org.apache.activemq.artemis.selector.filter

## Class ComparisonExpression

- java.lang.Object
- - org.apache.activemq.artemis.selector.filter.BinaryExpression
  - - org.apache.activemq.artemis.selector.filter.ComparisonExpression

- All Implemented Interfaces:
    BooleanExpression, Expression

      public abstract class ComparisonExpression
      extends BinaryExpression
      implements BooleanExpression

  A filter performing a comparison of two objects
  Version:
    $Revision: 1.2 $

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static ThreadLocal<Boolean>` | `CONVERT_STRING_EXPRESSIONS`

    - ### Fields inherited from class org.apache.activemq.artemis.selector.filter.BinaryExpression

      `left, right`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ComparisonExpression(Expression left, Expression right)`

  - ### Method Summary

    All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected abstract boolean` | `asBoolean(int answer)`
    `static void` | `checkEqualOperand(Expression expr)` Validates that the expression can be used in `==` or `<>` expression.
    `static void` | `checkLessThanOperand(Expression expr)` Only Numeric expressions can be used in `>`, `>=`, `<` or `<=` expressions.
    `protected Boolean` | `compare(Comparable lv, Comparable rv)`
    `static BooleanExpression` | `createBetween(Expression value, Expression left, Expression right)`
    `static BooleanExpression` | `createEqual(Expression left, Expression right)`
    `static BooleanExpression` | `createGreaterThan(Expression left, Expression right)`
    `static BooleanExpression` | `createGreaterThanEqual(Expression left, Expression right)`
    `static BooleanExpression` | `createInFilter(Expression left, List elements)`
    `static BooleanExpression` | `createIsNotNull(Expression left)`
    `static BooleanExpression` | `createIsNull(Expression left)`
    `static BooleanExpression` | `createLessThan(Expression left, Expression right)`
    `static BooleanExpression` | `createLessThanEqual(Expression left, Expression right)`
    `static BooleanExpression` | `createLike(Expression left, String right, String escape)`
    `static BooleanExpression` | `createNotBetween(Expression value, Expression left, Expression right)`
    `static BooleanExpression` | `createNotEqual(Expression left, Expression right)`
    `static BooleanExpression` | `createNotInFilter(Expression left, List elements)`
    `static BooleanExpression` | `createNotLike(Expression left, String right, String escape)`
    `Object` | `evaluate(Filterable message)`
    `boolean` | `matches(Filterable message)`

    - ### Methods inherited from class org.apache.activemq.artemis.selector.filter.BinaryExpression

      `equals, getExpressionSymbol, getLeft, getRight, hashCode, setLeft, setRight, toString`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Field Detail

    - #### CONVERT_STRING_EXPRESSIONS

          public static final ThreadLocal<Boolean> CONVERT_STRING_EXPRESSIONS

  - ### Constructor Detail

    - #### ComparisonExpression

          public ComparisonExpression(Expression left,
                                      Expression right)

      Parameters:
        `left` -
        `right` -

  - ### Method Detail

    - #### createBetween

          public static BooleanExpression createBetween(Expression value,
                                                        Expression left,
                                                        Expression right)

    - #### createNotBetween

          public static BooleanExpression createNotBetween(Expression value,
                                                           Expression left,
                                                           Expression right)

    - #### createLike

          public static BooleanExpression createLike(Expression left,
                                                     String right,
                                                     String escape)

    - #### createNotLike

          public static BooleanExpression createNotLike(Expression left,
                                                        String right,
                                                        String escape)

    - #### createInFilter

          public static BooleanExpression createInFilter(Expression left,
                                                         List elements)

    - #### createNotInFilter

          public static BooleanExpression createNotInFilter(Expression left,
                                                            List elements)

    - #### createIsNull

          public static BooleanExpression createIsNull(Expression left)

    - #### createIsNotNull

          public static BooleanExpression createIsNotNull(Expression left)

    - #### createNotEqual

          public static BooleanExpression createNotEqual(Expression left,
                                                         Expression right)

    - #### createEqual

          public static BooleanExpression createEqual(Expression left,
                                                      Expression right)

    - #### createGreaterThan

          public static BooleanExpression createGreaterThan(Expression left,
                                                            Expression right)

    - #### createGreaterThanEqual

          public static BooleanExpression createGreaterThanEqual(Expression left,
                                                                 Expression right)

    - #### createLessThan

          public static BooleanExpression createLessThan(Expression left,
                                                         Expression right)

    - #### createLessThanEqual

          public static BooleanExpression createLessThanEqual(Expression left,
                                                              Expression right)

    - #### checkLessThanOperand

          public static void checkLessThanOperand(Expression expr)

      Only Numeric expressions can be used in `>`, `>=`, `<` or `<=` expressions.
      Parameters:
        `expr` -

    - #### checkEqualOperand

          public static void checkEqualOperand(Expression expr)

      Validates that the expression can be used in `==` or `<>` expression. Cannot not be NULL TRUE or FALSE litterals.
      Parameters:
        `expr` -

    - #### evaluate

          public Object evaluate(Filterable message)
                          throws FilterException

      Specified by:
        `evaluate` in interface `Expression`
      Returns:
        the value of this expression
      Throws:
        `FilterException`

    - #### compare

          protected Boolean compare(Comparable lv,
                                    Comparable rv)

    - #### asBoolean

          protected abstract boolean asBoolean(int answer)

    - #### matches

          public boolean matches(Filterable message)
                          throws FilterException

      Specified by:
        `matches` in interface `BooleanExpression`
      Returns:
        true if the expression evaluates to Boolean.TRUE.
      Throws:
        `FilterException`

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