org.springframework.jdbc.object
Class MappingSqlQueryWithParameters
java.lang.Object
org.springframework.jdbc.object.RdbmsOperation
org.springframework.jdbc.object.SqlOperation
org.springframework.jdbc.object.SqlQuery
org.springframework.jdbc.object.MappingSqlQueryWithParameters
- All Implemented Interfaces:
- InitializingBean
- Direct Known Subclasses:
- MappingSqlQuery
- public abstract class MappingSqlQueryWithParameters
- extends SqlQuery
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
Method Summary |
protected abstract Object |
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 ResultReader |
newResultReader(int rowsExpected,
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, findObject, findObject, findObject, findObject, findObject, findObject, findObject, findObject, findObject, findObject, getRowsExpected, setRowsExpected |
Methods inherited from class org.springframework.jdbc.object.RdbmsOperation |
afterPropertiesSet, compile, declareParameter, getDeclaredParameters, getGeneratedKeysColumnNames, getJdbcTemplate, getResultSetType, getSql, isCompiled, isReturnGeneratedKeys, isUpdatableResults, setDataSource, setFetchSize, setGeneratedKeysColumnNames, setJdbcTemplate, setMaxRows, setResultSetType, setReturnGeneratedKeys, setSql, setTypes, setUpdatableResults, supportsLobParameters, validateParameters |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
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 connectionssql
- SQL to run
newResultReader
protected ResultReader newResultReader(int rowsExpected,
Object[] parameters,
Map context)
- Implementation of protected abstract method. This invokes the subclass's
implementation of the mapRow() method.
- Specified by:
newResultReader
in class SqlQuery
- Parameters:
rowsExpected
- If 0, we don't know how many rows to expect.
This parameter can be ignored, but may help some implementations
choose the most efficient Collection type: e.g. ArrayList
instead of LinkedList for large result sets.parameters
- parameters to the execute() method, in case subclass
is interested. May be null if there were no parameters.- See Also:
SqlQuery.execute(java.lang.Object[], java.util.Map)
mapRow
protected abstract Object 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 throughrowNum
- row number (from 0) we're up toparameters
- 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.
Copyright (C) 2003-2004 The Spring Framework Project.