Reusable RDBMS query in which concrete subclasses must implement the abstract mapRow(ResultSet, int) method to map each row of the JDBC ResultSet into an object.

Such manual mapping is usually preferable to "automatic" mapping using reflection, which can become complex in non-trivial cases. For example, the present class allows different objects to be used for different rows (for example, if a subclass is indicated). It allows computed fields to be set. And there's no need for ResultSet columns to have the same names as bean properties. The Pareto Principle in action: going the extra mile to automate the extraction process makes the framework much more complex and delivers little real benefit.

Subclasses can be constructed providing SQL, parameter types and a DataSource. SQL will often vary between subclasses.

Nested and Inner Type Summary

Modifier and Type	Class and Description
protected class	MappingSqlQueryWithParameters.RowMapperImpl Implementation of RowMapper that calls the enclosing class's `mapRow` method for each row.

Access	Constructor and Description
public	MappingSqlQueryWithParameters() Constructor to allow use as a JavaBean.
public	MappingSqlQueryWithParameters(DataSource the DataSource to use to get connections ds, String the SQL to run sql) Convenient constructor with DataSource and SQL string.

Method Summary

Modifier and Type Method and Description

Modifier and Type	Method and Description
protected abstract T	Returns: an object of the result type mapRow(ResultSet the ResultSet we're working through rs, int row number (from 0) we're up to rowNum, Object[] to the query (passed to the execute() method). Subclasses are rarely interested in these. It can be `null` if there are no parameters. parameters, Map<?, ?> passed to the execute() method. It can be `null` if no contextual information is need. context) Subclasses must implement this method to convert each row of the ResultSet into an object of the result type.
protected RowMapper<T>	newRowMapper(Object[] the parameters to the `execute()` method, in case subclass is interested; may be `null` if there were no parameters. parameters, Map<?, ?> the contextual information passed to the `mapRow` callback method. The JDBC operation itself doesn't rely on this parameter, but it can be useful for creating the objects of the result list. context) Implements abstract org.springframework.jdbc.object.SqlQuery.newRowMapper. Implementation of protected abstract method.

protected abstract T

Returns:

an object of the result type

mapRow(ResultSet

the ResultSet we're working through

rs, int

row number (from 0) we're up to

rowNum, Object[]

to the query (passed to the execute() method). Subclasses are rarely interested in these. It can be null if there are no parameters.

parameters, Map<?, ?>

passed to the execute() method. It can be null if no contextual information is need.

context)

Subclasses must implement this method to convert each row of the ResultSet into an object of the result type.

protected RowMapper<T>

newRowMapper(Object[]

the parameters to the execute() method, in case subclass is interested; may be null if there were no parameters.

parameters, Map<?, ?>

the contextual information passed to the mapRow callback method. The JDBC operation itself doesn't rely on this parameter, but it can be useful for creating the objects of the result list.

context)

Implements abstract org.springframework.jdbc.object.SqlQuery.newRowMapper.

Implementation of protected abstract method.

MappingSqlQueryWithParameters	back to summary
public MappingSqlQueryWithParameters() Constructor to allow use as a JavaBean.

MappingSqlQueryWithParameters	back to summary
public MappingSqlQueryWithParameters(DataSource ds, String sql) Convenient constructor with DataSource and SQL string. Parameters ds:DataSource the DataSource to use to get connections sql:String the SQL to run

Method Detail

mapRow back to summary

mapRow	back to summary
protected abstract T mapRow(ResultSet rs, int rowNum, Object[] parameters, Map<?, ?> context) throws SQLException Subclasses must implement this method to convert each row of the ResultSet into an object of the result type. Parameters rs:ResultSet the ResultSet we're working through rowNum:int row number (from 0) we're up to parameters:Object[] to the query (passed to the execute() method). Subclasses are rarely interested in these. It can be `null` if there are no parameters. context:Map<?, ?> passed to the execute() method. It can be `null` if no contextual information is need. Returns:T an object of the result type Annotations @Nullable Exceptions SQLException: if there's an error extracting data. Subclasses can simply not catch SQLExceptions, relying on the framework to clean up.

protected abstract T mapRow(ResultSet rs, int rowNum, Object[] parameters, Map<?, ?> context) throws SQLException

Subclasses must implement this method to convert each row of the ResultSet into an object of the result type.

Parameters

rs:ResultSet: the ResultSet we're working through
rowNum:int: row number (from 0) we're up to
parameters:Object[]: to the query (passed to the execute() method). Subclasses are rarely interested in these. It can be null if there are no parameters.
context:Map<?, ?>: passed to the execute() method. It can be null if no contextual information is need.

