Class Join
- java.lang.Object
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- org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
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- org.eclipse.persistence.jpa.jpql.parser.Join
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- 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
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Field Summary
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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
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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
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Constructor Summary
Constructors Constructor Description Join(AbstractExpression parent, java.lang.String identifier)
Creates a newJoin
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
accept(ExpressionVisitor visitor)
Visits thisExpression
by the givenvisitor
.void
acceptChildren(ExpressionVisitor visitor)
Visits the children of thisExpression
.JPQLQueryBNF
findQueryBNF(Expression expression)
Retrieves theJPQLQueryBNF
that represents the fragment of thisExpression
that was used when parsing the givenExpression
.java.lang.String
getActualAsIdentifier()
Returns the actual AS found in the string representation of the JPQL query, which has the actual case that was used.java.lang.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 theExpression
that represents the identification variable.java.lang.String
getIdentifier()
Returns the identifier this expression represents.Expression
getJoinAssociationPath()
Returns theExpression
that represents the join association path expression.Expression
getOnClause()
Returns theExpression
that represents the ON clause if present.JPQLQueryBNF
getQueryBNF()
Returns the BNF of thisExpression
.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 thisJoin
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
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Constructor Detail
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Join
public Join(AbstractExpression parent, java.lang.String identifier)
Creates a newJoin
.- Parameters:
parent
- The parent of this expressionidentifier
- The full JOIN identifier
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Method Detail
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accept
public void accept(ExpressionVisitor visitor)
Visits thisExpression
by the givenvisitor
.- Parameters:
visitor
- TheExpressionVisitor
to visit this object
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acceptChildren
public void acceptChildren(ExpressionVisitor visitor)
Visits the children of thisExpression
. This method can be used to optimize traversing the children since a new list is not created every timeExpression.children()
is called.This does not traverse the
Expression
sub-hierarchy, use a subclass ofAbstractTraverseChildrenVisitor
in order to traverse the entire sub-hierarchy.- Parameters:
visitor
- Thevisitor
to visit the children of this object.
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findQueryBNF
public JPQLQueryBNF findQueryBNF(Expression expression)
Retrieves theJPQLQueryBNF
that represents the fragment of thisExpression
that was used when parsing the givenExpression
.- Specified by:
findQueryBNF
in interfaceExpression
- Overrides:
findQueryBNF
in classAbstractExpression
- Parameters:
expression
- TheExpression
that is a descendant of this one- Returns:
- The
JPQLQueryBNF
that was used to parse the given expression
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getActualAsIdentifier
public java.lang.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
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getActualIdentifier
public java.lang.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
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getIdentificationVariable
public Expression getIdentificationVariable()
Returns theExpression
that represents the identification variable.- Returns:
- The expression that was parsed representing the identification variable
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getIdentifier
public java.lang.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
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getJoinAssociationPath
public Expression getJoinAssociationPath()
Returns theExpression
that represents the join association path expression.- Returns:
- The expression that was parsed representing the join association path expression
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getOnClause
public Expression getOnClause()
Returns theExpression
that represents the ON clause if present.- Returns:
- The expression that was parsed representing the identification variable
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getQueryBNF
public JPQLQueryBNF getQueryBNF()
Returns the BNF of thisExpression
.- Returns:
- The
JPQLQueryBNF
, which represents the grammar of thisExpression
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hasAs
public boolean hasAs()
Determines whether the identifier AS was parsed.- Returns:
true
if the identifier AS was parsed;false
otherwise
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hasFetch
public boolean hasFetch()
Determines whether the identifier FETCH was parsed.- Returns:
true
if the identifier FETCH was parsed;false
otherwise
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hasIdentificationVariable
public boolean hasIdentificationVariable()
Determines whether the identification variable was parsed.- Returns:
true
if the identification variable was parsed;false
otherwise
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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
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hasOnClause
public boolean hasOnClause()
Determines whether the ON clause was parsed.- Returns:
true
if the ON clause was parsed;false
otherwise
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hasSpaceAfterAs
public boolean hasSpaceAfterAs()
Determines whether a whitespace was parsed after AS.- Returns:
true
if there was a whitespace after AS;false
otherwise
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hasSpaceAfterIdentificationVariable
public boolean hasSpaceAfterIdentificationVariable()
Determines whether a whitespace was parsed before ON.- Returns:
true
if there was a whitespace before ON;false
otherwise
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hasSpaceAfterJoin
public boolean hasSpaceAfterJoin()
Determines whether a whitespace was parsed after JOIN.- Returns:
true
if there was a whitespace after JOIN;false
otherwise
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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
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isLeftJoin
public boolean isLeftJoin()
Determines whether thisJoin
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 thisJoin
expression is aExpression.LEFT_JOIN
,Expression.LEFT_JOIN_FETCH
,Expression.LEFT_OUTER_JOIN
,Expression.LEFT_OUTER_JOIN_FETCH
;false
otherwise
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