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:

2.5

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, 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

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`acceptChildren(ExpressionVisitor visitor)`	Visits the children of this `Expression`.
`CollectionExpression`	`buildCollectionExpression()`	Creates a new `CollectionExpression` that will wrap the single declaration.
`JPQLQueryBNF`	`findQueryBNF(Expression expression)`	Retrieves the `JPQLQueryBNF` that represents the fragment of this `Expression` that was used when parsing the given `Expression`.
`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`	`getAsOfClause()`	Returns the `Expression` representing the AS OF clause.
`Expression`	`getDeclaration()`	Returns the `Expression` that represents the declaration of this clause.
`abstract String`	`getDeclarationQueryBNFId()`	Returns the BNF of the declaration part of this clause.
`Expression`	`getHierarchicalQueryClause()`	Returns the `Expression` representing the hierarchical query clause.
`boolean`	`hasAsOfClause()`	Determines whether the AS OF clause is defined.
`boolean`	`hasDeclaration()`	Determines whether the declaration of this clause was parsed.
`boolean`	`hasHierarchicalQueryClause()`	Determines whether the hierarchical query clause was parsed or not.
`boolean`	`hasSpaceAfterDeclaration()`	Determines whether a whitespace was found after the declaration query clause, which will be `true` if it's followed by either the hierarchical query clause or the `AS OF` clause.
`boolean`	`hasSpaceAfterFrom()`	Determines whether a whitespace was parsed after the FROM identifier.
`boolean`	`hasSpaceAfterHierarchicalQueryClause()`	Determines whether a whitespace was found after the hierarchical query clause.

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
  - 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 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
  - getAsOfClause
```
public final Expression getAsOfClause()
```
    Returns the Expression representing the AS OF clause.
    
    Returns:
    
    The expression representing the AS OF clause
  - getDeclaration
```
public final Expression getDeclaration()
```
    Returns the Expression that represents the declaration of this clause.
    
    Returns:
    
    The expression that was parsed representing the declaration
  - getDeclarationQueryBNFId
```
public abstract String getDeclarationQueryBNFId()
```
    Returns the BNF of the declaration part of this clause.
    
    Returns:
    
    The BNF of the declaration part of this clause
  - getHierarchicalQueryClause
```
public final Expression getHierarchicalQueryClause()
```
    Returns the Expression representing the hierarchical query clause.
    
    Returns:
    
    The expression representing the hierarchical query clause
    
    Since:
    
    2.5
  - hasAsOfClause
```
public final boolean hasAsOfClause()
```
    Determines whether the AS OF clause is defined.
    
    Returns:
    
    true if the query that got parsed had the AS OF clause
  - 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
  - hasHierarchicalQueryClause
```
public final boolean hasHierarchicalQueryClause()
```
    Determines whether the hierarchical query clause was parsed or not.
    
    Returns:
    
    true if the query that got parsed had the hierarchical query clause
    
    Since:
    
    2.5
  - hasSpaceAfterDeclaration
```
public final boolean hasSpaceAfterDeclaration()
```
    Determines whether a whitespace was found after the declaration query clause, which will be true if it's followed by either the hierarchical query clause or the AS OF clause.
    
    Returns:
    
    true if there was a whitespace after the declaration; false otherwise
    
    Since:
    
    2.5
  - 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
  - hasSpaceAfterHierarchicalQueryClause
```
public final boolean hasSpaceAfterHierarchicalQueryClause()
```
    Determines whether a whitespace was found after the hierarchical query clause. In some cases, the space is owned by a child of the hierarchical query clause.
    
    Returns:
    
    true if there was a whitespace after the hierarchical query clause and owned by this expression; false otherwise
    
    Since:
    
    2.5

Class AbstractFromClause

Field Summary

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

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

Method Summary

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

Methods inherited from class java.lang.Object

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

Method Detail

acceptChildren

buildCollectionExpression

findQueryBNF

getActualIdentifier

getAsOfClause

getDeclaration

getDeclarationQueryBNFId

getHierarchicalQueryClause

hasAsOfClause

hasDeclaration

hasHierarchicalQueryClause

hasSpaceAfterDeclaration

hasSpaceAfterFrom

hasSpaceAfterHierarchicalQueryClause