org.eclipse.persistence.jpa.jpql.model.query
Class CoalesceExpressionStateObject

java.lang.Object
  org.eclipse.persistence.jpa.jpql.model.query.AbstractStateObject
      org.eclipse.persistence.jpa.jpql.model.query.AbstractEncapsulatedExpressionStateObject
          org.eclipse.persistence.jpa.jpql.model.query.CoalesceExpressionStateObject

All Implemented Interfaces:

ListHolderStateObject<StateObject>, StateObject

public class CoalesceExpressionStateObject
extends AbstractEncapsulatedExpressionStateObject
implements ListHolderStateObject<StateObject>

A COALESCE expression returns null if all its arguments evaluate to null, and the value of the first non-null argument otherwise.

The return type is the type returned by the arguments if they are all of the same type, otherwise it is undetermined.

BNF: coalesce_expression::= COALESCE(scalar_expression {, scalar_expression}+)

Version:

2.4

See Also:

CoalesceExpression

Author:

Pascal Filion

Since:

2.4

Field Summary

static java.lang.String

STATE_OBJECTS_LIST Notifies the content of the state object list has changed.

Constructor Summary

CoalesceExpressionStateObject(StateObject parent)
Creates a new CoalesceExpressionStateObject.

CoalesceExpressionStateObject(StateObject parent, java.util.List<StateObject> items)
Creates a new CoalesceExpressionStateObject.

CoalesceExpressionStateObject(StateObject parent, StateObject... items)
Creates a new CoalesceExpressionStateObject.

CoalesceExpressionStateObject(StateObject parent, java.lang.String... items)
Creates a new CoalesceExpressionStateObject.

Method Summary

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.
<S extends StateObject> S	addItem(S item) Adds the given StateObject as a child of this one.
void	addItems(java.util.List<? extends StateObject> items) Adds the given list of StateObjects as children of this one.
void	addListChangeListener(java.lang.String listName, IListChangeListener<StateObject> listener) Registers the given IListChangeListener for the specified list.
protected boolean	areChildrenEquivalent(CoalesceExpressionStateObject 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.
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.
CoalesceExpression	getExpression() Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
java.lang.String	getIdentifier() Returns the JPQL identifier of the expression represented by this AbstractSingleEncapsulatedExpressionStateObject.
StateObject	getItem(int index) Returns the StateObject at the given positions from the list
boolean	hasItems() Determines whether this StateObject has any children.
protected void	initialize() Initializes this state object.
boolean	isEquivalent(StateObject stateObject) Determines whether the given StateObject is equivalent to this one, i.e. the information of both StateObject is the same.
IterableListIterator<StateObject>	items() Returns an IterableListIterator 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	parseItem(java.lang.String jpqlFragment) Parses the given JPQL fragment, which represents a single encapsulated expression, and creates the StateObject.
protected void	parseItemInternal(java.lang.String... items) Parses the given list of JPQL fragments, which represents each of the encapsulated expressions, and creates the StateObjects.
void	parseItems(java.util.ListIterator<java.lang.String> items) Parses the given JPQL fragments, which represent individual expression, and creates the StateObjects.
void	parseItems(java.lang.String... items) Parses the given JPQL fragments, which represent individual expression, and creates the StateObjects.
void	removeItem(StateObject item) Removes the given StateObject from the list of children.
void	removeItems(java.util.Collection<StateObject> items) Removes the given StateObject from the list of children.
void	removeListChangeListener(java.lang.String listName, IListChangeListener<StateObject> listener) Unregisters the given IListChangeListener that was registered for the specified list.
void	setExpression(CoalesceExpression 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.
protected void	toTextEncapsulatedExpression(java.lang.Appendable writer) Prints out a string representation of this encapsulated information, 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.model.query.AbstractEncapsulatedExpressionStateObject

toTextInternal

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

acceptUnknownVisitor, acceptUnknownVisitor, addProblems, addPropertyChangeListener, areEquivalent, buildProblem, buildProblem, buildStateObject, buildStateObjects, checkParent, children, decorate, equals, findIdentificationVariable, firePropertyChanged, getChangeSupport, getDeclaration, getDecorator, getGrammar, getManagedTypeProvider, getParent, 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.model.query.StateObject

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

Field Detail

STATE_OBJECTS_LIST

public static final java.lang.String STATE_OBJECTS_LIST

Notifies the content of the state object list has changed.

