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_variableA 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_expressionEclipseLink 2.4
BNF:join_spec { abstract_schema_name | join_association_path_expression } [AS] identification_variable [join_condition]- Version:
- 2.5
- Author:
- Pascal Filion
- Since:
- 2.3
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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 voidaccept(ExpressionVisitor visitor)Visits thisExpressionby the givenvisitor.voidacceptChildren(ExpressionVisitor visitor)Visits the children of thisExpression.protected voidaddChildrenTo(java.util.Collection<Expression> children)Adds the children of thisAbstractExpressionto the given collection.protected voidaddOrderedChildrenTo(java.util.List<Expression> children)Adds the children of thisAbstractExpressionto the given list.JPQLQueryBNFfindQueryBNF(Expression expression)Retrieves theJPQLQueryBNFthat represents the fragment of thisExpressionthat was used when parsing the givenExpression.java.lang.StringgetActualAsIdentifier()Returns the actual AS found in the string representation of the JPQL query, which has the actual case that was used.java.lang.StringgetActualIdentifier()Returns the actual identifier found in the string representation of the JPQL query, which has the actual case that was used.ExpressiongetIdentificationVariable()Returns theExpressionthat represents the identification variable.java.lang.StringgetIdentifier()Returns the identifier this expression represents.ExpressiongetJoinAssociationPath()Returns theExpressionthat represents the join association path expression.ExpressiongetOnClause()Returns theExpressionthat represents the ON clause if present.JPQLQueryBNFgetQueryBNF()Returns the BNF of thisExpression.booleanhasAs()Determines whether the identifier AS was parsed.booleanhasFetch()Determines whether the identifier FETCH was parsed.booleanhasIdentificationVariable()Determines whether the identification variable was parsed.booleanhasJoinAssociationPath()Determines whether the join association path expression was parsed.booleanhasOnClause()Determines whether the ON clause was parsed.booleanhasSpaceAfterAs()Determines whether a whitespace was parsed after AS.booleanhasSpaceAfterIdentificationVariable()Determines whether a whitespace was parsed before ON.booleanhasSpaceAfterJoin()Determines whether a whitespace was parsed after JOIN.booleanhasSpaceAfterJoinAssociation()Determines whether a whitespace was parsed after the join association path expression.booleanisLeftJoin()Determines whether thisJoinis a left join, i.e.protected booleanisParsingComplete(WordParser wordParser, java.lang.String word, Expression expression)Determines whether the parsing is complete based on what is left in the given text.protected voidparse(WordParser wordParser, boolean tolerant)Parses the query by starting at the current position, which is part of the givenWordParser.protected voidtoParsedText(java.lang.StringBuilder writer, boolean actual)Generates a string representation of thisExpression, including its children, if it has any.-
Methods inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
acceptUnknownVisitor, acceptUnknownVisitor, buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, calculatePosition, children, findFallBackExpressionFactory, getExpressionFactory, getExpressionRegistry, getGrammar, getIdentifierVersion, getJPAVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, getText, handleAggregate, handleCollection, isAncestor, isIdentifier, isNull, isTolerant, isUnknown, isVirtual, orderedChildren, parse, parseUsingExpressionFactory, populatePosition, rebuildActualText, rebuildParsedText, setParent, setText, shouldParseWithFactoryFirst, shouldSkipLiteral, 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 thisExpressionby the givenvisitor.- Parameters:
visitor- TheExpressionVisitorto 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
Expressionsub-hierarchy, use a subclass ofAbstractTraverseChildrenVisitorin order to traverse the entire sub-hierarchy.- Parameters:
visitor- Thevisitorto visit the children of this object.
