EclipseLink 2.4.2, build 'v20130514-5956486' API Reference

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

java.lang.Object
  extended by org.eclipse.persistence.jpa.jpql.model.query.AbstractStateObject
      extended by org.eclipse.persistence.jpa.jpql.model.query.AbstractSelectClauseStateObject
          extended by org.eclipse.persistence.jpa.jpql.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

Version:
2.4
See Also:
SelectStatementStateObject, SelectClause
Author:
Pascal Filion
Since:
2.4

Field Summary
static java.lang.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.model.query.AbstractSelectClauseStateObject
DISTINCT_PROPERTY
 
Constructor Summary
SelectClauseStateObject(SelectStatementStateObject parent)
          Creates a new SelectClauseStateObject.
 
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.
 ResultVariableStateObject addItem(StateObject stateObject, java.lang.String resultVariable)
          Adds the given StateObject as a select item.
 StateObject addItem(java.lang.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(java.lang.String jpqlFragment, java.lang.String resultVariable)
          Adds the given expression as a select item.
 ResultVariableStateObject addItemAs(StateObject stateObject, java.lang.String resultVariable)
          Adds the given StateObject as a select item.
 ResultVariableStateObject addItemAs(java.lang.String jpqlFragment, java.lang.String resultVariable)
          Adds the given JPQL fragment as a select item.
 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(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.
 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. 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 parse(java.lang.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(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(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(java.util.List<StateObject> stateObjects)
          Sets the select expression to be those contained on the given collection.
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.model.query.AbstractSelectClauseStateObject
hasDistinct, setDistinct, toggleDistinct
 
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, 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, getQueryBuilder, getRoot, isDecorated, removePropertyChangeListener, setParent, toString, toText
 

Field Detail

SELECT_ITEMS_LIST

public static final java.lang.String SELECT_ITEMS_LIST
A constant used to notify the list of select expressions has changed.

See Also:
Constant Field Values
Constructor Detail

SelectClauseStateObject

public SelectClauseStateObject(SelectStatementStateObject parent)
Creates a new SelectClauseStateObject.

Parameters:
parent - The parent of this state object, which cannot be null
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 ResultVariableStateObject addItem(StateObject stateObject,
                                         java.lang.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(java.lang.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(java.lang.String jpqlFragment,
                                         java.lang.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)
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,
                                           java.lang.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(java.lang.String jpqlFragment,
                                           java.lang.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(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(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)
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

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()
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()
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)
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()
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()
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()
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()
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 AbstractSelectClauseStateObject
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

parse

public void parse(java.lang.String jpqlFragment)
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)
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(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(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(java.util.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(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

EclipseLink 2.4.2, build 'v20130514-5956486' API Reference