java.lang.Object
- org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
- - org.eclipse.persistence.jpa.jpql.parser.Join

All Implemented Interfaces:

Expression
```
public final class Join
extends AbstractExpression
```
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

EclipseLink 2.4
BNF: join_spec { abstract_schema_name | join_association_path_expression } [AS] identification_variable [join_condition]

Since:

2.3

Version:

2.5

Author:

Pascal Filion

Field Summary
- Fields inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
  COMMA, DOT, DOUBLE_QUOTE, LEFT_CURLY_BRACKET, LEFT_PARENTHESIS, NOT_DEFINED, RIGHT_CURLY_BRACKET, RIGHT_PARENTHESIS, SINGLE_QUOTE, SPACE, UNDERSCORE
- Fields inherited from interface org.eclipse.persistence.jpa.jpql.parser.Expression
  ABS, ALL, AND, ANY, AS, AS_OF, ASC, AVG, BETWEEN, BIT_LENGTH, BOTH, CASE, CAST, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, COLUMN, CONCAT, CONNECT_BY, COUNT, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, DELETE, DELETE_FROM, DESC, DIFFERENT, DISTINCT, DIVISION, ELSE, EMPTY, END, ENTRY, EQUAL, ESCAPE, EXCEPT, EXISTS, EXTRACT, FALSE, FETCH, FIRST, FROM, FUNC, FUNCTION, GREATER_THAN, GREATER_THAN_OR_EQUAL, GROUP_BY, HAVING, IN, INDEX, INNER, INNER_JOIN, INNER_JOIN_FETCH, INTERSECT, IS, IS_EMPTY, IS_NOT_EMPTY, IS_NOT_NULL, IS_NULL, JOIN, JOIN_FETCH, KEY, LAST, LEADING, LEFT, LEFT_JOIN, LEFT_JOIN_FETCH, LEFT_OUTER_JOIN, LEFT_OUTER_JOIN_FETCH, LENGTH, LIKE, LOCATE, LOWER, LOWER_THAN, LOWER_THAN_OR_EQUAL, MAX, MEMBER, MEMBER_OF, MIN, MINUS, MOD, MULTIPLICATION, NAMED_PARAMETER, NEW, NOT, NOT_BETWEEN, NOT_EQUAL, NOT_EXISTS, NOT_IN, NOT_LIKE, NOT_MEMBER, NOT_MEMBER_OF, NULL, NULLIF, NULLS, NULLS_FIRST, NULLS_LAST, OBJECT, OF, ON, OPERATOR, OR, ORDER_BY, ORDER_SIBLINGS_BY, OUTER, PLUS, POSITION, POSITIONAL_PARAMETER, QUOTE, REGEXP, SCN, SELECT, SET, SIZE, SOME, SQL, SQRT, START_WITH, SUBSTRING, SUM, TABLE, THEN, TIMESTAMP, TRAILING, TREAT, TRIM, TRUE, TYPE, UNION, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE

Constructor Summary

Constructors
Constructor Description

Join(AbstractExpression parent, String identifier)
Creates a new Join.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`accept(ExpressionVisitor visitor)`	Visits this `Expression` by the given `visitor`.
`void`	`acceptChildren(ExpressionVisitor visitor)`	Visits the children of this `Expression`.
`JPQLQueryBNF`	`findQueryBNF(Expression expression)`	Retrieves the `JPQLQueryBNF` that represents the fragment of this `Expression` that was used when parsing the given `Expression`.
`String`	`getActualAsIdentifier()`	Returns the actual AS found in the string representation of the JPQL query, which has the actual case that was used.
`String`	`getActualIdentifier()`	Returns the actual identifier found in the string representation of the JPQL query, which has the actual case that was used.
`Expression`	`getIdentificationVariable()`	Returns the `Expression` that represents the identification variable.
`String`	`getIdentifier()`	Returns the identifier this expression represents.
`Expression`	`getJoinAssociationPath()`	Returns the `Expression` that represents the join association path expression.
`Expression`	`getOnClause()`	Returns the `Expression` that represents the ON clause if present.
`JPQLQueryBNF`	`getQueryBNF()`	Returns the BNF of this `Expression`.
`boolean`	`hasAs()`	Determines whether the identifier AS was parsed.
`boolean`	`hasFetch()`	Determines whether the identifier FETCH was parsed.
`boolean`	`hasIdentificationVariable()`	Determines whether the identification variable was parsed.
`boolean`	`hasJoinAssociationPath()`	Determines whether the join association path expression was parsed.
`boolean`	`hasOnClause()`	Determines whether the ON clause was parsed.
`boolean`	`hasSpaceAfterAs()`	Determines whether a whitespace was parsed after AS.
`boolean`	`hasSpaceAfterIdentificationVariable()`	Determines whether a whitespace was parsed before ON.
`boolean`	`hasSpaceAfterJoin()`	Determines whether a whitespace was parsed after JOIN.
`boolean`	`hasSpaceAfterJoinAssociation()`	Determines whether a whitespace was parsed after the join association path expression.
`boolean`	`isLeftJoin()`	Determines whether this `Join` is a left join, i.e.

Methods inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
children, getGrammar, getIdentifierVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, isAncestor, orderedChildren, populatePosition, toActualText, toParsedText, toString

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Join
```
public Join(AbstractExpression parent,
            String identifier)
```
    Creates a new Join.
    
    Parameters:
    
    parent - The parent of this expression
    
    identifier - The full JOIN identifier
- Method Detail
  - accept
```
public void accept(ExpressionVisitor visitor)
```
    Visits this Expression by the given visitor.
    
