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

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

All Implemented Interfaces:

StateObject

public class JoinStateObject
extends AbstractStateObject

A JOIN enables the fetching of an association as a side effect of the execution of a query. A JOIN is specified over an entity and its related entities.

BNF: join ::= join_spec join_association_path_expression [AS] identification_variable

A JOIN FETCH enables the fetching of an association as a side effect of the execution of a query. A JOIN FETCH is specified over an entity and its related entities.

BNF: fetch_join ::= join_spec FETCH join_association_path_expression

Version:

2.4

See Also:

Join

Author:

Pascal Filion

Since:

2.4

Field Summary

static java.lang.String	AS_PROPERTY Notifies the visibility of the AS identifier has changed.
static java.lang.String	JOIN_TYPE_PROPERTY Notifies the join type property has changed.

Constructor Summary

JoinStateObject(AbstractIdentificationVariableDeclarationStateObject parent, java.lang.String joinType)
Creates a new JoinStateObject.

JoinStateObject(AbstractIdentificationVariableDeclarationStateObject parent, java.lang.String joinType, boolean as)
Creates a new JoinStateObject.

Method Summary

void	accept(StateObjectVisitor visitor) Visits this StateObject by the given visitor.
JoinStateObject	addAs() Makes sure the AS identifier is specified.
protected void	addChildren(java.util.List<StateObject> children) Adds the children of this StateObject to the given list.
void	addJoinAssociationPaths(java.util.List<java.lang.String> paths) Adds the given segments to the end of the join association path expression.
Join	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	getIdentificationVariable() Returns the name of the identification variable that defines the join association path.
IdentificationVariableStateObject	getIdentificationVariableStateObject() Returns the state object holding the identification variable.
StateObject	getJoinAssociationIdentificationVariable() Returns the StateObject representing the identification variable that starts the path expression, which can be a sample identification variable, a map value, map key or map entry expression.
CollectionValuedPathExpressionStateObject	getJoinAssociationPathStateObject() Returns the CollectionValuedPathExpressionStateObject representing the join association path.
java.lang.String	getJoinType() Returns the joining type.
AbstractIdentificationVariableDeclarationStateObject	getParent() Returns the parent of this StateObject.
boolean	hasAs() Determines whether the AS identifier is used or not.
boolean	hasFetch() Determines whether the identifier FETCH was parsed.
boolean	hasIdentificationVariable() Determines whether the identification variable has been defined.
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<java.lang.String>	joinAssociationPaths() Returns the segments in the state field path in order.
int	joinAssociationPathSize() Returns the number of segments in the path expression.
void	removeNot() Makes sure the AS identifier is not specified.
void	setAs(boolean as) Sets whether the AS identifier is used or not.
void	setExpression(Join 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	setIdentificationVariable(java.lang.String identificationVariable) Sets the name of the identification variable that defines the join association path.
void	setJoinAssociationIdentificationVariable(StateObject identificationVariable) Sets the StateObject representing the identification variable that starts the path expression, which can be a sample identification variable, a map value, map key or map entry expression.
void	setJoinAssociationPath(java.lang.String path) Changes the path expression with the list of segments, the identification variable will also be updated with the first segment.
void	setJoinAssociationPaths(java.util.ListIterator<java.lang.String> paths) Changes the path expression with the list of segments, the identification variable will also be updated with the first segment.
void	setJoinAssociationPaths(java.lang.String[] paths) Changes the path expression with the list of segments, the identification variable will also be updated with the first segment.
void	setJoinType(java.lang.String joinType) Sets the joining type.
void	toggleAs() Toggles the usage of the AS identifier.
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.
protected void	validateJoinType(java.lang.String joinType) Validates the given join type.

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

Field Detail

AS_PROPERTY

public static final java.lang.String AS_PROPERTY

Notifies the visibility of the AS identifier has changed.

See Also:

Constant Field Values

JOIN_TYPE_PROPERTY

public static final java.lang.String JOIN_TYPE_PROPERTY

Notifies the join type property has changed.

See Also:

Constant Field Values

Constructor Detail

JoinStateObject

public JoinStateObject(AbstractIdentificationVariableDeclarationStateObject parent,
                       java.lang.String joinType)

Creates a new JoinStateObject.

