org.springframework.jdbc.object
Class SqlFunction<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>
                  org.springframework.jdbc.object.MappingSqlQuery<T>
                      org.springframework.jdbc.object.SqlFunction<T>

All Implemented Interfaces:

InitializingBean

public class SqlFunction<T>
extends MappingSqlQuery<T>

SQL "function" wrapper for a query that returns a single row of results. The default behavior is to return an int, but that can be overridden by using the constructor with an extra return type parameter.

Intended to use to call SQL functions that return a single result using a query like "select user()" or "select sysdate from dual". It is not intended for calling more complex stored functions or for using a CallableStatement to invoke a stored procedure or stored function. Use StoredProcedure or SqlCall for this type of processing.

This is a concrete class, which there is often no need to subclass. Code using this package can create an object of this type, declaring SQL and parameters, and then invoke the appropriate run method repeatedly to execute the function. Subclasses are only supposed to add specialized run methods for specific parameter and return types.

Like all RdbmsOperation objects, SqlFunction objects are thread-safe.

Author:

Rod Johnson, Juergen Hoeller, Jean-Pierre Pawlak

See Also:

StoredProcedure

Nested Class Summary

Nested classes/interfaces inherited from class org.springframework.jdbc.object.MappingSqlQueryWithParameters

MappingSqlQueryWithParameters.RowMapperImpl

Field Summary

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

logger

Constructor Summary

SqlFunction()
Constructor to allow use as a JavaBean.

SqlFunction(DataSource ds, String sql)
Create a new SqlFunction object with SQL, but without parameters.

SqlFunction(DataSource ds, String sql, int[] types)
Create a new SqlFunction object with SQL and parameters.

SqlFunction(DataSource ds, String sql, int[] types, Class<T> resultType)
Create a new SqlFunction object with SQL, parameters and a result type.

Method Summary

protected T	mapRow(ResultSet rs, int rowNum) This implementation of this method extracts a single value from the single row returned by the function.
int	run() Convenient method to run the function without arguments.
int	run(int parameter) Convenient method to run the function with a single int argument.
int	run(Object... parameters) Analogous to the SqlQuery.execute([]) method.
Object	runGeneric() Convenient method to run the function without arguments, returning the value as an object.
Object	runGeneric(int parameter) Convenient method to run the function with a single int argument.
Object	runGeneric(Object[] parameters) Analogous to the SqlQuery.findObject(Object[]) method.
void	setResultType(Class<T> resultType) Specify the type that the result object is required to match.

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

mapRow

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

newRowMapper

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

SqlFunction

public SqlFunction()

Constructor to allow use as a JavaBean. A DataSource, SQL and any parameters must be supplied before invoking the compile method and using this object.

See Also:

RdbmsOperation.setDataSource(javax.sql.DataSource), RdbmsOperation.setSql(java.lang.String), RdbmsOperation.compile()

SqlFunction

public SqlFunction(DataSource ds,
                   String sql)

Create a new SqlFunction object with SQL, but without parameters. Must add parameters or settle with none.

Parameters:

ds - DataSource to obtain connections from

sql - SQL to execute

SqlFunction

public SqlFunction(DataSource ds,
                   String sql,
                   int[] types)

Create a new SqlFunction object with SQL and parameters.

Parameters:

ds - DataSource to obtain connections from

sql - SQL to execute

types - SQL types of the parameters, as defined in the java.sql.Types class

See Also:

Types

SqlFunction

public SqlFunction(DataSource ds,
                   String sql,
                   int[] types,
                   Class<T> resultType)

Create a new SqlFunction object with SQL, parameters and a result type.

Parameters:

ds - DataSource to obtain connections from

sql - SQL to execute

types - SQL types of the parameters, as defined in the java.sql.Types class

resultType - the type that the result object is required to match

See Also:

setResultType(Class), Types

Method Detail

setResultType

public void setResultType(Class<T> resultType)

Specify the type that the result object is required to match.

If not specified, the result value will be exposed as returned by the JDBC driver.

mapRow

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

This implementation of this method extracts a single value from the single row returned by the function. If there are a different number of rows returned, this is treated as an error.

Specified by:

mapRow in class MappingSqlQuery<T>

Parameters:

rs - ResultSet we're working through

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

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.

run

public int run()

Convenient method to run the function without arguments.

Returns:

the value of the function

run

public int run(int parameter)

Convenient method to run the function with a single int argument.

Parameters:

parameter - single int parameter

Returns:

the value of the function

run

public int run(Object... parameters)

Analogous to the SqlQuery.execute([]) method. This is a generic method to execute a query, taken a number of arguments.

Parameters:

parameters - array of parameters. These will be objects or object wrapper types for primitives.

Returns:

the value of the function

runGeneric

public Object runGeneric()

Convenient method to run the function without arguments, returning the value as an object.

Returns:

the value of the function

runGeneric

public Object runGeneric(int parameter)

Convenient method to run the function with a single int argument.

Parameters:

parameter - single int parameter

Returns:

the value of the function as an Object

runGeneric

public Object runGeneric(Object[] parameters)

Analogous to the SqlQuery.findObject(Object[]) method. This is a generic method to execute a query, taken a number of arguments.

Parameters:

parameters - array of parameters. These will be objects or object wrapper types for primitives.

Returns:

the value of the function, as an Object

See Also:

SqlQuery.execute(Object[])