java.lang.Object
- org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
- - org.eclipse.persistence.jpa.jpql.parser.WhenClause

All Implemented Interfaces:

Expression
```
public final class WhenClause
extends AbstractExpression
```
A WHEN predicate is used to calculate a condition and when it's true, its THEN will be executed.
BNF: when_clause ::= WHEN conditional_expression THEN scalar_expression
or
BNF: simple_when_clause ::= WHEN scalar_expression THEN scalar_expression

Since:

2.3

Version:

2.5

Author:

Pascal Filion

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

WhenClause(AbstractExpression parent)
Creates a new WhenClause.

Method Summary

All Methods Instance Methods Concrete Methods
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`.
`CollectionExpression`	`buildWhenCollectionExpression()`	Creates a new `CollectionExpression` that will wrap the single `WHEN` expression.
`JPQLQueryBNF`	`findQueryBNF(Expression expression)`	Retrieves the `JPQLQueryBNF` that represents the fragment of this `Expression` that was used when parsing the given `Expression`.
`String`	`getActualThenIdentifier()`	Returns the actual THEN found in the string representation of the JPQL query, which has the actual case that was used.
`String`	`getActualWhenIdentifier()`	Returns the actual WHEN found in the string representation of the JPQL query, which has the actual case that was used.
`JPQLQueryBNF`	`getQueryBNF()`	Returns the BNF of this `Expression`.
`AbstractExpression`	`getThenExpression()`	Returns the `Expression` representing the expression following the identifier THEN.
`AbstractExpression`	`getWhenExpression()`	Returns the `Expression` representing the conditional predicate of the clause.
`boolean`	`hasSpaceAfterThen()`	Determines whether a whitespace was parsed after THEN.
`boolean`	`hasSpaceAfterWhen()`	Determines whether a whitespace was parsed after WHEN.
`boolean`	`hasSpaceAfterWhenExpression()`	Determines whether a whitespace was parsed after the conditional expression.
`boolean`	`hasThen()`	Determines whether the identifier THEN was part of the query.
`boolean`	`hasThenExpression()`	Determines whether the THEN expression of the query was parsed.
`boolean`	`hasWhenExpression()`	Determines whether the conditional expression of the query was parsed.

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

- Constructor Detail
  - WhenClause
```
public WhenClause(AbstractExpression parent)
```
    Creates a new WhenClause.
    
    Parameters:
    
    parent - The parent of this expression
- 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.
  - buildWhenCollectionExpression
```
public CollectionExpression buildWhenCollectionExpression()
```
    Creates a new CollectionExpression that will wrap the single WHEN expression.
    
    Returns:
    
    The single WHEN expression represented by a temporary collection
  - 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
  - getActualThenIdentifier
```
public String getActualThenIdentifier()
```
    Returns the actual THEN found in the string representation of the JPQL query, which has the actual case that was used.
    
    Returns:
    
    The THEN identifier that was actually parsed, or an empty string if it was not parsed
  - getActualWhenIdentifier
```
public String getActualWhenIdentifier()
```
    Returns the actual WHEN found in the string representation of the JPQL query, which has the actual case that was used.
    
    Returns:
    
    The WHEN identifier that was actually parsed
  - getQueryBNF
```
public JPQLQueryBNF getQueryBNF()
```
    Returns the BNF of this Expression.
    
    Returns:
    
    The JPQLQueryBNF, which represents the grammar of this Expression
  - getThenExpression
```
public AbstractExpression getThenExpression()
```
    Returns the Expression representing the expression following the identifier THEN.
    
    Returns:
    
    The expression representing the expression executed if the predicate is true
  - getWhenExpression
```
public AbstractExpression getWhenExpression()
```
    Returns the Expression representing the conditional predicate of the clause.
    
    Returns:
    
    The expression following the WHEN identifier
  - hasSpaceAfterThen
```
public boolean hasSpaceAfterThen()
```
    Determines whether a whitespace was parsed after THEN.
    
    Returns:
    
    true if there was a whitespace after THEN; false otherwise
  - hasSpaceAfterWhen
```
public boolean hasSpaceAfterWhen()
```
    Determines whether a whitespace was parsed after WHEN.
    
    Returns:
    
    true if there was a whitespace after WHEN; false otherwise
  - hasSpaceAfterWhenExpression
```
public boolean hasSpaceAfterWhenExpression()
```
    Determines whether a whitespace was parsed after the conditional expression.
    
    Returns:
    
    true if there was a whitespace after the conditional expression; false otherwise
  - hasThen
```
public boolean hasThen()
```
    Determines whether the identifier THEN was part of the query.
    
    Returns:
    
    true if the identifier THEN was parsed; false otherwise
  - hasThenExpression
```
public boolean hasThenExpression()
```
    Determines whether the THEN expression of the query was parsed.
    
    Returns:
    
    true the THEN expression was parsed; false if nothing was parsed
  - hasWhenExpression
```
public boolean hasWhenExpression()
```
    Determines whether the conditional expression of the query was parsed.
    
    Returns:
    
    true the conditional expression was parsed; false if nothing was parsed

Class WhenClause

Field Summary

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

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

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Constructor Detail

WhenClause

Method Detail

accept

acceptChildren

buildWhenCollectionExpression

findQueryBNF

getActualThenIdentifier

getActualWhenIdentifier

getQueryBNF

getThenExpression

getWhenExpression

hasSpaceAfterThen

hasSpaceAfterWhen

hasSpaceAfterWhenExpression

hasThen

hasThenExpression

hasWhenExpression