Module org.eclipse.persistence.jpa.jpql

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

Class SelectClauseStateObject

java.lang.Object

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

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

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

All Implemented Interfaces:

ListHolderStateObject<StateObject>, StateObject

public class SelectClauseStateObject
extends AbstractSelectClauseStateObject
implements ListHolderStateObject<StateObject>

The SELECT statement queries data from entities, which determines the type of the objects or values to be selected.

BNF: select_clause ::= SELECT [DISTINCT] select_expression {, select_expression}*
     select_expression ::= single_valued_path_expression |
                           aggregate_expression |
                           identification_variable |
                           OBJECT(identification_variable) |
                           constructor_expression

Since:

2.4

Version:

2.4

See Also:

• SelectStatementStateObject
• SelectClause

Field Summary

Fields

Modifier and Type	Field	Description
static final String	SELECT_ITEMS_LIST	A constant used to notify the list of select expressions has changed.

Fields inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractSelectClauseStateObject

DISTINCT_PROPERTY

Constructor Summary

Constructors

Constructor	Description
SelectClauseStateObject(SelectStatementStateObject parent)	Creates a new SelectClauseStateObject.

Method Summary

Modifier and Type	Method	Description
void	accept(StateObjectVisitor visitor)	Visits this StateObject by the given visitor.
protected void	addChildren(List<StateObject> children)	Adds the children of this StateObject to the given list.
StateObject	addItem(String jpqlFragment)	Adds the given path as a select item, which can either be an identification variable or a state-field path expression.
ResultVariableStateObject	addItem(String jpqlFragment, String resultVariable)	Adds the given expression as a select item.
ResultVariableStateObject	addItem(StateObject stateObject, String resultVariable)	Adds the given StateObject as a select item.
<S extends StateObject> S	addItem(S item)	Adds the given StateObject as a child of this one.
ResultVariableStateObject	addItemAs(String jpqlFragment, String resultVariable)	Adds the given JPQL fragment as a select item.
ResultVariableStateObject	addItemAs(StateObject stateObject, String resultVariable)	Adds the given StateObject as a select item.
void	addItems(List<? extends StateObject> items)	Adds the given list of StateObjects as children of this one.
void	addListChangeListener(String listName, IListChangeListener<StateObject> listener)	Registers the given IListChangeListener for the specified list.
protected boolean	areChildrenEquivalent(SelectClauseStateObject stateObject)	Determines whether the children of this StateObject are equivalent to the children of the given one, i.e.
boolean	canMoveDown(StateObject item)	Determines whether the given StateObject can be moved down by one position in the list owned by its parent.
boolean	canMoveUp(StateObject item)	Determines whether the given StateObject can be moved up by one position in the list owned by its parent.
ISelectExpressionStateObjectBuilder	getBuilder()	Creates and returns a new ISelectExpressionStateObjectBuilder that can be used to programmatically create a single select expression and once the expression is complete, ISelectExpressionStateObjectBuilder.commit() will push the StateObject representation of that expression as this clause's select expression.
SelectClause	getExpression()	Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
FromClauseStateObject	getFromClause()	Returns the AbstractFromClauseStateObject representing the FROM clause.
StateObject	getItem(int index)	Returns the StateObject at the given positions from the list
SelectStatementStateObject	getParent()	Returns the parent of this StateObject.
boolean	hasItems()	Determines whether this StateObject has any children.
boolean	hasSelectItem()	Determines whether this SELECT clause has a select item defined (only one can be set for a subquery's SELECT clause and many for a top-level query).
protected void	initialize()	Initializes this state object.
boolean	isEquivalent(StateObject stateObject)	Determines whether the given StateObject is equivalent to this one, i.e.
ListIterable<StateObject>	items()	Returns an ListIterable over the children.
int	itemsSize()	Returns the number of children this list holder has.
StateObject	moveDown(StateObject item)	Moves the given StateObject down by one position in the list owned by its parent.
StateObject	moveUp(StateObject item)	Moves the given StateObject up by one position in the list owned by its parent.
void	parse(String jpqlFragment)	Parses the given JPQL fragment and create the select item.
void	removeItem(StateObject stateObject)	Removes the given StateObject from the list of children.
void	removeItems(Collection<StateObject> items)	Removes the given StateObject from the list of children.
void	removeListChangeListener(String listName, IListChangeListener<StateObject> listener)	Unregisters the given IListChangeListener that was registered for the specified list.
void	setExpression(SelectClause 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	setItems(List<StateObject> stateObjects)	Sets the select expression to be those contained on the given collection.
protected void	toTextInternal(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.AbstractSelectClauseStateObject

hasDistinct, setDistinct, toggleDistinct

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, 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

Methods inherited from interface org.eclipse.persistence.jpa.jpql.tools.model.query.StateObject

addPropertyChangeListener, children, decorate, findIdentificationVariable, getDeclaration, getDecorator, getGrammar, getManagedTypeProvider, getQueryBuilder, getRoot, isDecorated, removePropertyChangeListener, setParent, toString, toText

Field Details

SELECT_ITEMS_LIST

public static final String SELECT_ITEMS_LIST

A constant used to notify the list of select expressions has changed.

