Oracle Fusion Middleware Java API Reference for Oracle TopLink
11g Release 1 (11.1.1)

E28847-01


org.eclipse.persistence.jpa.internal.jpql.parser
Class WhenClause

java.lang.Object
  extended by org.eclipse.persistence.jpa.internal.jpql.parser.StringExpression
      extended by org.eclipse.persistence.jpa.internal.jpql.parser.AbstractExpression
          extended by org.eclipse.persistence.jpa.internal.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:
2.3
Author:
Pascal Filion

Field Summary
private  boolean hasSpaceAfterThen
          Determines whether a whitespace was parsed after the identifier THEN.
private  boolean hasSpaceAfterWhen
          Determines whether a whitespace was parsed after the identifier WHEN.
private  boolean hasSpaceAfterWhenExpression
          Determines whether a whitespace was parsed after the conditional expression.
private  boolean hasThen
          Determines whether the identifier THEN was parsed.
private  AbstractExpression thenExpression
          The Expression representing the expression following the identifier THEN.
private  AbstractExpression whenExpression
          The Expression representing the conditional predicate of the clause.
 
Fields inherited from class org.eclipse.persistence.jpa.internal.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.internal.jpql.parser.Expression
ABS, ALL, AND, ANY, AS, ASC, AVG, BETWEEN, BIT_LENGTH, BOTH, CASE, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, CONCAT, COUNT, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, DELETE, DELETE_FROM, DESC, DIFFERENT, DISTINCT, DIVISION, ELSE, EMPTY, END, ENTRY, EQUAL, ESCAPE, EXISTS, FALSE, FETCH, FROM, FUNC, GREATER_THAN, GREATER_THAN_OR_EQUAL, GROUP_BY, HAVING, IN, INDEX, INNER, INNER_JOIN, INNER_JOIN_FETCH, 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_EXISTS, NOT_IN, NOT_LIKE, NOT_MEMBER, NOT_MEMBER_OF, NULL, NULLIF, OBJECT, OF, OR, ORDER_BY, OUTER, PLUS, POSITION, POSITIONAL_PARAMETER, QUOTE, SELECT, SET, SIZE, SOME, SQRT, SUBSTRING, SUM, THEN, TRAILING, TREAT, TRIM, TRUE, TYPE, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE
 
Constructor Summary
WhenClause(AbstractExpression parent)
          Creates a new WhenClause.
 
Method Summary
 void accept(ExpressionVisitor visitor)
          Visits this Expression by the given visitor.
 void acceptChildren(ExpressionVisitor visitor)
          Visits the children of this Expression.
(package private)  void addChildrenTo(java.util.Collection<Expression> children)
          Adds the children of this Expression to the given collection.
(package private)  void addOrderedChildrenTo(java.util.List<StringExpression> children)
          Adds the StringExpressions representing this Expression.
 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.
(package private)  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.
(package private)  void parse(WordParser wordParser, boolean tolerant)
          Parses the query by starting at the current position, which is part of the given WordParser.
(package private)  void toParsedText(java.lang.StringBuilder writer, boolean includeVirtual)
          Generates a string representation of this Expression.
 
Methods inherited from class org.eclipse.persistence.jpa.internal.jpql.parser.AbstractExpression
buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, children, expressionFactory, expressionFactoryForIdentifier, findQueryBNF, getChildren, getJPAVersion, getParent, getRoot, getText, handleAggregate, identifierRole, identifiers, identifiers, identifierVersion, isAncestor, isIdentifier, isNull, isTolerant, isUnknown, isVirtual, orderedChildren, parse, parseSingleExpression, populatePosition, queryBNF, readdLeadingSpaces, 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
 

Field Detail

hasSpaceAfterThen

private boolean hasSpaceAfterThen
Determines whether a whitespace was parsed after the identifier THEN.

hasSpaceAfterWhen

private boolean hasSpaceAfterWhen
Determines whether a whitespace was parsed after the identifier WHEN.

hasSpaceAfterWhenExpression

private boolean hasSpaceAfterWhenExpression
Determines whether a whitespace was parsed after the conditional expression.

hasThen

private boolean hasThen
Determines whether the identifier THEN was parsed.

thenExpression

private AbstractExpression thenExpression
The Expression representing the expression following the identifier THEN.

whenExpression

private AbstractExpression whenExpression
The Expression representing the conditional predicate of the clause.
Constructor Detail

WhenClause

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 visitor 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() or Expression.getChildren() is called.

This does not traverse the Expression sub-hierarchy, use an subclass of AbstractTraverseChildrenVisitor in order to traverse the entire sub-hierarchy.

Parameters:
visitor - The visitor to visit the children of this object.

addChildrenTo

void addChildrenTo(java.util.Collection<Expression> children)
Adds the children of this Expression to the given collection.
Overrides:
addChildrenTo in class AbstractExpression
Parameters:
children - The collection used to store the children

addOrderedChildrenTo

void addOrderedChildrenTo(java.util.List<StringExpression> children)
Adds the StringExpressions representing this Expression.
Overrides:
addOrderedChildrenTo in class AbstractExpression
Parameters:
children - The list used to store the string representation of this Expression

getQueryBNF

public JPQLQueryBNF getQueryBNF()
Returns the BNF of this Expression.
Specified by:
getQueryBNF in class AbstractExpression
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

isParsingComplete

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

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

void toParsedText(java.lang.StringBuilder writer,
                  boolean includeVirtual)
Generates a string representation of this Expression.
Specified by:
toParsedText in class AbstractExpression
Parameters:
writer - The buffer used to append this Expression's string representation
includeVirtual - Determines whether to include any characters that are considered virtual, i.e. that was parsed when the query is incomplete and is needed for functionality like content assist

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