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Colesico framework unified transactions control support for service beans
There is a newer version: 5.3.0
/*
 * Copyright © 2014-2020 Vladlen V. Larionov and others as noted.
 *
 * 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 colesico.framework.transaction;

import org.slf4j.Logger;

/**
 * Abstract common transactional shell functionality
 *
 * @param  transaction type
 * @param  tuning type
 */
abstract public class AbstractTransactionalShell implements TransactionalShell {

    protected final Logger logger;

    protected final ThreadLocal transactions = new ThreadLocal<>();

    public AbstractTransactionalShell(Logger logger) {
        this.logger = logger;
    }

    abstract protected  R createNew(UnitOfWork unitOfWork, U tuning);

    @Override
    public  R required(UnitOfWork unitOfWork, U tuning) {
        logger.debug("TX-Required begin");
        T tx = transactions.get();
        R result;
        if (tx == null) {
            result = createNew(unitOfWork, tuning);
        } else {
            result = unitOfWork.execute();
        }
        logger.debug("TX-Required end");
        return result;
    }

    @Override
    public  R requiresNew(UnitOfWork unitOfWork, U tuning) {
        logger.debug("TX-RequiresNew begin");
        T tx = transactions.get();
        if (tx == null) {
            R result = createNew(unitOfWork, tuning);
            logger.debug("TX-RequiresNew end");
            return result;
        } else {
            try {
                transactions.remove();
                return createNew(unitOfWork, tuning);
            } finally {
                transactions.set(tx);
                logger.debug("TX-RequiresNew end");
            }
        }
    }

    @Override
    public  R mandatory(UnitOfWork unitOfWork, U tuning) {
        logger.debug("TX-Mandatory begin");
        getTransaction();
        R result = unitOfWork.execute();
        logger.debug("TX-Mandatory end");
        return result;
    }

    @Override
    public  R notSupported(UnitOfWork unitOfWork, U tuning) {
        logger.debug("TX-NotSupported begin");
        T tx = transactions.get();
        if (tx == null) {
            R result = unitOfWork.execute();
            logger.debug("TX-NotSupported end");
            return result;
        } else {
            try {
                transactions.remove();
                return unitOfWork.execute();
            } finally {
                transactions.set(tx);
                logger.debug("TX-NotSupported end");
            }
        }
    }

    @Override
    public  R supports(UnitOfWork unitOfWork, U tuning) {
        logger.debug("TX-Supports begin");
        R result = unitOfWork.execute();
        logger.debug("TX-Supports end");
        return result;
    }

    @Override
    public  R never(UnitOfWork unitOfWork, U tuning) {
        logger.debug("TX-Never begin");
        T tx = transactions.get();
        if (tx != null) {
            logger.debug("TX-Never ned");
            throw new IllegalStateException("Active transaction exists");
        }
        logger.debug("TX-Never ned");
        return unitOfWork.execute();
    }

    @Override
    public  R nested(UnitOfWork unitOfWork, U tuning) {
        //For jdbc based transactions this can be implemented with savepoints (see jooq as example)
        throw new UnsupportedOperationException("Nested transactions is not supported.");
    }

    /**
     * Returns active transaction, trown exception otherwise
     *
     * @return
     */
    public T getTransaction() {
        T tx = transactions.get();
        if (tx == null) {
            throw new IllegalStateException("No active transaction");
        }
        return tx;
    }

    /**
     * Returns active transaction or null
     *
     * @return
     */
    public T getTransactionOrNull() {
        return transactions.get();
    }


    /**
     * Cast a CheckedException as an unchecked one.
     *
     * @param throwable to cast
     * @param        the type of the Throwable
     * @return this method will never return a Throwable instance, it will just throw it.
     * @throws T the throwable as an unchecked throwable
     */
    @SuppressWarnings("unchecked")
    public static  RuntimeException rethrow(Throwable throwable) throws T {
        throw (T) throwable; // rely on vacuous cast
    }
}