See Also:

Constant Field Values

Constructor Detail

CoalesceExpressionStateObject

public CoalesceExpressionStateObject(StateObject parent)

Creates a new CoalesceExpressionStateObject.

Parameters:

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

Throws:

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

CoalesceExpressionStateObject

public CoalesceExpressionStateObject(StateObject parent,
                                     java.util.List<StateObject> items)

Creates a new CoalesceExpressionStateObject.

Parameters:

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

items - The list of StateObjects representing the encapsulated expressions

Throws:

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

CoalesceExpressionStateObject

public CoalesceExpressionStateObject(StateObject parent,
                                     StateObject... items)

Creates a new CoalesceExpressionStateObject.

Parameters:

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

items - The list of StateObjects representing the encapsulated expressions

Throws:

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

CoalesceExpressionStateObject

public CoalesceExpressionStateObject(StateObject parent,
                                     java.lang.String... items)

Creates a new CoalesceExpressionStateObject.

Parameters:

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

items - The list of expression to parse into their StateObject

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.

Specified by:

accept in interface StateObject

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

addItem

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

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

addItems

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

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(java.lang.String listName,
                                  IListChangeListener<StateObject> listener)

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(CoalesceExpressionStateObject 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)

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)

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

getExpression

public CoalesceExpression 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 AbstractEncapsulatedExpressionStateObject

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)

getIdentifier

public java.lang.String getIdentifier()

Returns the JPQL identifier of the expression represented by this AbstractSingleEncapsulatedExpressionStateObject.

Specified by:

getIdentifier in class AbstractEncapsulatedExpressionStateObject

Returns:

The JPQL identifier that is shown before the left parenthesis

getItem

public StateObject getItem(int index)

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

hasItems

public boolean hasItems()

Determines whether this StateObject has any children.

Specified by:

hasItems in interface ListHolderStateObject<StateObject>

Returns:

true if this StateObject has children; false otherwise

initialize

protected void initialize()

Initializes this state object.

Overrides:

initialize in class AbstractStateObject

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

items

public IterableListIterator<StateObject> items()

Returns an IterableListIterator over the children.

Specified by:

items in interface ListHolderStateObject<StateObject>

Returns:

An IterableListIterator that is iterating over the children

itemsSize

public int itemsSize()

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)

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)

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

parseItem

public void parseItem(java.lang.String jpqlFragment)

Parses the given JPQL fragment, which represents a single encapsulated expression, and creates the StateObject.

Parameters:

jpqlFragment - The portion of the query representing a single encapsulated expression

parseItemInternal

protected void parseItemInternal(java.lang.String... items)

Parses the given list of JPQL fragments, which represents each of the encapsulated expressions, and creates the StateObjects.

Parameters:

items - The list of expression to parse into their StateObject

parseItems

public void parseItems(java.util.ListIterator<java.lang.String> items)

Parses the given JPQL fragments, which represent individual expression, and creates the StateObjects.

Parameters:

items - The portion of the query representing a single encapsulated expression

parseItems

public void parseItems(java.lang.String... items)

Parses the given JPQL fragments, which represent individual expression, and creates the StateObjects.

Parameters:

items - The portion of the query representing a single encapsulated expression

removeItem

public void removeItem(StateObject item)

Removes the given StateObject from the list of children.

Specified by:

removeItem in interface ListHolderStateObject<StateObject>

Parameters:

item - The child StateObject to not longer be a child

removeItems

public void removeItems(java.util.Collection<StateObject> items)

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(java.lang.String listName,
                                     IListChangeListener<StateObject> listener)

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(CoalesceExpression 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 CASE expression

toTextEncapsulatedExpression

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

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

Specified by:

toTextEncapsulatedExpression in class AbstractEncapsulatedExpressionStateObject

Parameters:

writer - The writer used to print out the string representation of the encapsulated information

Throws:

java.io.IOException - This should never happens, only required because Appendable is used instead of StringBuilder for instance