TransactionManager.java

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package org.apache.cayenne.tx;

/**
 * An optional utility service that simplifies wrapping multiple operations in
 * transactions. Users only rarely need to invoke it directly, as all standard
 * Cayenne operations are managing their own transactions internally.
 *
 * @since 4.0
 */
public interface TransactionManager {

    /**
     * Starts a new transaction (or joins an existing one) calling
     * {@link org.apache.cayenne.tx.TransactionalOperation#perform()}, and then committing or rolling back the
     * transaction.
     *
     * @param op an operation to perform within the trsnaction.
     * @return a value returned by the "op" operation.
     */
    <T> T performInTransaction(TransactionalOperation<T> op);

    /**
     * Starts a new transaction (or joins an existing one) calling
     * {@link org.apache.cayenne.tx.TransactionalOperation#perform()}, and then committing or rolling back the
     * transaction. As transaction goes through stages, callback methods are invoked allowing the caller to customize
     * transaction parameters.
     *
     * @param op       an operation to perform within the trsnaction.
     * @param callback a callback to notify as transaction progresses through stages.
     * @return a value returned by the "op" operation.
     */
    <T> T performInTransaction(TransactionalOperation<T> op, TransactionListener callback);
}