Spring Framework

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

java.lang.Object
  extended by org.springframework.jdbc.object.RdbmsOperation
      extended by org.springframework.jdbc.object.SqlOperation
          extended by org.springframework.jdbc.object.SqlQuery<T>
              extended by 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
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
MappingSqlQueryWithParameters()
          Constructor to allow use as a JavaBean
MappingSqlQueryWithParameters(javax.sql.DataSource ds, java.lang.String sql)
          Convenient constructor with DataSource and SQL string.
 
Method Summary
protected abstract  T mapRow(java.sql.ResultSet rs, int rowNum, java.lang.Object[] parameters, java.util.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(java.lang.Object[] parameters, java.util.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(javax.sql.DataSource ds,
                                     java.lang.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(java.lang.Object[] parameters,
                                    java.util.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(java.sql.ResultSet rs,
                            int rowNum,
                            java.lang.Object[] parameters,
                            java.util.Map context)
                     throws java.sql.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:
java.sql.SQLException - if there's an error extracting data. Subclasses can simply not catch SQLExceptions, relying on the framework to clean up.

Spring Framework