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

java.lang.Object
  org.eclipse.persistence.jpa.jpql.model.query.AbstractStateObject
      org.eclipse.persistence.jpa.jpql.model.query.AbstractListHolderStateObject<StateObject>
          org.eclipse.persistence.jpa.jpql.model.query.GroupByClauseStateObject

All Implemented Interfaces:

ListHolderStateObject<StateObject>, StateObject

public class GroupByClauseStateObject
extends AbstractListHolderStateObject<StateObject>

The GROUP BY construct enables the aggregation of values according to the properties of an entity class.

BNF: groupby_clause ::= GROUP BY groupby_item {, groupby_item}*

Version:

2.4

See Also:

GroupByClause

Author:

Pascal Filion

Since:

2.4

Field Summary

static java.lang.String

GROUP_BY_ITEMS_LIST Notify the list of StateObjects representing the GROUP BY items.

Constructor Summary

GroupByClauseStateObject(AbstractSelectStatementStateObject parent)
Creates a new GroupByClauseStateObject.

Method Summary

void	accept(StateObjectVisitor visitor) Visits this StateObject by the given visitor.
StateObject	addGroupByItem(java.lang.String path) Adds the given path as a select item, which can either be an identification variable or a state-field path expression.
GroupByClause	getExpression() Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
AbstractSelectStatementStateObject	getParent() Returns the parent of this StateObject.
boolean	isEquivalent(StateObject stateObject) Determines whether the given StateObject is equivalent to this one, i.e. the information of both StateObject is the same.
protected java.lang.String	listName() Returns the name that is uniquely identifying the list.
void	parse(java.lang.String jpqlFragment) Parses the given JPQL fragment, which will represent the group by items.
void	setExpression(GroupByClause 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	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.AbstractListHolderStateObject

addChildren, addItem, addItems, addListChangeListener, areChildrenEquivalent, canMoveDown, canMoveUp, getItem, hasItems, initialize, items, itemsSize, moveDown, moveUp, removeItem, removeItems, removeListChangeListener, toStringItems

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

GROUP_BY_ITEMS_LIST

public static final java.lang.String GROUP_BY_ITEMS_LIST

Notify the list of StateObjects representing the GROUP BY items.

See Also:

Constant Field Values

Constructor Detail

GroupByClauseStateObject

public GroupByClauseStateObject(AbstractSelectStatementStateObject parent)

Creates a new GroupByClauseStateObject.

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.

Parameters:

visitor - The visitor to visit this object

addGroupByItem

public StateObject addGroupByItem(java.lang.String path)

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

Parameters:

path - Either an identification variable or a state-field path expression

Returns:

The StateObject encapsulating the given path

getExpression

public GroupByClause 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)

getParent

public AbstractSelectStatementStateObject 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

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

listName

protected java.lang.String listName()

Returns the name that is uniquely identifying the list.

Specified by:

listName in class AbstractListHolderStateObject<StateObject>

Returns:

The unique name identifying the list

parse

public void parse(java.lang.String jpqlFragment)

Parses the given JPQL fragment, which will represent the group by items. The fragment cannot start with the GROUP BY.

Parameters:

jpqlFragment - The string representation of the group by items

setExpression

public void setExpression(GroupByClause 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 GROUP BY clause

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