Returns:T

an object of the result type

Annotations

@Nullable

Exceptions

SQLException:: if there's an error extracting data. Subclasses can simply not catch SQLExceptions, relying on the framework to clean up.

newRowMapper back to summary

newRowMapper	back to summary
protected RowMapper<T> newRowMapper(Object[] parameters, Map<?, ?> context) Implements abstract org.springframework.jdbc.object.SqlQuery.newRowMapper. Implementation of protected abstract method. This invokes the subclass's implementation of the mapRow() method. Parameters parameters:Object[] Doc from org.springframework.jdbc.object.SqlQuery.newRowMapper. the parameters to the `execute()` method, in case subclass is interested; may be `null` if there were no parameters. context:Map<?, ?> Doc from org.springframework.jdbc.object.SqlQuery.newRowMapper. the contextual information passed to the `mapRow` callback method. The JDBC operation itself doesn't rely on this parameter, but it can be useful for creating the objects of the result list. Annotations @Override

protected RowMapper<T> newRowMapper(Object[] parameters, Map<?, ?> context)

Implements abstract org.springframework.jdbc.object.SqlQuery.newRowMapper.

Implementation of protected abstract method. This invokes the subclass's implementation of the mapRow() method.

Parameters

parameters:Object[]

Doc from org.springframework.jdbc.object.SqlQuery.newRowMapper.

the parameters to the execute() method, in case subclass is interested; may be null if there were no parameters.

context:Map<?, ?>

Doc from org.springframework.jdbc.object.SqlQuery.newRowMapper.

the contextual information passed to the mapRow callback method. The JDBC operation itself doesn't rely on this parameter, but it can be useful for creating the objects of the result list.

Annotations

@Override

org.springframework.jdbc.object back to summary

protected Class MappingSqlQueryWithParameters.RowMapperImpl

Class Inheritance

extends Object
implements RowMapper<T>

java.lang.Object
org.springframework.jdbc.object.MappingSqlQueryWithParameters.RowMapperImpl

All Implemented Interfaces

org.springframework.jdbc.core.RowMapper

Implementation of RowMapper that calls the enclosing class's mapRow method for each row.

Field Summary

Modifier and Type	Field and Description
private final Map<?, ?>	context
private final Object[]	params

Constructor Summary

Access	Constructor and Description
public	RowMapperImpl(Object[] parameters, Map<?, ?> context) Use an array results.

Method Summary

Modifier and Type	Method and Description
public T	mapRow(ResultSet the `ResultSet` to map (pre-initialized for the current row) rs, int the number of the current row rowNum) Implements org.springframework.jdbc.core.RowMapper.mapRow. Implementations must implement this method to map each row of data in the `ResultSet`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

context	back to summary
private final Map<?, ?> context Annotations @Nullable

params	back to summary
private final Object[] params Annotations @Nullable

Constructor Detail

RowMapperImpl	back to summary
public RowMapperImpl(Object[] parameters, Map<?, ?> context) Use an array results. More efficient if we know how many results to expect.

Method Detail

mapRow back to summary

mapRow	back to summary
public T mapRow(ResultSet rs, int rowNum) throws SQLException Implements org.springframework.jdbc.core.RowMapper.mapRow. Doc from org.springframework.jdbc.core.RowMapper.mapRow. Implementations must implement this method to map each row of data in the `ResultSet`. This method should not call `next()` on the `ResultSet`; it is only supposed to map values of the current row. Parameters rs:ResultSet the `ResultSet` to map (pre-initialized for the current row) rowNum:int the number of the current row Returns:T the result object for the current row (may be `null`) Annotations @Override @Nullable Exceptions SQLException: if an SQLException is encountered while getting column values (that is, there's no need to catch SQLException)

public T mapRow(ResultSet rs, int rowNum) throws SQLException

Implements org.springframework.jdbc.core.RowMapper.mapRow.

Doc from org.springframework.jdbc.core.RowMapper.mapRow.

Implementations must implement this method to map each row of data in the ResultSet. This method should not call next() on the ResultSet; it is only supposed to map values of the current row.

Parameters

rs:ResultSet: the ResultSet to map (pre-initialized for the current row)
rowNum:int: the number of the current row

Returns:T

the result object for the current row (may be null)

Annotations

@Override
@Nullable

Exceptions

SQLException:: if an SQLException is encountered while getting column values (that is, there's no need to catch SQLException)

public abstract Class MappingSqlQueryWithParameters<T>

Nested and Inner Type Summary

Constructor Summary

Method Summary

Constructor Detail

Method Detail

protected Class MappingSqlQueryWithParameters.RowMapperImpl

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail