Spring Framework

org.springframework.jdbc.object
Class SqlFunction<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>
                  extended by org.springframework.jdbc.object.MappingSqlQuery<T>
                      extended by 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(javax.sql.DataSource ds, java.lang.String sql)
          Create a new SqlFunction object with SQL, but without parameters.
SqlFunction(javax.sql.DataSource ds, java.lang.String sql, int[] types)
          Create a new SqlFunction object with SQL and parameters.
SqlFunction(javax.sql.DataSource ds, java.lang.String sql, int[] types, java.lang.Class<T> resultType)
          Create a new SqlFunction object with SQL, parameters and a result type.
 
Method Summary
protected  T mapRow(java.sql.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(java.lang.Object... parameters)
          Analogous to the SqlQuery.execute([]) method.
 java.lang.Object runGeneric()
          Convenient method to run the function without arguments, returning the value as an object.
 java.lang.Object runGeneric(int parameter)
          Convenient method to run the function with a single int argument.
 java.lang.Object runGeneric(java.lang.Object[] parameters)
          Analogous to the SqlQuery.findObject(Object[]) method.
 void setResultType(java.lang.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(javax.sql.DataSource ds,
                   java.lang.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(javax.sql.DataSource ds,
                   java.lang.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(javax.sql.DataSource ds,
                   java.lang.String sql,
                   int[] types,
                   java.lang.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(java.lang.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(java.sql.ResultSet rs,
                   int rowNum)
            throws java.sql.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:
java.sql.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(java.lang.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 java.lang.Object runGeneric()
Convenient method to run the function without arguments, returning the value as an object.

Returns:
the value of the function

runGeneric

public java.lang.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 java.lang.Object runGeneric(java.lang.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[])

Spring Framework