See Also:

• Constant Field Values

Constructor Details

SelectClauseStateObject

public SelectClauseStateObject(SelectStatementStateObject parent)

Creates a new SelectClauseStateObject.

Parameters:

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

Throws:

NullPointerException - The given parent cannot be null

Method Details

accept

public void accept(StateObjectVisitor visitor)

Description copied from interface: StateObject

Visits this StateObject by the given visitor.

Specified by:

accept in interface StateObject

Parameters:

visitor - The visitor to visit this object

addChildren

protected void addChildren(List<StateObject> children)

Description copied from class: AbstractStateObject

Adds the children of this StateObject to the given list.

Overrides:

addChildren in class AbstractStateObject

Parameters:

children - The list used to store the children

addItem

public ResultVariableStateObject addItem(StateObject stateObject,
 String resultVariable)

Adds the given StateObject as a select item.

Parameters:

stateObject - The StateObject representing the select expression

resultVariable - The result variable identifying the select expression

Returns:

The newly created ResultVariableStateObject

addItem

public StateObject addItem(String jpqlFragment)

Adds the given path as a select item, which can either be an identification variable or a state-field path expression.

Parameters:

jpqlFragment - The select expression to parse as a select item

Returns:

The StateObject encapsulating the given path

addItem

public ResultVariableStateObject addItem(String jpqlFragment,
 String resultVariable)

Adds the given expression as a select item.

Parameters:

jpqlFragment - The select expression to parse as a select item

resultVariable - The result variable identifying the select expression

Returns:

The newly created ResultVariableStateObject

addItem

public <S extends StateObject> S addItem(S item)

Description copied from interface: ListHolderStateObject

Adds the given StateObject as a child of this one.

Specified by:

addItem in interface ListHolderStateObject<StateObject>

Parameters:

item - The child StateObject to become a child of this one return The given item

addItemAs

public ResultVariableStateObject addItemAs(StateObject stateObject,
 String resultVariable)

Adds the given StateObject as a select item.

Parameters:

stateObject - The StateObject representing the select expression

resultVariable - The result variable identifying the select expression

Returns:

The newly created ResultVariableStateObject

addItemAs

public ResultVariableStateObject addItemAs(String jpqlFragment,
 String resultVariable)

Adds the given JPQL fragment as a select item.

Parameters:

jpqlFragment - The portion of a JPQL query that represents a select expression

resultVariable - The result variable identifying the select expression

Returns:

The newly created ResultVariableStateObject

addItems

public void addItems(List<? extends StateObject> items)

Description copied from interface: ListHolderStateObject

Adds the given list of StateObjects as children of this one.

Specified by:

addItems in interface ListHolderStateObject<StateObject>

Parameters:

items - The StateObjects to become children of this one

addListChangeListener

public void addListChangeListener(String listName,
 IListChangeListener<StateObject> listener)

Description copied from interface: ListHolderStateObject

Registers the given IListChangeListener for the specified list. The listener will be notified only when items are added, removed, moved from the list.

Specified by:

addListChangeListener in interface ListHolderStateObject<StateObject>

Parameters:

listName - The name of the list for which the listener will be notified when the content of the list has changed

listener - The listener to be notified upon changes

areChildrenEquivalent

protected boolean areChildrenEquivalent(SelectClauseStateObject stateObject)

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

Parameters:

stateObject - The StateObject to compare its children to this one's children

Returns:

true if both have equivalent children; false otherwise

canMoveDown

public boolean canMoveDown(StateObject item)

Description copied from interface: ListHolderStateObject

Determines whether the given StateObject can be moved down by one position in the list owned by its parent.

Specified by:

canMoveDown in interface ListHolderStateObject<StateObject>

Parameters:

item - The StateObject that could potentially be moved down

Returns:

true if the object can be moved down by one unit; false otherwise

canMoveUp

public boolean canMoveUp(StateObject item)

Description copied from interface: ListHolderStateObject

Determines whether the given StateObject can be moved up by one position in the list owned by its parent.

Specified by:

canMoveUp in interface ListHolderStateObject<StateObject>

Parameters:

item - The StateObject that could potentially be moved up

Returns:

true if the object can be moved up by one unit; false otherwise

getBuilder

public ISelectExpressionStateObjectBuilder getBuilder()

Creates and returns a new ISelectExpressionStateObjectBuilder that can be used to programmatically create a single select expression and once the expression is complete, ISelectExpressionStateObjectBuilder.commit() will push the StateObject representation of that expression as this clause's select expression.

