org.josef.jdbc

Class OrderByClause

java.lang.Object

org.josef.jdbc.OrderByClause

All Implemented Interfaces:

Serializable

@Status(stage=PRODUCTION,
        unitTests=COMPLETE)
 @Reviews(value=@Review(by="Kees Schotanus",at="2009-04-11"))
public class OrderByClause
extends Object
implements Serializable

Abstraction of a SQL order by clause.
For example: ORDER BY NAME, CODE DESC
This class creates a simple order by clause out of OrderByColumn columns. Use this class to create an 'ORDER BY' clause that can be used in combination with JP/QL.

Version:

1.0 $Revision: 6488 $

Author:

Kees Schotanus

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
OrderByClause(OrderByColumn... allowedOrderByColumns) Constructs this OrderByClause from the supplied allowedOrderByColumns.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object object) Determines whether this OrderByClause is equal to the supplied object.
OrderByColumn	getOrderByColumn(int ordinal) Gets an OrderByColumn by its ordinal number.
OrderByColumn	getOrderByColumn(String columnName) Gets an OrderByColumn by its column name.
int	hashCode() Computes the hash code of this OrderByClause.
void	setOrderByColumns(OrderByColumn... orderByColumns) Sets the columns to order by.
String	toOrderByString(Locale locale) Creates a String suitable to be used in an order by clause.
String	toString() Creates a String representation of this OrderByClause.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

OrderByClause

public OrderByClause(OrderByColumn... allowedOrderByColumns)

Constructs this OrderByClause from the supplied allowedOrderByColumns.
The first supplied OrderByColumn is the one that will be ordered upon.
Note: This constructor creates a defensive copy of the supplied orderByColumns.

Parameters:

allowedOrderByColumns - All columns that can be used to order by.

Throws:

NullPointerException - When the supplied allowedOrderByColumns is null.

IllegalArgumentException - When the supplied allowedOrderByColumns is empty.

Method Detail

setOrderByColumns

public void setOrderByColumns(OrderByColumn... orderByColumns)

Sets the columns to order by.
When the supplied orderByColumns are the ones that are currently used to order by, then the order of the first currently used order by column is toggled. When the supplied order differs from the existing order then all new columns will get the Order.ASCENDING order.
Note: You will normally want to use either getOrderByColumn(int) or getOrderByColumn(String) to locate a column and reuse it.

Parameters:

orderByColumns - The columns to order by.

Throws:

NullPointerException - When the supplied orderByColumns is null.

IllegalArgumentException - When the supplied orderByColumns is empty or contains an OrderByColumn that is not one of the allowed OrderByColumns supplied at construction time.

getOrderByColumn

public OrderByColumn getOrderByColumn(String columnName)

Gets an OrderByColumn by its column name.

Parameters:

columnName - The name of the column.

Returns:

The OrderByColumn with the supplied columnName.

Throws:

IllegalArgumentException - When no OrderByColumn with the supplied columnName exists.

getOrderByColumn

public OrderByColumn getOrderByColumn(int ordinal)

Gets an OrderByColumn by its ordinal number.

Parameters:

ordinal - The ordinal column number (0 based).

Returns:

The OrderByColumn with the supplied ordinal.

Throws:

IllegalArgumentException - When no OrderByColumn with the supplied ordinal exists.

toString

public String toString()

Creates a String representation of this OrderByClause.
The format is: allowed_column[,allowed_column]...:used_column[,used_column]...
The format of each individual column is determined by its OrderByColumn.toString() method.

Overrides:

toString in class Object

Returns:

String representation of this OrderByClause.

toOrderByString

public String toOrderByString(Locale locale)

Creates a String suitable to be used in an order by clause.
The returned String does not contain the ORDER BY key words, just the comma separated list of columns.

Parameters:

locale - The locale to localize the optional constants, that may be present in one of the order by columns.
When null is supplied, the default Locale will be used.

Returns:

A String suitable to be used in an order by clause.

equals

public boolean equals(Object object)

Determines whether this OrderByClause is equal to the supplied object.
Both order by clauses are equal when all of the following conditions are met:

• The supplied object is of type OrderByClause
• All order by columns in both the allowed and actually used array of order by columns should be the same. See: OrderByColumn.equals(Object).

Overrides:

equals in class Object

Parameters:

object - The object to compare to.

Returns:

True when this OrderByClause is equal to the supplied object.

hashCode

public int hashCode()

Computes the hash code of this OrderByClause.

Overrides:

hashCode in class Object

Returns:

Hash code of this OrderByClause.