org.eclipse.persistence.jpa.jpql.parser

Class AbstractFromClause

java.lang.Object

org.eclipse.persistence.jpa.jpql.parser.AbstractExpression

org.eclipse.persistence.jpa.jpql.parser.AbstractFromClause

All Implemented Interfaces:

Expression

Direct Known Subclasses:

FromClause, SimpleFromClause

public abstract class AbstractFromClause
extends AbstractExpression

The FROM clause of a query defines the domain of the query by declaring identification variables. An identification variable is an identifier declared in the FROM clause of a query. The domain of the query may be constrained by path expressions. Identification variables designate instances of a particular entity abstract schema type. The FROM clause can contain multiple identification variable declarations separated by a comma (,).

Since:

2.3

Version:

2.4.2

Author:

Pascal Filion

See Also:

FromClause, SimpleFromClause

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, ASC, AVG, BETWEEN, BIT_LENGTH, BOTH, CASE, CAST, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, COLUMN, CONCAT, 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, 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, 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_FIRST, NULLS_LAST, OBJECT, OF, ON, OPERATOR, OR, ORDER_BY, OUTER, PLUS, POSITION, POSITIONAL_PARAMETER, QUOTE, REGEXP, SELECT, SET, SIZE, SOME, SQL, SQRT, SUBSTRING, SUM, TABLE, THEN, TRAILING, TREAT, TRIM, TRUE, TYPE, UNION, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE

Method Summary

Modifier and Type	Method and Description
void	acceptChildren(ExpressionVisitor visitor) Visits the children of this Expression.
CollectionExpression	buildCollectionExpression() Creates a new CollectionExpression that will wrap the single declaration.
abstract java.lang.String	declarationBNF() Returns the BNF of the declaration part of this clause.
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	getActualIdentifier() Returns the actual FROM identifier found in the string representation of the JPQL query, which has the actual case that was used.
Expression	getDeclaration() Returns the Expression that represents the declaration of this clause.
boolean	hasDeclaration() Determines whether the declaration of this clause was parsed.
boolean	hasSpaceAfterFrom() Determines whether a whitespace was parsed after the FROM identifier.

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

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

accept, getQueryBNF

Method Detail

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.

buildCollectionExpression

public final CollectionExpression buildCollectionExpression()

Creates a new CollectionExpression that will wrap the single declaration.

Returns:

The single declaration represented by a temporary collection

declarationBNF

public abstract java.lang.String declarationBNF()

Returns the BNF of the declaration part of this clause.

Returns:

The BNF of the declaration part of this clause

findQueryBNF

public final 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

getActualIdentifier

public final java.lang.String getActualIdentifier()

Returns the actual FROM identifier found in the string representation of the JPQL query, which has the actual case that was used.

Returns:

The FROM identifier that was actually parsed

getDeclaration

public final Expression getDeclaration()

Returns the Expression that represents the declaration of this clause.

Returns:

The expression that was parsed representing the declaration

hasDeclaration

public final boolean hasDeclaration()

Determines whether the declaration of this clause was parsed.

Returns:

true if the declaration of this clause was parsed; false if it was not parsed

hasSpaceAfterFrom

public final boolean hasSpaceAfterFrom()

Determines whether a whitespace was parsed after the FROM identifier.

Returns:

true if a whitespace was parsed after the FROM identifier; false otherwise