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

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

All Implemented Interfaces:

StateObject

public class SimpleSelectClauseStateObject
extends AbstractSelectClauseStateObject

The SELECT statement queries data from entities. This version simply does not handle OBJECT and NEW identifiers. It is used from within another expression.

BNF: simple_select_clause ::= SELECT [DISTINCT] simple_select_expression

Version:

2.4

See Also:

SimpleSelectClause

Author:

Pascal Filion

Since:

2.4

Field Summary

static java.lang.String

SELECT_ITEM_PROPERTY Notifies the select expression property has changed.

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

DISTINCT_PROPERTY

Constructor Summary

SimpleSelectClauseStateObject(SimpleSelectStatementStateObject parent)
Creates a new SubQuerySelectClauseStateObject.

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.
ISimpleSelectExpressionStateObjectBuilder	getBuilder() Creates and returns a new ISimpleSelectExpressionStateObjectBuilder that can be used to programmatically create a single select expression and once the expression is complete, ISimpleSelectExpressionStateObjectBuilder.commit() will push the StateObject representation of that expression as this clause's select expression.
SimpleSelectClause	getExpression() Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
SimpleFromClauseStateObject	getFromClause() Returns the AbstractFromClauseStateObject representing the FROM clause.
SimpleSelectStatementStateObject	getParent() Returns the parent of this StateObject.
StateObject	getSelectItem() Returns
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).
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 and create the select item.
void	setExpression(SimpleSelectClause 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	setSelectItem(StateObject stateObject) Sets the given StateObject as this clause's select item.
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, 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

SELECT_ITEM_PROPERTY

public static final java.lang.String SELECT_ITEM_PROPERTY

Notifies the select expression property has changed.

See Also:

Constant Field Values

Constructor Detail

SimpleSelectClauseStateObject

public SimpleSelectClauseStateObject(SimpleSelectStatementStateObject parent)

Creates a new SubQuerySelectClauseStateObject.

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

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

getBuilder

public ISimpleSelectExpressionStateObjectBuilder getBuilder()

Creates and returns a new ISimpleSelectExpressionStateObjectBuilder that can be used to programmatically create a single select expression and once the expression is complete, ISimpleSelectExpressionStateObjectBuilder.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 SimpleSelectClause 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 SimpleFromClauseStateObject getFromClause()

Returns the AbstractFromClauseStateObject representing the FROM clause.

Overrides:

getFromClause in class AbstractSelectClauseStateObject

Returns:

The state object representing the FROM clause

getParent

public SimpleSelectStatementStateObject 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

getSelectItem

public StateObject getSelectItem()

Returns

Returns:

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

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

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

setExpression

public void setExpression(SimpleSelectClause 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 subquery SELECT

setSelectItem

public void setSelectItem(StateObject stateObject)

Sets the given StateObject as this clause's select item.

Parameters:

stateObject - The StateObject representing the single select item

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