com.moandjiezana.uncommons.dbutils

Interface ResultSetHandler<T>

Type Parameters:

T - the target type the input ResultSet will be converted to.

All Known Implementing Classes:

MapResultSetHandler

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface ResultSetHandler<T>

Converts ResultSets to other objects.

Field Summary

Fields

Modifier and Type	Field and Description
static ResultSetHandler<Void>	VOID Returns nothing.

Method Summary

Modifier and Type	Method and Description
T	handle(ResultSet rs) Turn the ResultSet into an instance of T.
static <T> ResultSetHandler<List<T>>	list(RowProcessor<T> rowProcessor)
static <K,V> ResultSetHandler<Map<K,V>>	map(String keyColumn, Class<K> keyClass, RowProcessor<V> rowProcessor)
static <T> ResultSetHandler<Optional<T>>	optional(ResultSetHandler<T> resultSetHandler)
static <T> ResultSetHandler<T>	single(RowProcessor<T> rowProcessor)

Field Detail

VOID

static final ResultSetHandler<Void> VOID

Returns nothing.

Method Detail

handle

T handle(ResultSet rs)
  throws Exception

Turn the ResultSet into an instance of T.

Parameters:

rs - The ResultSet to handle. It has not been touched before being passed to this method.

Returns:

An Object initialized with ResultSet data. Implementations may return null.

Throws:

Exception - if a database access error occurs

single

static <T> ResultSetHandler<T> single(RowProcessor<T> rowProcessor)

Type Parameters:

T - the instance type

Parameters:

rowProcessor - creates an instance of T

Returns:

an instance of T from the first row of the ResultSet or null, if the ResultSet is empty

optional

static <T> ResultSetHandler<Optional<T>> optional(ResultSetHandler<T> resultSetHandler)

Type Parameters:

T - the type of the instance wrapped in an Optional

Parameters:

resultSetHandler - processes the ResultSet

Returns:

the result of invoking the underlying ResultSetHandler, wrapped in an Optional.

list

static <T> ResultSetHandler<List<T>> list(RowProcessor<T> rowProcessor)

Type Parameters:

T - the instance type

Parameters:

rowProcessor - creates an instance of T

Returns:

a List of T or an empty List if the ResultSet is empty.

map

static <K,V> ResultSetHandler<Map<K,V>> map(String keyColumn,
                                            Class<K> keyClass,
                                            RowProcessor<V> rowProcessor)

Type Parameters:

K - the type of the Map keys

V - the type of the Map values

Parameters:

keyColumn - the name of the column the map key can be extracted from

keyClass - the type of the Map keys

rowProcessor - creates an instance of V

Returns:

a Map with keys taken from keyColumn or an empty Map if the ResultSet is empty.

See Also:

MapResultSetHandler