org.eclipse.persistence.jpa.jpql.parser

Class ExtractExpression

java.lang.Object

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

org.eclipse.persistence.jpa.jpql.parser.AbstractEncapsulatedExpression

org.eclipse.persistence.jpa.jpql.parser.AbstractSingleEncapsulatedExpression

org.eclipse.persistence.jpa.jpql.parser.ExtractExpression

All Implemented Interfaces:

Expression

public final class ExtractExpression
extends AbstractSingleEncapsulatedExpression

The EXTRACT function extracts a date part from a date/time value. The date part can be YEAR, MONTH, DAY, HOUR, MINUTE, SECOND. Some databases may support other parts.

BNF: extract_expression ::= EXTRACT(date_part_literal [FROM] scalar_expression)

date_part_literal ::= { MICROSECOND | SECOND | MINUTE | HOUR | DAY | WEEK | MONTH | QUARTER | YEAR | SECOND_MICROSECOND | MINUTE_MICROSECOND | MINUTE_SECOND | HOUR_MICROSECOND | HOUR_SECOND | HOUR_MINUTE | DAY_MICROSECOND | DAY_SECOND | DAY_MINUTE | DAY_HOUR | YEAR_MONTH, etc }

Version:

2.5

Author:

James Sutherland

Since:

2.4

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
ExtractExpression(AbstractExpression parent) Creates a new ExtractExpression.

Method Summary

Modifier and Type	Method and Description
void	accept(ExpressionVisitor visitor) Visits this Expression by the given visitor.
protected void	addOrderedEncapsulatedExpressionTo(java.util.List<Expression> children) Adds the Expressions representing the encapsulated Expression.
java.lang.String	getActualFromIdentifier() Returns the actual FROM identifier found in the string representation of the JPQL query, which has the actual case that was used.
java.lang.String	getDatePart() Returns the date part that was parsed, it is used to extract a single part of a date/time, such as year, month, day, your, etc.
java.lang.String	getEncapsulatedExpressionQueryBNFId() Returns the BNF used to parse the encapsulated expression.
JPQLQueryBNF	getQueryBNF() Returns the BNF of this Expression.
boolean	hasDatePart() Determines whether the date part literal was parsed or not.
boolean	hasEncapsulatedExpression() Determines whether something was parsed after the left parenthesis.
boolean	hasFrom() Determines whether the identifier FROM was part of the query.
boolean	hasSpaceAfterDatePart() Determines whether a whitespace was found after the date part literal.
boolean	hasSpaceAfterFrom() Determines whether a whitespace was found after FROM.
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	parseEncapsulatedExpression(WordParser wordParser, int whitespaceCount, boolean tolerant) Parses the encapsulated expression by starting at the current position, which is part of the given WordParser.
protected void	removeEncapsulatedExpression() Removes the encapsulated Expression that was parsed, it should not be part of this one.
protected void	toParsedTextEncapsulatedExpression(java.lang.StringBuilder writer, boolean actual) Generates a string representation of the encapsulated Expression.

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

acceptChildren, addChildrenTo, findQueryBNF, getExpression, hasExpression, setExpression

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

addOrderedChildrenTo, areLogicalIdentifiersSupported, getActualIdentifier, getIdentifier, hasLeftParenthesis, hasRightParenthesis, hasSpaceAfterIdentifier, parse, shouldParseRightParenthesis, toParsedText

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

ExtractExpression

public ExtractExpression(AbstractExpression parent)

Creates a new ExtractExpression.

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

addOrderedEncapsulatedExpressionTo

protected void addOrderedEncapsulatedExpressionTo(java.util.List<Expression> children)

Adds the Expressions representing the encapsulated Expression.

Overrides:

addOrderedEncapsulatedExpressionTo in class AbstractSingleEncapsulatedExpression

Parameters:

children - The list used to store the string representation of the encapsulated Expression

getEncapsulatedExpressionQueryBNFId

public java.lang.String getEncapsulatedExpressionQueryBNFId()

Returns the BNF used to parse the encapsulated expression.

Specified by:

getEncapsulatedExpressionQueryBNFId in class AbstractSingleEncapsulatedExpression

Returns:

The BNF used to parse the encapsulated expression

getActualFromIdentifier

public java.lang.String getActualFromIdentifier()

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, or an empty string if it was not parsed

getDatePart

public java.lang.String getDatePart()

Returns the date part that was parsed, it is used to extract a single part of a date/time, such as year, month, day, your, etc.

Returns:

The part of the date/time to retrieve

getQueryBNF

public JPQLQueryBNF getQueryBNF()

Returns the BNF of this Expression.

Returns:

The JPQLQueryBNF, which represents the grammar of this Expression

hasDatePart

public boolean hasDatePart()

Determines whether the date part literal was parsed or not.

Returns:

true if the date part literal was parsed; false otherwise

hasEncapsulatedExpression

public boolean hasEncapsulatedExpression()

Determines whether something was parsed after the left parenthesis.

Overrides:

hasEncapsulatedExpression in class AbstractSingleEncapsulatedExpression

Returns:

true if something was parsed; false otherwise

hasFrom

public boolean hasFrom()

Determines whether the identifier FROM was part of the query.

Returns:

true if the identifier FROM was parsed; false otherwise

hasSpaceAfterDatePart

public boolean hasSpaceAfterDatePart()

Determines whether a whitespace was found after the date part literal.

Returns:

true if there was a whitespace after the date part literal; false otherwise

hasSpaceAfterFrom

public boolean hasSpaceAfterFrom()

Determines whether a whitespace was found after FROM.

Returns:

true if there was a whitespace after FROM; false otherwise

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 AbstractEncapsulatedExpression

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

parseEncapsulatedExpression

protected void parseEncapsulatedExpression(WordParser wordParser,
                                           int whitespaceCount,
                                           boolean tolerant)

Parses the encapsulated expression by starting at the current position, which is part of the given WordParser.

Overrides:

parseEncapsulatedExpression in class AbstractSingleEncapsulatedExpression

Parameters:

wordParser - The text to parse based on the current position of the cursor

whitespaceCount - The number of whitespace characters that were parsed after '('

tolerant - Determines whether the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries

removeEncapsulatedExpression

protected void removeEncapsulatedExpression()

Removes the encapsulated Expression that was parsed, it should not be part of this one. This happens when the parsed information does not have both '(' and ')'.

Overrides:

removeEncapsulatedExpression in class AbstractSingleEncapsulatedExpression

toParsedTextEncapsulatedExpression

protected void toParsedTextEncapsulatedExpression(java.lang.StringBuilder writer,
                                                  boolean actual)

Generates a string representation of the encapsulated Expression.

Overrides:

toParsedTextEncapsulatedExpression in class AbstractSingleEncapsulatedExpression

Parameters:

writer - The buffer used to append the encapsulated Expression's string representation

actual - 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