org.eclipse.persistence.jpa.jpql.parser
Class ComparisonExpression

java.lang.Object
  org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
      org.eclipse.persistence.jpa.jpql.parser.CompoundExpression
          org.eclipse.persistence.jpa.jpql.parser.ComparisonExpression

All Implemented Interfaces:

Expression

public final class ComparisonExpression
extends CompoundExpression

Only the values of like types are permitted to be compared. A type is like another type if they correspond to the same Java language type, or if one is a primitive Java language type and the other is the wrapped Java class type equivalent (e.g., int and Integer are like types in this sense).

There is one exception to this rule: it is valid to compare numeric values for which the rules of numeric promotion apply. Conditional expressions attempting to compare non-like type values are disallowed except for this numeric case.

Note that the arithmetic operators and comparison operators are permitted to be applied to state-fields and input parameters of the wrapped Java class equivalents to the primitive numeric Java types. Two entities of the same abstract schema type are equal if and only if they have the same primary key value. Only equality/inequality comparisons over enumeration constants are required to be supported.

JPA 1.0 - BNF:

comparison_expression ::= string_expression comparison_operator {string_expression | all_or_any_expression} |
                          boolean_expression {=|<>} {boolean_expression | all_or_any_expression} |
                          enum_expression {=|<>} {enum_expression | all_or_any_expression} |
                          datetime_expression comparison_operator {datetime_expression | all_or_any_expression} |
                          entity_expression {=|<>} {entity_expression | all_or_any_expression} |
                          arithmetic_expression comparison_operator {arithmetic_expression | all_or_any_expression}

JPA 2.0 - BNF:

comparison_expression ::= string_expression comparison_operator {string_expression | all_or_any_expression} |
                          boolean_expression {=|<>} {boolean_expression | all_or_any_expression} |
                          enum_expression {=|<>} {enum_expression | all_or_any_expression} |
                          datetime_expression comparison_operator {datetime_expression | all_or_any_expression} |
                          entity_expression {=|<>} {entity_expression | all_or_any_expression} |
                          arithmetic_expression comparison_operator {arithmetic_expression | all_or_any_expression} |
                          entity_type_expression {=|<>} entity_type_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

ComparisonExpression(AbstractExpression parent, java.lang.String identifier)
Creates a new ComparisonExpression.

Method Summary

void	accept(ExpressionVisitor visitor) Visits this Expression by the given visitor.
java.lang.String	getComparisonOperator() Returns the comparison operator, which is either '=', '>', '>=', '<', '<=' or '<>'.
java.lang.String	getLeftExpressionQueryBNFId() Returns the unique identifier of the JPQLQueryBNF for the left expression.
JPQLQueryBNF	getQueryBNF() Returns the BNF of this Expression.
java.lang.String	getRightExpressionQueryBNFId() Returns the unique identifier of the JPQLQueryBNF for the right expression.
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 java.lang.String	parseIdentifier(WordParser wordParser) Parses the identifier of this expression.

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

acceptChildren, addChildrenTo, addOrderedChildrenTo, findQueryBNF, getActualIdentifier, getIdentifier, getLeftExpression, getRightExpression, hasLeftExpression, hasRightExpression, hasSpaceAfterIdentifier, parse, setLeftExpression, setRightExpression, 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

ComparisonExpression

public ComparisonExpression(AbstractExpression parent,
                            java.lang.String identifier)

Creates a new ComparisonExpression.

Parameters:

parent - The parent of this expression

identifier - The comparator identifier

Method Detail

accept

public void accept(ExpressionVisitor visitor)

Visits this Expression by the given visitor.

Parameters:

visitor - The ExpressionVisitor to visit this object

getComparisonOperator

public java.lang.String getComparisonOperator()

Returns the comparison operator, which is either '=', '>', '>=', '<', '<=' or '<>'.

Returns:

The operator comparing the two expressions

getLeftExpressionQueryBNFId

public java.lang.String getLeftExpressionQueryBNFId()

Returns the unique identifier of the JPQLQueryBNF for the left expression.

Specified by:

getLeftExpressionQueryBNFId in class CompoundExpression

Returns:

The ID of the BNF used when parsing the expression before the identifier

getQueryBNF

public JPQLQueryBNF getQueryBNF()

Returns the BNF of this Expression.

Returns:

The JPQLQueryBNF, which represents the grammar of this Expression

getRightExpressionQueryBNFId

public java.lang.String getRightExpressionQueryBNFId()

Returns the unique identifier of the JPQLQueryBNF for the right expression.

Specified by:

getRightExpressionQueryBNFId in class CompoundExpression

Returns:

The ID of the BNF used when parsing the expression after the identifier

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

parseIdentifier

protected java.lang.String parseIdentifier(WordParser wordParser)

Parses the identifier of this expression.

Specified by:

parseIdentifier in class CompoundExpression

Returns:

The identifier for this expression