Returns:

A new builder that can be used to quickly create a select expression

getExpression

public SelectClause getExpression()

Description copied from interface: StateObject

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 AbstractSelectClauseStateObject

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)

getFromClause

public FromClauseStateObject getFromClause()

Description copied from class: AbstractSelectClauseStateObject

Returns the AbstractFromClauseStateObject representing the FROM clause.

Overrides:

getFromClause in class AbstractSelectClauseStateObject

Returns:

The state object representing the FROM clause

getItem

public StateObject getItem(int index)

Description copied from interface: ListHolderStateObject

Returns the StateObject at the given positions from the list

Specified by:

getItem in interface ListHolderStateObject<StateObject>

Parameters:

index - The position of the StateObject to retrieve

Returns:

The StateObject at the given position

getParent

public SelectStatementStateObject getParent()

Description copied from interface: StateObject

Returns the parent of this StateObject.

Specified by:

getParent in interface StateObject

Overrides:

getParent in class AbstractSelectClauseStateObject

Returns:

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

hasItems

public boolean hasItems()

Description copied from interface: ListHolderStateObject

Determines whether this StateObject has any children.

Specified by:

hasItems in interface ListHolderStateObject<StateObject>

Returns:

true if this StateObject has children; false otherwise

hasSelectItem

public boolean hasSelectItem()

Description copied from class: AbstractSelectClauseStateObject

Determines whether this SELECT clause has a select item defined (only one can be set for a subquery's SELECT clause and many for a top-level query).

Specified by:

hasSelectItem in class AbstractSelectClauseStateObject

Returns:

true if this state object has children; false otherwise

initialize

protected void initialize()

Description copied from class: AbstractStateObject

Initializes this state object.

Overrides:

initialize in class AbstractStateObject

isEquivalent

public boolean isEquivalent(StateObject stateObject)

Description copied from interface: 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 AbstractSelectClauseStateObject

Parameters:

stateObject - The StateObject to compare its content to this one

Returns:

true if both object are equivalent; false otherwise

items

public ListIterable<StateObject> items()

Description copied from interface: ListHolderStateObject

Returns an ListIterable over the children.

Specified by:

items in interface ListHolderStateObject<StateObject>

Returns:

An ListIterable that is iterating over the children

itemsSize

public int itemsSize()

Description copied from interface: ListHolderStateObject

Returns the number of children this list holder has.

Specified by:

itemsSize in interface ListHolderStateObject<StateObject>

Returns:

The count of StateObjects that are children of this one

moveDown

public StateObject moveDown(StateObject item)

Description copied from interface: ListHolderStateObject

Moves the given StateObject down by one position in the list owned by its parent.

Specified by:

moveDown in interface ListHolderStateObject<StateObject>

Parameters:

item - The StateObject to move down in the list

Returns:

The given item

moveUp

public StateObject moveUp(StateObject item)

Description copied from interface: ListHolderStateObject

Moves the given StateObject up by one position in the list owned by its parent.

Specified by:

moveUp in interface ListHolderStateObject<StateObject>

Parameters:

item - The StateObject to move up in the list

Returns:

The given item

parse

public void parse(String jpqlFragment)

Description copied from class: AbstractSelectClauseStateObject

Parses the given JPQL fragment and create the select item. For the top-level query, the fragment can contain several select items but for a subquery, it can represent only one.

Specified by:

parse in class AbstractSelectClauseStateObject

Parameters:

jpqlFragment - The portion of the query representing one or several select items

removeItem

public void removeItem(StateObject stateObject)

Description copied from interface: ListHolderStateObject

Removes the given StateObject from the list of children.

Specified by:

removeItem in interface ListHolderStateObject<StateObject>

Parameters:

stateObject - The child StateObject to not longer be a child

removeItems

public void removeItems(Collection<StateObject> items)

Description copied from interface: ListHolderStateObject

Removes the given StateObject from the list of children.

Specified by:

removeItems in interface ListHolderStateObject<StateObject>

Parameters:

items - The StateObjects to remove from this one

removeListChangeListener

public void removeListChangeListener(String listName,
 IListChangeListener<StateObject> listener)

Description copied from interface: ListHolderStateObject

Unregisters the given IListChangeListener that was registered for the specified list. The listener will no longer be notified only when items are added, removed, moved from the list.

Specified by:

removeListChangeListener in interface ListHolderStateObject<StateObject>

Parameters:

listName - The name of the list for which the listener was registered

listener - The listener to unregister

setExpression

public void setExpression(SelectClause 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 a SELECT clause

setItems

public void setItems(List<StateObject> stateObjects)

Sets the select expression to be those contained on the given collection. If any select items were already set, they will be removed.

Parameters:

stateObjects - The new select expressions

toTextInternal

protected void toTextInternal(Appendable writer)
                       throws IOException

Description copied from class: AbstractStateObject

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:

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