    Parameters:
    
    visitor - The ExpressionVisitor to visit this object
  - acceptChildren
```
public void acceptChildren(ExpressionVisitor visitor)
```
    Visits the children of this Expression. This method can be used to optimize traversing the children since a new list is not created every time Expression.children() is called.
    This does not traverse the Expression sub-hierarchy, use a subclass of AbstractTraverseChildrenVisitor in order to traverse the entire sub-hierarchy.
    
    Parameters:
    
    visitor - The visitor to visit the children of this object.
  - findQueryBNF
```
public JPQLQueryBNF findQueryBNF(Expression expression)
```
    Retrieves the JPQLQueryBNF that represents the fragment of this Expression that was used when parsing the given Expression.
    
    Specified by:
    
    findQueryBNF in interface Expression
    
    Overrides:
    
    findQueryBNF in class AbstractExpression
    
    Parameters:
    
    expression - The Expression that is a descendant of this one
    
    Returns:
    
    The JPQLQueryBNF that was used to parse the given expression
  - getActualAsIdentifier
```
public String getActualAsIdentifier()
```
    Returns the actual AS found in the string representation of the JPQL query, which has the actual case that was used.
    
    Returns:
    
    The AS identifier that was actually parsed, or an empty string if it was not parsed
  - getActualIdentifier
```
public String getActualIdentifier()
```
    Returns the actual identifier found in the string representation of the JPQL query, which has the actual case that was used.
    
    Returns:
    
    The identifier identifier that was actually parsed
  - getIdentificationVariable
```
public Expression getIdentificationVariable()
```
    Returns the Expression that represents the identification variable.
    
    Returns:
    
    The expression that was parsed representing the identification variable
  - getIdentifier
```
public String getIdentifier()
```
    Returns the identifier this expression represents.
    
    Returns:
    
    Either JOIN, INNER JOIN, LEFT JOIN or LEFT OUTER JOIN. Although it's possible to have an incomplete identifier if the query is not complete
  - getJoinAssociationPath
```
public Expression getJoinAssociationPath()
```
    Returns the Expression that represents the join association path expression.
    
    Returns:
    
    The expression that was parsed representing the join association path expression
  - getOnClause
```
public Expression getOnClause()
```
    Returns the Expression that represents the ON clause if present.
    
    Returns:
    
    The expression that was parsed representing the identification variable
  - getQueryBNF
```
public JPQLQueryBNF getQueryBNF()
```
    Returns the BNF of this Expression.
    
    Returns:
    
    The JPQLQueryBNF, which represents the grammar of this Expression
  - hasAs
```
public boolean hasAs()
```
    Determines whether the identifier AS was parsed.
    
    Returns:
    
    true if the identifier AS was parsed; 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 was parsed.
    
    Returns:
    
    true if the identification variable was parsed; false otherwise
  - hasJoinAssociationPath
```
public boolean hasJoinAssociationPath()
```
    Determines whether the join association path expression was parsed.
    
    Returns:
    
    true if the join association path expression was parsed; false otherwise
  - hasOnClause
```
public boolean hasOnClause()
```
    Determines whether the ON clause was parsed.
    
    Returns:
    
    true if the ON clause was parsed; false otherwise
  - hasSpaceAfterAs
```
public boolean hasSpaceAfterAs()
```
    Determines whether a whitespace was parsed after AS.
    
    Returns:
    
    true if there was a whitespace after AS; false otherwise
  - hasSpaceAfterIdentificationVariable
```
public boolean hasSpaceAfterIdentificationVariable()
```
    Determines whether a whitespace was parsed before ON.
    
    Returns:
    
    true if there was a whitespace before ON; false otherwise
  - hasSpaceAfterJoin
```
public boolean hasSpaceAfterJoin()
```
    Determines whether a whitespace was parsed after JOIN.
    
    Returns:
    
    true if there was a whitespace after JOIN; false otherwise
  - hasSpaceAfterJoinAssociation
```
public boolean hasSpaceAfterJoinAssociation()
```
    Determines whether a whitespace was parsed after the join association path expression.
    
    Returns:
    
    true if there was a whitespace after join association path expression; false otherwise
  - isLeftJoin
```
public boolean isLeftJoin()
```
    Determines whether this Join is a left join, i.e. Expression.LEFT_JOIN, Expression.LEFT_JOIN_FETCH, Expression.LEFT_OUTER_JOIN, Expression.LEFT_OUTER_JOIN_FETCH.
    
    Returns:
    
    true if this Join expression is a Expression.LEFT_JOIN, Expression.LEFT_JOIN_FETCH, Expression.LEFT_OUTER_JOIN, Expression.LEFT_OUTER_JOIN_FETCH; false otherwise

Class Join

Field Summary

Fields inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression

Fields inherited from interface org.eclipse.persistence.jpa.jpql.parser.Expression

Constructor Summary

Method Summary

Methods inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression

Methods inherited from class java.lang.Object

Constructor Detail

Join

Method Detail

accept

acceptChildren

findQueryBNF

getActualAsIdentifier

getActualIdentifier

getIdentificationVariable

getIdentifier

getJoinAssociationPath

getOnClause

getQueryBNF

hasAs

hasFetch

hasIdentificationVariable

hasJoinAssociationPath

hasOnClause

hasSpaceAfterAs

hasSpaceAfterIdentificationVariable

hasSpaceAfterJoin

hasSpaceAfterJoinAssociation

isLeftJoin