Package mondrian.rolap

Class SqlStatement

java.lang.Object
mondrian.rolap.SqlStatement
public class SqlStatement extends Object
SqlStatement contains a SQL statement and associated resources throughout its lifetime.

The goal of SqlStatement is to make tracing, error-handling and resource-management easier. None of the methods throws a SQLException; if an error occurs in one of the methods, the method wraps the exception in a RuntimeException describing the high-level operation, logs that the operation failed, and throws that RuntimeException.

If methods succeed, the method generates lifecycle logging such as the elapsed time and number of rows fetched.

There are a few obligations on the caller. The caller must:

  • call the handle(Throwable) method if one of the contained objects (say the ResultSet ) gives an error;
  • call the close() method if all operations complete successfully.
  • increment the rowCount field each time a row is fetched.

The close() method is idempotent. You are welcome to call it more than once.

SqlStatement is not thread-safe.

Since:
2.3
Author:
jhyde

  • Field Details

    • rowCount

      public int rowCount

  • Constructor Details

    • SqlStatement

      public SqlStatement(DataSource dataSource, String sql, List<SqlStatement.Type> types, int maxRows, int firstRowOrdinal, Locus locus, int resultSetType, int resultSetConcurrency, Util.Functor1<Void,Statement> callback)
      Creates a SqlStatement.
      Parameters:
      dataSource - Data source
      sql - SQL
      types - Suggested types of columns, or null; if present, must have one element for each SQL column; each not-null entry overrides deduced JDBC type of the column
      maxRows - Maximum rows; <= 0 means no maximum
      firstRowOrdinal - Ordinal of first row to skip to; <= 0 do not skip
      locus - Execution context of this statement
      resultSetType - Result set type
      resultSetConcurrency - Result set concurrency

  • Method Details

    • execute

      public void execute()
      Executes the current statement, and handles any SQLException.

    • close

      public void close()
      Closes all resources (statement, result set) held by this SqlStatement.

      If any of them fails, wraps them in a RuntimeException describing the high-level operation which this statement was performing. No further error-handling is required to produce a descriptive stack trace, unless you want to absorb the error.

      This method is idempotent.

    • getResultSet

      public ResultSet getResultSet()

    • handle

      public RuntimeException handle(Throwable e)
      Handles an exception thrown from the ResultSet, implicitly calls close(), and returns an exception which includes the full stack, including a description of the high-level operation.
      Parameters:
      e - Exception
      Returns:
      Runtime exception

    • guessTypes

      public List<SqlStatement.Type> guessTypes() throws SQLException
      Throws:
      SQLException

    • getDialect

      protected Dialect getDialect(RolapSchema schema)
      Retrieves dialect from schema or attempts to create it in case it is null
      Parameters:
      schema - rolap schema
      Returns:
      database dialect

    • createDialect

      protected Dialect createDialect()
      For tests

    • getAccessors

      public List<SqlStatement.Accessor> getAccessors()

    • getWrappedResultSet

      public ResultSet getWrappedResultSet()
      Returns the result set in a proxy which automatically closes this SqlStatement (and hence also the statement and result set) when the result set is closed.

      This helps to prevent connection leaks. The caller still has to remember to call ResultSet.close(), of course.

      Returns:
      Wrapped result set