Package org.eclipse.persistence.jpa.jpql.parser

Class Join

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]

Version:

2.5

Author:

Pascal Filion

Since:

2.3

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, java.lang.String identifier)	Creates a new Join.

Method Summary

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.
protected void	addChildrenTo(java.util.Collection<Expression> children)	Adds the children of this AbstractExpression to the given collection.
protected void	addOrderedChildrenTo(java.util.List<Expression> children)	Adds the children of this AbstractExpression to the given list.
JPQLQueryBNF	findQueryBNF(Expression expression)	Retrieves the JPQLQueryBNF that represents the fragment of this Expression that was used when parsing the given Expression.
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 the Expression that represents the identification variable.
java.lang.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.
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.
protected void	parse(WordParser wordParser, boolean tolerant)	Parses the query by starting at the current position, which is part of the given WordParser.
protected void	toParsedText(java.lang.StringBuilder writer, boolean actual)	Generates a string representation of this Expression, 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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Join

public Join(AbstractExpression parent,
            java.lang.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.

addChildrenTo

protected void addChildrenTo(java.util.Collection<Expression> children)

Adds the children of this AbstractExpression to the given collection.

Overrides:

addChildrenTo in class AbstractExpression

Parameters:

children - The collection used to store the children

addOrderedChildrenTo

protected void addOrderedChildrenTo(java.util.List<Expression> children)

Adds the children of this AbstractExpression to the given list.

Overrides:

addOrderedChildrenTo in class AbstractExpression

Parameters:

children - The list used to store the string representation of this AbstractExpression

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 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

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

getIdentificationVariable

public Expression getIdentificationVariable()

Returns the Expression that represents the identification variable.

Returns:

The expression that was parsed representing the identification variable

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

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

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:

isParsingComplete in class AbstractExpression

Parameters:

wordParser - The text to parse based on the current position of the cursor

word - The word that was retrieved from the given text, which is the first word in the text

expression - The Expression that has already been parsed

Returns:

true if the text no longer can't be parsed by the current expression; false if more can be parsed

parse

protected void parse(WordParser wordParser,
                     boolean tolerant)

Parses the query by starting at the current position, which is part of the given WordParser.

Specified by:

parse in class AbstractExpression

Parameters:

wordParser - The text to parse based on the current position of the cursor

tolerant - Determines whether the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries

toParsedText

protected void toParsedText(java.lang.StringBuilder writer,
                            boolean actual)

Generates a string representation of this Expression, including its children, if it has any.

Specified by:

toParsedText in class AbstractExpression

Parameters:

writer - The buffer used to append this Expression's string representation

actual - 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