io.r2dbc.proxy.listener

Interface BindParameterConverter

public interface BindParameterConverter

Callback for Connection.createStatement(String) and bind operations(bind and bindNull).

Author:

Tadaya Tsuyukubo

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	BindParameterConverter.BindOperation Represent bind operation(bind and bindNull).

Method Summary

Modifier and Type	Method and Description
static BindParameterConverter	create() Create default BindParameterConverter.
default void	onBind(BindInfo info, io.r2dbc.spi.Statement proxyStatement, BindParameterConverter.BindOperation defaultBinding) Callback method for bind operations(bind and bindNull) on Statement before actually performing those methods.
default String	onCreateStatement(String query, StatementInfo info) Convert the given query to another one at Connection.createStatement(String).

Method Detail

create

static BindParameterConverter create()

Create default BindParameterConverter.

Returns:

a bindParameterConverter

onCreateStatement

default String onCreateStatement(String query,
                                 StatementInfo info)

Convert the given query to another one at Connection.createStatement(String).

This method will be called when Connection.createStatement(String) is called(before actually performing), and the returned query will be used as its input. Additionally, in this method, any information can be stored in StatementInfo.getValueStore() and they will be available at onBind(BindInfo, Statement, BindOperation).

Typical usage would be parsing the parameters in query and convert it to the parameter placeholder that target database supports. In addition, construct a map that contains parameter indexes by the place holder to avoid parsing query again at onBind(BindInfo, Statement, BindOperation).

For example, convert a query that uses colon prefix for named parameters: "INSERT INTO names (first_name) VALUES (:FIRST_NAME)" to "INSERT INTO names (first_name) VALUES (?)", and construct a map ":FIRST_NAME" = 0 (index).

Parameters:

query - original query

info - contextual information for Connection.createStatement(String).

Returns:

converted query

onBind

default void onBind(BindInfo info,
                    io.r2dbc.spi.Statement proxyStatement,
                    BindParameterConverter.BindOperation defaultBinding)

Callback method for bind operations(bind and bindNull) on Statement before actually performing those methods. Implementation of this method can modify the actual behavior. When calling the defaultBinding.proceed() performs the actual invocation of original bind operation, and returns proxy Statement. To skip actual invocation of the original bind operation, simply returns proxyStatement.

Parameters:

info - contextual information for bind and bindNull.

proxyStatement - proxy Statement.

defaultBinding - perform default bind operations and returns a result of proxy Statement