Package org.eclipse.persistence.jpa.jpql.parser

Class 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

    • 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

      • 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

      • 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
        Parameters:
        wordParser - The WordParser containing the text to parse, which starts with the identifier
        Returns:
        The identifier for this expression