org.eclipse.persistence.jpa.jpql.parser

Class WhenClause

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

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 and Description
WhenClause(AbstractExpression parent) Creates a new WhenClause.

Method Summary

Modifier and Type	Method and 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.
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.
java.lang.String	getActualThenIdentifier() Returns the actual THEN found in the string representation of the JPQL query, which has the actual case that was used.
java.lang.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.
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

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.

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

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 java.lang.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 java.lang.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

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