com.wizarius.orm.migrations.savers.DBFileMigrationSaver Maven / Gradle / Ivy

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package com.wizarius.orm.migrations.savers;

import com.wizarius.orm.migrations.DBMigrationException;
import com.wizarius.orm.migrations.entities.DBMigrationEntity;
import com.wizarius.orm.migrations.entities.DBMigrationEntityList;
import com.wizarius.orm.utils.WizariusJsonUtils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

/**
 * Created by Vladyslav Shyshkin on 24.11.2017.
 */
public class DBFileMigrationSaver implements IMigrationSaver {
    private final String path;

    /**
     * DB Json migration saver
     *
     * @param path path to dump file
     */
    public DBFileMigrationSaver(String path) throws DBMigrationException {
        this.path = path;
        if (!isCorrectName()) {
            throw new DBMigrationException("Wrong filename");
        }
        if (!isDumpFileExist()) {
            createEmptyFile(path);
        }
    }

    /**
     * Save migration
     *
     * @param migration migration
     * @throws DBMigrationException on unable to save
     */
    @Override
    public void save(DBMigrationEntity migration) throws DBMigrationException {
        DBMigrationEntityList migrations = read();
        if (migrations.getByLevels(migration.getLevel()) == null) {
            migrations.add(migration);
            try (FileOutputStream fos = new FileOutputStream(new File(path))) {
                String json = WizariusJsonUtils.toPrettyJson(migrations);
                if (json == null) {
                    throw new DBMigrationException("Unable to convert migrations to json");
                }
                fos.write(json.getBytes());
            } catch (IOException e) {
                throw new DBMigrationException("Unable to save to file " + e.getMessage(), e);
            }
        }
    }

    /**
     * Read from dump file
     *
     * @return connection migrations list
     * @throws DBMigrationException on unable to read froom file
     */
    @Override
    public DBMigrationEntityList read() throws DBMigrationException {
        File file = new File(path);
        try (FileInputStream fos = new FileInputStream(file)) {
            byte[] result = new byte[(int) file.length()];
            int read = fos.read(result);
            String json = new String(result, StandardCharsets.UTF_8);
            if (read != -1 && json.length() != 0) {
                return WizariusJsonUtils.fromJson(json, DBMigrationEntityList.class);
            } else {
                return new DBMigrationEntityList();
            }
        } catch (IOException e) {
            throw new DBMigrationException("Unable to save to file " + e.getMessage(), e);
        }
    }

    /**
     * Check if file is exist
     *
     * @return true if file exist
     */
    private boolean isDumpFileExist() {
        File file = new File(path);
        return file.exists() && file.isFile();
    }

    /**
     * Create new empty file
     *
     * @param path path to file
     */
    private void createEmptyFile(String path) throws DBMigrationException {
        File file = new File(path);
        try {
            if (!file.createNewFile()) {
                throw new DBMigrationException("Unable to create connection migration file by path " + path);
            }
        } catch (IOException e) {
            throw new DBMigrationException("Unable to create connection migration file " + e.getMessage());
        }
    }

    /**
     * Check if file is correct
     *
     * @return true if file exist
     */
    private boolean isCorrectName() {
        return path.endsWith("wizariusDBMigration");
    }
}