org.springframework.jdbc.object

Class MappingSqlQueryWithParameters<T>

java.lang.Object

org.springframework.jdbc.object.RdbmsOperation

org.springframework.jdbc.object.SqlOperation

org.springframework.jdbc.object.SqlQuery<T>

org.springframework.jdbc.object.MappingSqlQueryWithParameters<T>

All Implemented Interfaces:

InitializingBean

Direct Known Subclasses:

MappingSqlQuery

public abstract class MappingSqlQueryWithParameters<T>
extends SqlQuery<T>

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.

Author:

Rod Johnson, Thomas Risberg, Jean-Pierre Pawlak

See Also:

MappingSqlQuery, SqlQuery

Nested Class Summary

Nested Classes

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

Field Summary

Fields inherited from class org.springframework.jdbc.object.RdbmsOperation

logger

Constructor Summary

Constructors

Constructor and Description
MappingSqlQueryWithParameters() Constructor to allow use as a JavaBean
MappingSqlQueryWithParameters(DataSource ds, String sql) Convenient constructor with DataSource and SQL string.

Method Summary

Modifier and Type	Method and Description
protected abstract T	mapRow(ResultSet rs, int rowNum, Object[] parameters, Map<?,?> 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[] parameters, Map<?,?> context) Implementation of protected abstract method.

Methods inherited from class org.springframework.jdbc.object.SqlQuery

execute, execute, execute, execute, execute, execute, execute, execute, execute, execute, execute, execute, executeByNamedParam, executeByNamedParam, findObject, findObject, findObject, findObject, findObject, findObject, findObject, findObject, findObject, findObject, findObjectByNamedParam, findObjectByNamedParam, getRowsExpected, setRowsExpected

Methods inherited from class org.springframework.jdbc.object.SqlOperation

compileInternal, getParsedSql, newPreparedStatementCreator, newPreparedStatementCreator, newPreparedStatementSetter, onCompileInternal

Methods inherited from class org.springframework.jdbc.object.RdbmsOperation

afterPropertiesSet, allowsUnusedParameters, checkCompiled, compile, declareParameter, getDeclaredParameters, getGeneratedKeysColumnNames, getJdbcTemplate, getResultSetType, getSql, isCompiled, isReturnGeneratedKeys, isUpdatableResults, setDataSource, setFetchSize, setGeneratedKeysColumnNames, setJdbcTemplate, setMaxRows, setParameters, setQueryTimeout, setResultSetType, setReturnGeneratedKeys, setSql, setTypes, setUpdatableResults, supportsLobParameters, validateNamedParameters, validateParameters

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MappingSqlQueryWithParameters

public MappingSqlQueryWithParameters()

Constructor to allow use as a JavaBean

MappingSqlQueryWithParameters

public MappingSqlQueryWithParameters(DataSource ds,
                                     String sql)

Convenient constructor with DataSource and SQL string.

Parameters:

ds - DataSource to use to get connections

sql - SQL to run

Method Detail

newRowMapper

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

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

Specified by:

newRowMapper in class SqlQuery<T>

Parameters:

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

context - 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.

See Also:

SqlQuery.execute(java.lang.Object[], java.util.Map<?, ?>)

mapRow

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 we're working through

rowNum - row number (from 0) we're up to

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

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

Returns:

an object of the result type

Throws:

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