Parameters:

parent - The parent of this state object

joinType - One of the joining types

JoinStateObject

public JoinStateObject(AbstractIdentificationVariableDeclarationStateObject parent,
                       java.lang.String joinType,
                       boolean as)

Creates a new JoinStateObject.

Parameters:

parent - The parent of this state object

joinType - One of the joining types

as - Determine whether the AS identifier is used or not

Method Detail

accept

public void accept(StateObjectVisitor visitor)

Visits this StateObject by the given visitor.

Parameters:

visitor - The visitor to visit this object

addAs

public JoinStateObject addAs()

Makes sure the AS identifier is specified.

Returns:

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

addJoinAssociationPaths

public void addJoinAssociationPaths(java.util.List<java.lang.String> paths)

Adds the given segments to the end of the join association path expression. The identification variable will not be affected.

Parameters:

paths - The new path expression

getExpression

public Join 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)

getIdentificationVariable

public java.lang.String getIdentificationVariable()

Returns the name of the identification variable that defines the join association path.

Returns:

The variable defining the join association path

getIdentificationVariableStateObject

public IdentificationVariableStateObject getIdentificationVariableStateObject()

Returns the state object holding the identification variable.

Returns:

The portion of the joining expression representing the identification variable

getJoinAssociationIdentificationVariable

public StateObject getJoinAssociationIdentificationVariable()

Returns the StateObject representing the identification variable that starts the path expression, which can be a sample identification variable, a map value, map key or map entry expression.

Returns:

The root of the path expression

getJoinAssociationPathStateObject

public CollectionValuedPathExpressionStateObject getJoinAssociationPathStateObject()

Returns the CollectionValuedPathExpressionStateObject representing the join association path.

Returns:

The state object representing the join association path

getJoinType

public java.lang.String getJoinType()

Returns the joining type.

Returns:

The joining type of this joining expression

getParent

public AbstractIdentificationVariableDeclarationStateObject 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

hasAs

public boolean hasAs()

Determines whether the AS identifier is used or not.

Returns:

true if the AS identifier is part of the expression; false otherwise

hasFetch

public boolean hasFetch()

Determines whether the identifier FETCH was parsed.

Returns:

true if the identifier FETCH was parsed; false otherwise

hasIdentificationVariable

public boolean hasIdentificationVariable()

Determines whether the identification variable has been defined.

Returns:

true if the identification has been defined; 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

joinAssociationPaths

public IterableListIterator<java.lang.String> joinAssociationPaths()

Returns the segments in the state field path in order.

Returns:

An Iterator over the segments of the state field path

joinAssociationPathSize

public int joinAssociationPathSize()

Returns the number of segments in the path expression.

Returns:

The number of segments

removeNot

public void removeNot()

Makes sure the AS identifier is not specified.

setAs

public void setAs(boolean as)

Sets whether the AS identifier is used or not.

Parameters:

as - true if the AS identifier is part of the expression; false otherwise

setExpression

public void setExpression(Join 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 JOIN expression

setIdentificationVariable

public void setIdentificationVariable(java.lang.String identificationVariable)

Sets the name of the identification variable that defines the join association path.

Parameters:

identificationVariable - The new variable defining the join association path

setJoinAssociationIdentificationVariable

public void setJoinAssociationIdentificationVariable(StateObject identificationVariable)

Sets the StateObject representing the identification variable that starts the path expression, which can be a sample identification variable, a map value, map key or map entry expression.

Parameters:

identificationVariable - The root of the path expression

setJoinAssociationPath

public void setJoinAssociationPath(java.lang.String path)

Changes the path expression with the list of segments, the identification variable will also be updated with the first segment.

Parameters:

path - The new path expression

setJoinAssociationPaths

public void setJoinAssociationPaths(java.util.ListIterator<java.lang.String> paths)

Changes the path expression with the list of segments, the identification variable will also be updated with the first segment.

Parameters:

paths - The new path expression

setJoinAssociationPaths

public void setJoinAssociationPaths(java.lang.String[] paths)

Changes the path expression with the list of segments, the identification variable will also be updated with the first segment.

Parameters:

paths - The new path expression

setJoinType

public void setJoinType(java.lang.String joinType)

Sets the joining type.

Parameters:

joinType - One of the joining types

toggleAs

public void toggleAs()

Toggles the usage of the AS identifier.

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

validateJoinType

protected void validateJoinType(java.lang.String joinType)

Validates the given join type.

Parameters:

joinType - One of the possible joining types