org.eclipse.persistence.jpa.jpql.tools.model.query

Class OrderByItemStateObject

java.lang.Object

org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractStateObject

org.eclipse.persistence.jpa.jpql.tools.model.query.OrderByItemStateObject

All Implemented Interfaces:

StateObject

public class OrderByItemStateObject
extends AbstractStateObject

An ORDER BY item must be one of the following:

1. A state_field_path_expression that evaluates to an orderable state field of an entity or embeddable class abstract schema type designated in the SELECT clause by one of the following:
   • A general_identification_variable
   • A single_valued_object_path_expression
2. A state_field_path_expression that evaluates to the same state field of the same entity or embeddable abstract schema type as a state_field_path_expression in the SELECT clause
3. A result_variable that refers to an orderable item in the SELECT clause for which the same result_variable has been specified. This may be the result of an aggregate_expression, a scalar_expression, or a state_field_path_expression in the SELECT clause.

The keyword ASC specifies that ascending ordering be used for the associated ORDER BY item; the keyword DESC specifies that descending ordering be used. Ascending ordering is the default.

JPA 1.0:

BNF: orderby_item ::= state_field_path_expression [ ASC | DESC ]

JPA 2.0

BNF: orderby_item ::= state_field_path_expression | result_variable [ ASC | DESC ]

Version:

2.4

See Also:

OrderByItem

Author:

Pascal Filion

Since:

2.4

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	ORDERING_PROPERTY Notifies the ordering property has changed.
static java.lang.String	STATE_OBJECT_PROPERTY Notifies the ordering property has changed.

Constructor Summary

Constructors

Constructor and Description
OrderByItemStateObject(OrderByClauseStateObject parent) Creates a new OrderByItemStateObject.
OrderByItemStateObject(OrderByClauseStateObject parent, OrderByItem.Ordering ordering) Creates a new OrderByItemStateObject.
OrderByItemStateObject(OrderByClauseStateObject parent, StateObject stateObject, OrderByItem.Ordering ordering) Creates a new OrderByItemStateObject.
OrderByItemStateObject(OrderByClauseStateObject parent, java.lang.String jpqlFragment, OrderByItem.Ordering ordering) Creates a new OrderByItemStateObject.

Method Summary

Modifier and Type	Method and Description
void	accept(StateObjectVisitor visitor) Visits this StateObject by the given visitor.
protected void	addChildren(java.util.List<StateObject> children) Adds the children of this StateObject to the given list.
OrderByItem	getExpression() Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
OrderByItem.Ordering	getOrdering() Returns the enum constant representing the ordering type.
OrderByClauseStateObject	getParent() Returns the parent of this StateObject.
StateObject	getStateObject() Returns the StateObject representing the value used for ordering.
boolean	hasStateObject() Determines whether the StateObject representing the value used for ordering has been defined.
boolean	isAscending() Determines whether the ordering was specified as being ascendant.
boolean	isDefault() Determines whether the ordering was not specified.
boolean	isDescending() Determines whether the ordering was specified as being descendant.
boolean	isEquivalent(StateObject stateObject) Determines whether the given StateObject is equivalent to this one, i.e. the information of both StateObject is the same.
void	parse(java.lang.String jpqlFragment) Parses the given JPQL fragment, which represents either a state-field pathe expression or a result variable, and creates the StateObject.
void	removeOrdering() Removes the ordering if it's specified, otherwise do nothing.
void	setExpression(OrderByItem expression) Keeps a reference of the parsed object object, which should only be done when this object is instantiated during the conversion of a parsed JPQL query into StateObjects.
void	setOrdering(OrderByItem.Ordering ordering) Sets the enum constant representing the ordering type.
void	setStateObject(StateObject stateObject) Sets the StateObject representing the value used for ordering.
protected void	toTextInternal(java.lang.Appendable writer) Prints out a string representation of this StateObject, which should not be used to define a true string representation of a JPQL query but should be used for debugging purposes.

Methods inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractStateObject

acceptUnknownVisitor, acceptUnknownVisitor, addProblems, addPropertyChangeListener, areEquivalent, buildProblem, buildProblem, buildStateObject, buildStateObjects, checkParent, children, decorate, equals, findIdentificationVariable, firePropertyChanged, getChangeSupport, getDeclaration, getDecorator, getGrammar, getManagedTypeProvider, getQueryBuilder, getRoot, getType, getType, getTypeHelper, getTypeRepository, hashCode, initialize, isDecorated, parent, parent, parent, removePropertyChangeListener, setExpression, setParent, toString, toString, toStringInternal, toStringItems, toText

Methods inherited from class java.lang.Object

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

Field Detail

ORDERING_PROPERTY

public static final java.lang.String ORDERING_PROPERTY

Notifies the ordering property has changed.

See Also:

Constant Field Values

STATE_OBJECT_PROPERTY

public static final java.lang.String STATE_OBJECT_PROPERTY

Notifies the ordering property has changed.

See Also:

Constant Field Values

Constructor Detail

OrderByItemStateObject

public OrderByItemStateObject(OrderByClauseStateObject parent)

Creates a new OrderByItemStateObject.

