Mod operator

data-prepper-expression/src/main/antlr/DataPrepperExpression.g4

@@ -29,7 +29,7 @@ arithmeticExpression
     ;
 
 multiplicativeExpression
-    : multiplicativeExpression (MULTIPLY | DIVIDE) arithmeticTerm
+    : multiplicativeExpression (MULTIPLY | DIVIDE | MOD) arithmeticTerm
     | arithmeticTerm
     ;
 
@@ -334,6 +334,7 @@ ZERO : '0';
 PLUS: '+';
 MULTIPLY: '*';
 DOT : '.';
+MOD: '%';
 EXPONENTLETTER
     : 'E'
     | 'e'

data-prepper-expression/src/main/java/org/opensearch/dataprepper/expression/ArithmeticBinaryOperator.java

@@ -49,12 +49,20 @@ public Number evaluate(final Object ... args) {
         final Class<?> leftValueClass = leftValue.getClass();
         final Class<?> rightValueClass = rightValue.getClass();
         if (!operandsToOperationMap.containsKey(leftValueClass)) {
-            throw new IllegalArgumentException(displayName + " requires left operand to be either Float or Integer.");
+            if (symbol == DataPrepperExpressionParser.MOD) {
+                throw new IllegalArgumentException(displayName + " requires left operand to be an Integer.");
+            } else {
+                throw new IllegalArgumentException(displayName + " requires left operand to be either Float or Integer.");
+            }
         }
         Map<Class<? extends Number>, BiFunction<Object, Object, Number>> rightOperandToOperation =
                 operandsToOperationMap.get(leftValueClass);
         if (!rightOperandToOperation.containsKey(rightValueClass)) {
-            throw new IllegalArgumentException(displayName + " requires right operand to be either Float or Integer.");
+            if (symbol == DataPrepperExpressionParser.MOD) {
+                throw new IllegalArgumentException(displayName + " requires right operand to be an Integer.");
+            } else {
+                throw new IllegalArgumentException(displayName + " requires right operand to be either Float or Integer.");
+            }
         }
         final BiFunction<Object, Object, Number> operation = rightOperandToOperation.get(rightValueClass);
         return operation.apply(leftValue, rightValue);

data-prepper-expression/src/main/java/org/opensearch/dataprepper/expression/OperatorConfiguration.java

@@ -417,7 +417,7 @@ public ArithmeticBinaryOperator divideOperator() {
                 operandsToOperationMap = new HashMap<>();
         final Map<Class<? extends Number>, BiFunction<Object, Object, Number>> intOperations =
                 Map.of(
-                        Integer.class, (lhs, rhs) -> ((double)(int)lhs) /((double)(int)rhs),
+                        Integer.class, (lhs, rhs) -> ((double)(int)lhs) / ((double)(int)rhs),
                         Float.class, (lhs, rhs) -> (float)(int)lhs / (Float) rhs,
                         Long.class, (lhs, rhs) -> (double)(int)lhs / (Long) rhs,
                         Double.class, (lhs, rhs) -> (double)(int)lhs / (Double) rhs
@@ -451,4 +451,18 @@ public ArithmeticBinaryOperator divideOperator() {
 
         return new ArithmeticBinaryOperator(DataPrepperExpressionParser.DIVIDE, operandsToOperationMap);
     }
+
+    @Bean
+    public ArithmeticBinaryOperator modOperator() {
+        final Map<Class<? extends Number>, Map<Class<? extends Number>, BiFunction<Object, Object, Number>>>
+                operandsToOperationMap = new HashMap<>();
+        final Map<Class<? extends Number>, BiFunction<Object, Object, Number>> intOperations =
+                Map.of(
+                        Integer.class, (lhs, rhs) -> ((int)lhs) % ((int)rhs)
+                );
+
+        operandsToOperationMap.put(Integer.class, intOperations);
+
+        return new ArithmeticBinaryOperator(DataPrepperExpressionParser.MOD, operandsToOperationMap);
+    }
 }

data-prepper-expression/src/test/java/org/opensearch/dataprepper/expression/ArithmeticBinaryOperatorTest.java

