org.sqlproc.engine
Class SqlOrder

java.lang.Object
  org.sqlproc.engine.SqlOrder

public class SqlOrder
extends Object

The list of ordering directives for the SQL Processor queries execution. The class layout is based on the Composite design pattern. Instances of this class can be obtained only using one of the factory methods.

For example there's a table PERSON with two columns - ID and NAME. The META SQL query can be the next one:

 ALL_PEOPLE(QRY)=
   select ID @id, NAME @name
   from PERSON
   {= where
    {& id=:id}
    {& UPPER(name)=:+name}
   }
   {#1 order by ID}
   {#2 order by NAME}
 ;
 

In the case of the SQL Processor invocation

 SqlEngine sqlEngine = sqlLoader.getQueryEngine("ALL_PEOPLE");
 List<Person> list = sqlEngine.query(session, Person.class, null, SqlOrder.getAscOrder(1));
 

the output list is sorted in ascending order based on the column ID.

In the case of the SQL Processor invocation

 SqlEngine sqlEngine = sqlLoader.getQueryEngine("ALL_PEOPLE");
 List<Person> list = sqlEngine.query(session, Person.class, new Object(), SqlOrder.getDescOrder(2));
 

the output list is sorted in descending order based on the column NAME.

For more info please see the Tutorials.

Author:

Vladimir Hudec

Nested Class Summary

static class

SqlOrder.Order The enumeration for the ordering directives.

Field Summary

private SqlOrder.Order	orderDirection The ordering direction (no ordering, ascending or descending).
private int	orderId The ordering id.
private List<SqlOrder>	orders The list of all ordering directives.

Constructor Summary

private	SqlOrder() Creates a new empty ordering directive list.
private	SqlOrder(int orderId, SqlOrder.Order orderDirection) Creates a new ordering directive list.

Method Summary

SqlOrder	addAscOrder(int orderId) Adds one more ascending ordering directive into the list of ordering directives.
SqlOrder	addDescOrder(int orderId) Adds one more descending ordering directive into the list of ordering directives.
SqlOrder	addOrder(int orderId) Adds one more ascending or descending ordering directive into the list of ordering directives.
static SqlOrder	getAscOrder(int orderId) The factory method.
static SqlOrder	getDescOrder(int orderId) The factory method.
static SqlOrder	getOrder() The factory method.
static SqlOrder	getOrder(int orderId) The factory method.
SqlOrder.Order	getOrderDirection() Returns the ordering direction (no ordering, ascending or descending).
int	getOrderId() Returns the ordering id.
List<SqlOrder>	getOrders() Returns the list of ordering directives.
String	toString() For debug purposes.

Methods inherited from class java.lang.Object

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

Field Detail

orderId

private int orderId

The ordering id. This value should correspond to the order number in the META SQL query {#NNN order by ...}.

orderDirection

private SqlOrder.Order orderDirection

The ordering direction (no ordering, ascending or descending).

orders

private List<SqlOrder> orders

The list of all ordering directives.

Constructor Detail

SqlOrder

private SqlOrder()

Creates a new empty ordering directive list. This constructor is a private one to prevent an instantiation without the help of factory methods.

SqlOrder

private SqlOrder(int orderId,
                 SqlOrder.Order orderDirection)

Creates a new ordering directive list. This constructor is a private one to prevent an instantiation without the help of factory methods.

Parameters:

orderId - the ordering id

orderDirection - the ordering direction

Method Detail

getOrder

public static SqlOrder getOrder()

The factory method.

Returns:

the empty ordering directive list

getAscOrder

public static SqlOrder getAscOrder(int orderId)

The factory method.

Parameters:

orderId - the ordering id

Returns:

the ordering directive list with one ascending ordering directive

getDescOrder

public static SqlOrder getDescOrder(int orderId)

The factory method.

Parameters:

orderId - the ordering id

Returns:

the ordering directive list with one descending ordering directive

getOrder

public static SqlOrder getOrder(int orderId)

The factory method.

Parameters:

orderId - the ordering id. Can be a negative one for a descending ordering directive.

Returns:

the ordering directive list with one ascending or descending ordering directive

addAscOrder

public SqlOrder addAscOrder(int orderId)

Adds one more ascending ordering directive into the list of ordering directives.

Parameters:

orderId - the ordering id

Returns:

the updated ordering directive list

addDescOrder

public SqlOrder addDescOrder(int orderId)

Adds one more descending ordering directive into the list of ordering directives.

Parameters:

orderId - the ordering id

Returns:

the updated ordering directive list

addOrder

public SqlOrder addOrder(int orderId)

Adds one more ascending or descending ordering directive into the list of ordering directives.

Parameters:

orderId - the ordering id. Can be a negative one for a descending ordering directive.

Returns:

the updated ordering directive list

getOrderId

public int getOrderId()

Returns the ordering id. This value should correspond to the order number in the META SQL query {#NNN order by ...}.

Returns:

the ordering id

getOrderDirection

public SqlOrder.Order getOrderDirection()

Returns the ordering direction (no ordering, ascending or descending).

Returns:

the ordering direction

getOrders

public List<SqlOrder> getOrders()

Returns the list of ordering directives.

Returns:

the list of ordering directives

toString

public String toString()

For debug purposes.

Overrides:

toString in class Object

Returns:

a String representation for a debug output