
	 * @return An identifier for this migration.
	 */
	@Override
	public String getSource() {
		return this.cypherResource.getIdentifier();
	}

	@Override
	public final Optional getChecksum() {
		return Optional.of(cypherResource.getChecksum());
	}

	@Override
	public final void apply(MigrationContext context) throws MigrationsException {
		DefaultCypherResource.executeIn(cypherResource, context, UnaryOperator.identity());
	}
}