@@ -37,6 +37,10 @@ private Operator createDivideOperatorUnderTest() {
         return new OperatorConfiguration().divideOperator();
     }
 
+    private Operator createModOperatorUnderTest() {
+        return new OperatorConfiguration().modOperator();
+    }
+
     @Mock
     private ParserRuleContext ctx;
 
@@ -48,6 +52,8 @@ void testGetNumberOfOperands() {
         assertThat(objectUnderTest.getNumberOfOperands(ctx), is(2));
         objectUnderTest = createDivideOperatorUnderTest();
         assertThat(objectUnderTest.getNumberOfOperands(ctx), is(2));
+        objectUnderTest = createModOperatorUnderTest();
+        assertThat(objectUnderTest.getNumberOfOperands(ctx), is(2));
 
         when(ctx.getRuleIndex()).thenReturn(DataPrepperExpressionParser.RULE_arithmeticExpression);
         objectUnderTest = createSubtractOperatorUnderTest();
@@ -82,6 +88,12 @@ void testShouldEvaluate() {
         assertThat(objectUnderTest.shouldEvaluate(ctx), is(true));
         when(ctx.getRuleIndex()).thenReturn(-1);
         assertThat(objectUnderTest.shouldEvaluate(ctx), is(false));
+
+        objectUnderTest = createModOperatorUnderTest();
+        when(ctx.getRuleIndex()).thenReturn(DataPrepperExpressionParser.RULE_multiplicativeExpression);
+        assertThat(objectUnderTest.shouldEvaluate(ctx), is(true));
+        when(ctx.getRuleIndex()).thenReturn(-1);
+        assertThat(objectUnderTest.shouldEvaluate(ctx), is(false));
     }
 
     @Test
@@ -94,6 +106,8 @@ void testGetSymbol() {
         assertThat(objectUnderTest.getSymbol(), is(DataPrepperExpressionParser.MULTIPLY));
         objectUnderTest = createDivideOperatorUnderTest();
         assertThat(objectUnderTest.getSymbol(), is(DataPrepperExpressionParser.DIVIDE));
+        objectUnderTest = createModOperatorUnderTest();
+        assertThat(objectUnderTest.getSymbol(), is(DataPrepperExpressionParser.MOD));
     }
 
     @Test
@@ -106,6 +120,10 @@ void testInvalid() {
         assertThrows(RuntimeException.class, () -> objectUnderTest.evaluate(2, 1, 2));
         objectUnderTest = createDivideOperatorUnderTest();
         assertThrows(RuntimeException.class, () -> objectUnderTest.evaluate(2, 1, 2));
+        objectUnderTest = createModOperatorUnderTest();
+        assertThrows(RuntimeException.class, () -> objectUnderTest.evaluate(2, 1, 2));
+        assertThrows(RuntimeException.class, () -> objectUnderTest.evaluate(2.0, 1));
+        assertThrows(RuntimeException.class, () -> objectUnderTest.evaluate(2, 1.0));
     }
 
     @Test
@@ -204,4 +222,11 @@ void testEvalValidArgsForDivide() {
         assertThat(objectUnderTest.evaluate(5.0, 2.0), is(2.5));
     }
 
+    @Test
+    void testEvalValidArgsForMod() {
+        objectUnderTest = createModOperatorUnderTest();
+        assertThat(objectUnderTest.evaluate(5, 5), is(0));
+        assertThat(objectUnderTest.evaluate(5, 2), is(1));
+        assertThat(objectUnderTest.evaluate(6, 3), is(0));
+    }
 }

data-prepper-expression/src/test/java/org/opensearch/dataprepper/expression/ParseTreeEvaluatorListenerTest.java

@@ -56,6 +56,7 @@ class ParseTreeEvaluatorListenerTest {
             operatorConfiguration.subtractOperator(),
             operatorConfiguration.multiplyOperator(),
             operatorConfiguration.divideOperator(),
+            operatorConfiguration.modOperator(),
             new NotOperator()
     );
     private final OperatorProvider operatorProvider = new OperatorProvider(operators);