Package org.apache.commons.dbutils

# Interface ColumnHandler<T>

Type Parameters:
  `T` - The return type.

All Known Implementing Classes:
  `BooleanColumnHandler`, `ByteColumnHandler`, `DoubleColumnHandler`, `FloatColumnHandler`, `IntegerColumnHandler`, `LongColumnHandler`, `ShortColumnHandler`, `SQLXMLColumnHandler`, `StringColumnHandler`, `TimestampColumnHandler`

public interface ColumnHandler<T>
Defines how to process columns when constructing a bean from a `ResultSet`. Instances do the work of retrieving data from a `ResultSet`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `T`
  `apply(ResultSet resultSet, int columnIndex)`
  Retrieves the current row's column value from a `ResultSet` and stores it into an instance of `propType`.
  `boolean`
  `match(Class<?> propType)`
  Tests whether to handle a column targeted for a value type matching `propType`.

- ## Method Details

  - ### apply

    T apply(ResultSet resultSet, int columnIndex) throws SQLException
    Retrieves the current row's column value from a `ResultSet` and stores it into an instance of `propType`. This method is only called if `match(Class)` returns true.
    Parameters:
      `resultSet` - The source result set. This must be on the correct row.
      `columnIndex` - The position of the column to retrieve, a 1-based index.
    Returns:
      The converted value or the original value if something doesn't work out.
    Throws:
      `SQLException` - if the columnIndex is not valid; if a database access error occurs or this method is called on a closed result set

  - ### match

    boolean match(Class<?> propType)
    Tests whether to handle a column targeted for a value type matching `propType`.
    Parameters:
      `propType` - The type of the target parameter.
    Returns:
      true is this property handler handles this `propType`; false otherwise.