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addChildrenTo
protected void addChildrenTo(java.util.Collection<Expression> children)
Adds the children of thisAbstractExpressionto the given collection.- Overrides:
addChildrenToin classAbstractExpression- Parameters:
children- The collection used to store the children
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addOrderedChildrenTo
protected void addOrderedChildrenTo(java.util.List<Expression> children)
Adds the children of thisAbstractExpressionto the given list.- Overrides:
addOrderedChildrenToin classAbstractExpression- Parameters:
children- The list used to store the string representation of thisAbstractExpression
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findQueryBNF
public JPQLQueryBNF findQueryBNF(Expression expression)
Retrieves theJPQLQueryBNFthat represents the fragment of thisExpressionthat was used when parsing the givenExpression.- Specified by:
findQueryBNFin interfaceExpression- Overrides:
findQueryBNFin classAbstractExpression- Parameters:
expression- TheExpressionthat is a descendant of this one- Returns:
- The
JPQLQueryBNFthat 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 theExpressionthat 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 theExpressionthat 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 theExpressionthat 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:
trueif the identifier AS was parsed;falseotherwise
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hasFetch
public boolean hasFetch()
Determines whether the identifier FETCH was parsed.- Returns:
trueif the identifier FETCH was parsed;falseotherwise
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hasIdentificationVariable
public boolean hasIdentificationVariable()
Determines whether the identification variable was parsed.- Returns:
trueif the identification variable was parsed;falseotherwise
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hasJoinAssociationPath
public boolean hasJoinAssociationPath()
Determines whether the join association path expression was parsed.- Returns:
trueif the join association path expression was parsed;falseotherwise
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hasOnClause
public boolean hasOnClause()
Determines whether the ON clause was parsed.- Returns:
trueif the ON clause was parsed;falseotherwise
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hasSpaceAfterAs
public boolean hasSpaceAfterAs()
Determines whether a whitespace was parsed after AS.- Returns:
trueif there was a whitespace after AS;falseotherwise
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hasSpaceAfterIdentificationVariable
public boolean hasSpaceAfterIdentificationVariable()
Determines whether a whitespace was parsed before ON.- Returns:
trueif there was a whitespace before ON;falseotherwise
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hasSpaceAfterJoin
public boolean hasSpaceAfterJoin()
Determines whether a whitespace was parsed after JOIN.- Returns:
trueif there was a whitespace after JOIN;falseotherwise
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hasSpaceAfterJoinAssociation
public boolean hasSpaceAfterJoinAssociation()
Determines whether a whitespace was parsed after the join association path expression.- Returns:
trueif there was a whitespace after join association path expression;falseotherwise
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isLeftJoin
public boolean isLeftJoin()
Determines whether thisJoinis a left join, i.e.Expression.LEFT_JOIN,Expression.LEFT_JOIN_FETCH,Expression.LEFT_OUTER_JOIN,Expression.LEFT_OUTER_JOIN_FETCH.- Returns:
trueif thisJoinexpression is aExpression.LEFT_JOIN,Expression.LEFT_JOIN_FETCH,Expression.LEFT_OUTER_JOIN,Expression.LEFT_OUTER_JOIN_FETCH;falseotherwise
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isParsingComplete
protected boolean isParsingComplete(WordParser wordParser, java.lang.String word, Expression expression)
Determines whether the parsing is complete based on what is left in the given text. The text is never empty.- Overrides:
isParsingCompletein classAbstractExpression- Parameters:
wordParser- The text to parse based on the current position of the cursorword- The word that was retrieved from the given text, which is the first word in the textexpression- TheExpressionthat has already been parsed- Returns:
trueif the text no longer can't be parsed by the current expression;falseif more can be parsed
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parse
protected void parse(WordParser wordParser, boolean tolerant)
Parses the query by starting at the current position, which is part of the givenWordParser.- Specified by:
parsein classAbstractExpression- Parameters:
wordParser- The text to parse based on the current position of the cursortolerant- Determines whether the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries
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toParsedText
protected void toParsedText(java.lang.StringBuilder writer, boolean actual)Generates a string representation of thisExpression, including its children, if it has any.- Specified by:
toParsedTextin classAbstractExpression- Parameters:
writer- The buffer used to append thisExpression's string representationactual- Determines whether the string representation should represent what was parsed, i.e. include any "virtual" whitespace (such as ending whitespace) and the actual case of the JPQL identifiers
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