/// <summary>
/// Initializes a new instance of the <see cref="Transaction"/> class.
/// </summary>
///
/// <param name="session">The parent session that represents the communication channel to QLDB.</param>
/// <param name="txnId">Transaction identifier.</param>
/// <param name="logger">Logger to be used by this.</param>
internal Transaction(Session session, string txnId, ILogger logger)
{
this.session = session;
this.txnId = txnId;
this.logger = logger;
this.qldbHash = QldbHash.ToQldbHash(txnId);
}
/// <summary>
/// Calculates the QLDB hash.
/// </summary>
///
/// <param name="that">Hashed PartiQL statement.</param>
///
/// <returns>QldbHash.</returns>
internal QldbHash Dot(QldbHash that)
{
byte[] concatenated = JoinHashesPairwise(this.Hash, that.Hash);
HashAlgorithm hashAlgorithm = HashAlgorithm.Create("SHA256");
return(new QldbHash(hashAlgorithm.ComputeHash(concatenated)));
}
/// <summary>
/// Calculate the QLDB hash from statement and parameters.
/// </summary>
///
/// <param name="seed">QLDB Hash.</param>
/// <param name="statement">PartiQL statement.</param>
/// <param name="parameters">Parameters to execute.</param>
///
/// <returns>QLDB hash.</returns>
internal static QldbHash Dot(QldbHash seed, string statement, List <IIonValue> parameters)
{
QldbHash statementHash = QldbHash.ToQldbHash(statement);
foreach (var ionValue in parameters)
{
statementHash = statementHash.Dot(QldbHash.ToQldbHash(ionValue));
}
return(seed.Dot(statementHash));
}
/// <summary>
/// Execute the statement against QLDB and retrieve the result.
/// </summary>
///
/// <param name="statement">The PartiQL statement to be executed against QLDB.</param>
/// <param name="parameters">Parameters to execute.</param>
///
/// <returns>Result from executed statement.</returns>
///
/// <exception cref="AmazonServiceException">Thrown when there is an error executing against QLDB.</exception>
/// <exception cref="QldbDriverException">Thrown when this transaction has been disposed.</exception>
public IResult Execute(string statement, List <IIonValue> parameters)
{
ValidationUtils.AssertStringNotEmpty(statement, "statement");
if (parameters == null)
{
parameters = new List <IIonValue>();
}
this.qldbHash = Dot(this.qldbHash, statement, parameters);
ExecuteStatementResult executeStatementResult = this.session.ExecuteStatement(
this.txnId, statement, parameters);
return(new Result(this.session, this.txnId, executeStatementResult));
}
/// <summary>
/// Execute the statement against QLDB and retrieve the result.
/// </summary>
///
/// <param name="statement">The PartiQL statement to be executed against QLDB.</param>
/// <param name="parameters">Parameters to execute.</param>
/// <param name="cancellationToken">
/// A cancellation token that can be used by other objects or threads to receive notice of cancellation.
/// </param>
///
/// <returns>Result from executed statement.</returns>
///
/// <exception cref="AmazonServiceException">Thrown when there is an error executing against QLDB.</exception>
/// <exception cref="QldbDriverException">Thrown when this transaction has been disposed.</exception>
public async Task <IResult> Execute(string statement, List <IIonValue> parameters, CancellationToken cancellationToken = default)
{
ValidationUtils.AssertStringNotEmpty(statement, "statement");
if (parameters == null)
{
parameters = new List <IIonValue>();
}
this.qldbHash = Dot(this.qldbHash, statement, parameters);
ExecuteStatementResult executeStatementResult = await this.session.ExecuteStatement(
this.txnId, statement, parameters, cancellationToken);
return(new Result(this.session, this.txnId, executeStatementResult.FirstPage));
}