com.ing.data.cassandra.jdbc

Interface CassandraResultSetJsonSupport

All Superinterfaces:

AutoCloseable, ResultSet, Wrapper

All Known Implementing Classes:

CassandraResultSet

public interface CassandraResultSetJsonSupport
extends ResultSet

Extension of ResultSet interface providing additional methods specific to Cassandra result sets for JSON-formatted results provided by Cassandra features SELECT JSON and toJson().

The CQL SELECT queries using JSON support will return a map where the keys are the column labels. So, don't forget that if you use JSON formatting for only one column of type T, the result will be an object like this one: { "columnLabel": { ... } } and should be deserialized to an object extending Map<String, T> and not directly to T.

Using the methods defined into this interface requires some considerations relative to the acceptable types for result deserialization. The table below lists the acceptable type(s) in the target object to which the JSON will be deserialized. Note that all non-collection types can also be deserialized to String and the collections can be deserialized to List (for CQL types list, set and tuple) or Map (for CQL types map and udt) of String items.

CQL Type	JSON type	Acceptable Java types
ascii	string	String
bigint	integer	Number
blob	string	ByteBuffer
boolean	boolean	Boolean
date	string	Date, LocalDate
decimal	float	Number
double	float	Number
float	float	Number
inet	string	InetAddress
int	integer	Number
list	list	List
map	map	Map
set	list	Set, List
smallint	integer	Number
text	string	String
time	string	LocalTime
timestamp	string	OffsetDateTime
timeuuid	string	UUID
tinyint	integer	Number
tuple	list	List
udt	map	Map or a suitable object to which the map can be deserialized
uuid	string	UUID
varchar	string	String
varint	integer	Number
vector	list	List

See: CQL reference for JSON support.

Field Summary

Fields inherited from interface java.sql.ResultSet

CLOSE_CURSORS_AT_COMMIT, CONCUR_READ_ONLY, CONCUR_UPDATABLE, FETCH_FORWARD, FETCH_REVERSE, FETCH_UNKNOWN, HOLD_CURSORS_OVER_COMMIT, TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE, TYPE_SCROLL_SENSITIVE

Method Summary

Modifier and Type	Method and Description
<T> T	getObjectFromJson(Class<T> type) Retrieves the value of the column labelled "[json]", containing a JSON string, in the current row of this ResultSet object as an instance of type T.
<T> T	getObjectFromJson(int columnIndex, Class<T> type) Retrieves the value of the designated column in the current row of this ResultSet object as an instance of type T from a JSON string.
<T> T	getObjectFromJson(String columnLabel, Class<T> type) Retrieves the value of the designated column in the current row of this ResultSet object as an instance of type T from a JSON string.

Methods inherited from interface java.sql.ResultSet

absolute, afterLast, beforeFirst, cancelRowUpdates, clearWarnings, close, deleteRow, findColumn, first, getArray, getArray, getAsciiStream, getAsciiStream, getBigDecimal, getBigDecimal, getBigDecimal, getBigDecimal, getBinaryStream, getBinaryStream, getBlob, getBlob, getBoolean, getBoolean, getByte, getByte, getBytes, getBytes, getCharacterStream, getCharacterStream, getClob, getClob, getConcurrency, getCursorName, getDate, getDate, getDate, getDate, getDouble, getDouble, getFetchDirection, getFetchSize, getFloat, getFloat, getHoldability, getInt, getInt, getLong, getLong, getMetaData, getNCharacterStream, getNCharacterStream, getNClob, getNClob, getNString, getNString, getObject, getObject, getObject, getObject, getObject, getObject, getRef, getRef, getRow, getRowId, getRowId, getShort, getShort, getSQLXML, getSQLXML, getStatement, getString, getString, getTime, getTime, getTime, getTime, getTimestamp, getTimestamp, getTimestamp, getTimestamp, getType, getUnicodeStream, getUnicodeStream, getURL, getURL, getWarnings, insertRow, isAfterLast, isBeforeFirst, isClosed, isFirst, isLast, last, moveToCurrentRow, moveToInsertRow, next, previous, refreshRow, relative, rowDeleted, rowInserted, rowUpdated, setFetchDirection, setFetchSize, updateArray, updateArray, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateBigDecimal, updateBigDecimal, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBoolean, updateBoolean, updateByte, updateByte, updateBytes, updateBytes, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateClob, updateClob, updateClob, updateClob, updateClob, updateClob, updateDate, updateDate, updateDouble, updateDouble, updateFloat, updateFloat, updateInt, updateInt, updateLong, updateLong, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNString, updateNString, updateNull, updateNull, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateRef, updateRef, updateRow, updateRowId, updateRowId, updateShort, updateShort, updateSQLXML, updateSQLXML, updateString, updateString, updateTime, updateTime, updateTimestamp, updateTimestamp, wasNull

Methods inherited from interface java.sql.Wrapper

isWrapperFor, unwrap

Method Detail

getObjectFromJson

<T> T getObjectFromJson(int columnIndex,
                        Class<T> type)
                 throws SQLException

Retrieves the value of the designated column in the current row of this ResultSet object as an instance of type T from a JSON string.

Typically, this method can be called on a result set returned by a CQL query like:
SELECT JSON col1, col2 FROM exampleTable;
or on a result column defined with the function toJson().

Type Parameters:

T - The type of the object represented by the JSON string.

Parameters:

columnIndex - The column index (the first column is 1).

type - The class representing the Java data type to convert the designated column to.

Returns:

The column value converted to an instance of T. If the value is SQL NULL, it should return null.

Throws:

SQLException - if the columnIndex is not valid; if a database access error occurs; if this method is called on a closed result set or if the value is cannot be parsed to an object of type T.

See Also:

Cassandra JSON support

getObjectFromJson

<T> T getObjectFromJson(String columnLabel,
                        Class<T> type)
                 throws SQLException

Retrieves the value of the designated column in the current row of this ResultSet object as an instance of type T from a JSON string.

Typically, this method can be called on a result set returned by a CQL query like:
SELECT JSON col1, col2 FROM exampleTable;
or on a result column defined with the function toJson().

Type Parameters:

T - The type of the object represented by the JSON string.

Parameters:

columnLabel - The label for the column specified with the SQL AS clause. If the SQL AS clause was not specified, then the label is the name of the column.

type - The class representing the Java data type to convert the designated column to.

Returns:

The column value converted to an instance of T. If the value is SQL NULL, it should return null.

Throws:

SQLException - if the columnIndex is not valid; if a database access error occurs; if this method is called on a closed result set or if the value is cannot be parsed to an object of type T.

See Also:

Cassandra JSON support

getObjectFromJson

<T> T getObjectFromJson(Class<T> type)
                 throws SQLException

Retrieves the value of the column labelled "[json]", containing a JSON string, in the current row of this ResultSet object as an instance of type T.

Typically, this method can be called on a result set returned by a CQL query like:
SELECT JSON * FROM exampleTable;

Type Parameters:

T - The type of the object represented by the JSON string.

Parameters:

type - The class representing the Java data type to convert the column value to.

Returns:

The column value converted to an instance of T. If the value is SQL NULL, it should return null.

Throws:

SQLException - if the columnIndex is not valid; if a database access error occurs; if this method is called on a closed result set or if the value is cannot be parsed to an object of type T.

See Also:

Cassandra JSON support