org.flywaydb.core.api.migration.BaseJavaMigration Maven / Gradle / Ivy

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/*
 * Copyright (C) Red Gate Software Ltd 2010-2024
 *
 * 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
 *
 *         http://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 org.flywaydb.core.api.migration;

import org.flywaydb.core.api.CoreMigrationType;
import org.flywaydb.core.api.FlywayException;
import org.flywaydb.core.api.MigrationVersion;
import org.flywaydb.core.extensibility.MigrationType;
import org.flywaydb.core.internal.resolver.MigrationInfoHelper;
import org.flywaydb.core.internal.util.Pair;

/**
 * This is the recommended class to extend for implementing Java-based Migrations.
 * Subclasses should follow the default Flyway naming convention of having a class name with the following structure:
 * 
 * Versioned Migrations: V2__Add_new_table
 * Undo Migrations: U2__Add_new_table
 * Repeatable Migrations: R__Add_new_table
 * 
 *
 * The file name consists of the following parts:
 * 
 * Prefix: V for versioned migrations, U for undo migrations, R for repeatable migrations
 * Version: Underscores (automatically replaced by dots at runtime) separate as many parts as you like (Not for repeatable migrations)
 * Separator: __ (two underscores)
 * Description: Underscores (automatically replaced by spaces at runtime) separate the words
 * 
 * If you need more control over the class name, you can override the default convention by implementing the
 * JavaMigration interface directly. This will allow you to name your class as you wish. Version, description and
 * migration category are provided by implementing the respective methods.
 */
public abstract class BaseJavaMigration implements JavaMigration {
    private MigrationVersion version;
    private String description;

    /**
     * Creates a new instance of a Java-based migration following Flyway's default naming convention.
     */
    public BaseJavaMigration() {
        init();
    }

    protected void init() {
        String shortName = getClass().getSimpleName();
        String prefix = null;

        boolean repeatable = shortName.startsWith("R");

        if (shortName.startsWith("V") || repeatable) {
            prefix = shortName.substring(0, 1);
        }
        if (prefix == null) {
            throw new FlywayException("Invalid Java-based migration class name: " + getClass().getName() +
                                              " => ensure it starts with V or R" +
                                              " or implement org.flywaydb.core.api.migration.JavaMigration directly for non-default naming");
        }
        extractVersionAndDescription(shortName, prefix, repeatable);
    }

    protected void extractVersionAndDescription(String shortName, String prefix, boolean repeatable) {
        Pair info = MigrationInfoHelper.extractVersionAndDescription(shortName, prefix, "__", new String[] {""}, repeatable);
        version = info.getLeft();
        description = info.getRight();
    }

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

    @Override
    public String getDescription() {
        return description;
    }

    @Override
    public Integer getChecksum() {
        return null;
    }

    @Override
    public boolean canExecuteInTransaction() {
        return true;
    }
}