Parameters:

parent - The parent of this state object, which cannot be null

Throws:

java.lang.NullPointerException - The given parent cannot be null

OrderByItemStateObject

public OrderByItemStateObject(OrderByClauseStateObject parent,
                              OrderByItem.Ordering ordering)

Creates a new OrderByItemStateObject.

Parameters:

parent - The parent of this state object, which cannot be null

Throws:

java.lang.NullPointerException - The given parent cannot be null

OrderByItemStateObject

public OrderByItemStateObject(OrderByClauseStateObject parent,
                              StateObject stateObject,
                              OrderByItem.Ordering ordering)

Creates a new OrderByItemStateObject.

Parameters:

parent - The parent of this state object, which cannot be null

stateObject - The StateObject of the item

ordering - One of the possible OrderByItem.Ordering choice

Throws:

java.lang.NullPointerException - The given parent cannot be null

OrderByItemStateObject

public OrderByItemStateObject(OrderByClauseStateObject parent,
                              java.lang.String jpqlFragment,
                              OrderByItem.Ordering ordering)

Creates a new OrderByItemStateObject.

Parameters:

parent - The parent of this state object, which cannot be null

jpqlFragment - The JPQL fragment representing the ordering item

ordering - One of the possible OrderByItem.Ordering choice

Throws:

java.lang.NullPointerException - The given parent cannot be null

Method Detail

accept

public void accept(StateObjectVisitor visitor)

Visits this StateObject by the given visitor.

Parameters:

visitor - The visitor to visit this object

addChildren

protected void addChildren(java.util.List<StateObject> children)

Adds the children of this StateObject to the given list.

Overrides:

addChildren in class AbstractStateObject

Parameters:

children - The list used to store the children

getExpression

public OrderByItem getExpression()

Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.

Specified by:

getExpression in interface StateObject

Overrides:

getExpression in class AbstractStateObject

Returns:

The parsed object when a JPQL query is parsed and converted into a StateObject or null when the JPQL query is manually created (i.e. not from a string)

getOrdering

public OrderByItem.Ordering getOrdering()

Returns the enum constant representing the ordering type.

Returns:

The constant representing the ordering, in the case the ordering was not parsed, then OrderByItem.Ordering.DEFAULT is returned

getParent

public OrderByClauseStateObject getParent()

Returns the parent of this StateObject.

Specified by:

getParent in interface StateObject

Overrides:

getParent in class AbstractStateObject

Returns:

Returns the parent of this StateObject, which is null only when this is the root of the hierarchy

getStateObject

public StateObject getStateObject()

Returns the StateObject representing the value used for ordering.

Returns:

The StateObject representing the value used for ordering

hasStateObject

public boolean hasStateObject()

Determines whether the StateObject representing the value used for ordering has been defined.

Returns:

true if the ordering value is defined; false otherwise

isAscending

public boolean isAscending()

Determines whether the ordering was specified as being ascendant.

Returns:

true if ASC was parsed; false otherwise

isDefault

public boolean isDefault()

Determines whether the ordering was not specified.

Returns:

true if no ordering was parsed; false otherwise

isDescending

public boolean isDescending()

Determines whether the ordering was specified as being descendant.

Returns:

true if DESC was parsed; false otherwise

isEquivalent

public boolean isEquivalent(StateObject stateObject)

Determines whether the given StateObject is equivalent to this one, i.e. the information of both StateObject is the same.

Specified by:

isEquivalent in interface StateObject

Overrides:

isEquivalent in class AbstractStateObject

Parameters:

stateObject - The StateObject to compare its content to this one

Returns:

true if both object are equivalent; false otherwise

parse

public void parse(java.lang.String jpqlFragment)

Parses the given JPQL fragment, which represents either a state-field pathe expression or a result variable, and creates the StateObject.

Parameters:

jpqlFragment - The portion of the query representing a state-field path expression or result variable

removeOrdering

public void removeOrdering()

Removes the ordering if it's specified, otherwise do nothing.

setExpression

public void setExpression(OrderByItem expression)

Keeps a reference of the parsed object object, which should only be done when this object is instantiated during the conversion of a parsed JPQL query into StateObjects.

Parameters:

expression - The parsed object representing an order by item

setOrdering

public void setOrdering(OrderByItem.Ordering ordering)

Sets the enum constant representing the ordering type.

Parameters:

ordering - The constant representing the ordering, in the case the ordering was not parsed, then OrderByItem.Ordering.DEFAULT should be used

setStateObject

public void setStateObject(StateObject stateObject)

Sets the StateObject representing the value used for ordering.

Parameters:

stateObject - The StateObject representing the value used for ordering

toTextInternal

protected void toTextInternal(java.lang.Appendable writer)
                       throws java.io.IOException

Prints out a string representation of this StateObject, which should not be used to define a true string representation of a JPQL query but should be used for debugging purposes.

Specified by:

toTextInternal in class AbstractStateObject

Parameters:

writer - The writer used to print out the string representation

Throws:

java.io.IOException - This should never happens, it is only required because Appendable is used instead of any concrete class