Changes to support $eq comparison operator. (#55)

src/main/java/io/stargate/sgv3/docsapi/StargateDocsV3Api.java

@@ -58,7 +58,7 @@
                       """
                       {
                         "findOne": {
-                            "filter": {"location": "London"}
+                            "filter": {"location": "London", "race.competitors" : {"$eq" : 100}}
                         }
                       }
                       """),
@@ -69,7 +69,7 @@
                       """
                       {
                         "find": {
-                             "filter": {"location": "London"},
+                             "filter": {"location": "London", "race.competitors" : {"$eq" : 100}},
                              "options": {"limit" : 1000, "pageSize": 25, "pagingState" : "Next paging state got from previous page call"}
                         }
                       }

src/main/java/io/stargate/sgv3/docsapi/api/model/command/clause/filter/ComparisonExpression.java

@@ -21,7 +21,7 @@ public record ComparisonExpression(
     @Valid @NotEmpty List<FilterOperation<?>> filterOperations) {
 
   /**
-   * Shortcut to create equals against a literal
+   * Shortcut to create equals against a literal, mare condition cannot be added using add().
    *
    * <p>e.g. {"username" : "aaron"}
    *
@@ -35,6 +35,19 @@ public static ComparisonExpression eq(String path, Object value) {
         List.of(new ValueComparisonOperation<>(ValueComparisonOperator.EQ, getLiteral(value))));
   }
 
+  /**
+   * Adds a comparison operation
+   *
+   * <p>e.g. {"username" : "aaron"}
+   *
+   * @param path Json node path
+   * @param value Value returned by the deserializer
+   * @return {@link ComparisonExpression} with equal operator
+   */
+  public void add(ValueComparisonOperator operator, Object value) {
+    filterOperations.add(new ValueComparisonOperation<>(operator, getLiteral(value)));
+  }
+
   /**
    * Create Typed JsonLiteral object for the value
    *

src/main/java/io/stargate/sgv3/docsapi/api/model/command/clause/filter/ValueComparisonOperator.java

@@ -1,11 +1,42 @@
 package io.stargate.sgv3.docsapi.api.model.command.clause.filter;
 
-/** List of value operator that can be used in Filter clause */
+import io.stargate.sgv3.docsapi.exception.DocsException;
+import io.stargate.sgv3.docsapi.exception.ErrorCode;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * List of value operator that can be used in Filter clause Have commented the unsupported
+ * operators, will add it as we support them
+ */
 public enum ValueComparisonOperator implements FilterOperator {
-  EQ,
-  GT,
-  GTE,
-  LT,
-  LTE,
-  NE
+  EQ("$eq");
+  /*GT("$gt"),
+  GTE("$gte"),
+  LT("$lt"),
+  LTE("$lte"),
+  NE("$ne");*/
+
+  private String operator;
+
+  ValueComparisonOperator(String operator) {
+    this.operator = operator;
+  }
+
+  private static final Map<String, ValueComparisonOperator> operatorMap = new HashMap<>();
+
+  static {
+    for (ValueComparisonOperator filterOperator : ValueComparisonOperator.values()) {
+      operatorMap.put(filterOperator.operator, filterOperator);
+    }
+  }
+
+  public static ValueComparisonOperator getComparisonOperator(String operator) {
+    final ValueComparisonOperator valueComparisonOperator = operatorMap.get(operator);
+    if (valueComparisonOperator == null)
+      throw new DocsException(
+          ErrorCode.UNSUPPORTED_FILTER_OPERATION, "Unsupported filter operation " + operator);
+
+    return valueComparisonOperator;
+  }
 }

src/main/java/io/stargate/sgv3/docsapi/api/model/command/deserializers/FilterClauseDeserializer.java

@@ -7,6 +7,7 @@
 import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
 import io.stargate.sgv3.docsapi.api.model.command.clause.filter.ComparisonExpression;
 import io.stargate.sgv3.docsapi.api.model.command.clause.filter.FilterClause;
+import io.stargate.sgv3.docsapi.api.model.command.clause.filter.ValueComparisonOperator;
 import io.stargate.sgv3.docsapi.exception.DocsException;
 import io.stargate.sgv3.docsapi.exception.ErrorCode;
 import java.io.IOException;
@@ -22,7 +23,10 @@ public FilterClauseDeserializer() {
     super(FilterClause.class);
   }
 
-  /** {@inheritDoc} */
+  /**
+   * {@inheritDoc} Filter clause can follow short cut {"field" : "value"} instead of {"field" :
+   * {"$eq" : "value"}}
+   */
   @Override
   public FilterClause deserialize(
       JsonParser jsonParser, DeserializationContext deserializationContext)
@@ -35,13 +39,42 @@ public FilterClause deserialize(
       Map.Entry<String, JsonNode> entry = fieldIter.next();
       // TODO: Does not handle logical expressions, they are out of scope
       JsonNode operatorExpression = entry.getValue();
-      if (!operatorExpression.isValueNode())
-        throw new DocsException(ErrorCode.UNSUPPORTED_FILTER_DATA_TYPE);
-      expressionList.add(ComparisonExpression.eq(entry.getKey(), jsonNodeValue(entry.getValue())));
+      if (operatorExpression.isObject()) {
+        expressionList.add(createComparisonExpression(entry));
+      } else {
+        // @TODO: Need to add array value type to this condition
+        expressionList.add(
+            ComparisonExpression.eq(entry.getKey(), jsonNodeValue(entry.getValue())));
+      }
     }
     return new FilterClause(expressionList);
   }
 
+  /**
+   * The filter clause is entry will have field path as key and object type as value. The value can
+   * have multiple operator and condition values.
+   *
+   * <p>Eg 1: {"field" : {"$eq" : "value"}}
+   *
+   * <p>Eg 2: {"field" : {"$gt" : 10, "$lt" : 50}}
+   *
+   * @param entry
+   * @return
+   */
+  private ComparisonExpression createComparisonExpression(Map.Entry<String, JsonNode> entry) {
+    ComparisonExpression expression = new ComparisonExpression(entry.getKey(), new ArrayList<>());
+    final Iterator<Map.Entry<String, JsonNode>> fields = entry.getValue().fields();
+    while (fields.hasNext()) {
+      Map.Entry<String, JsonNode> updateField = fields.next();
+      ValueComparisonOperator operator =
+          ValueComparisonOperator.getComparisonOperator(updateField.getKey());
+      JsonNode value = updateField.getValue();
+      // @TODO: Need to add array and sub-document value type to this condition
+      expression.add(operator, jsonNodeValue(value));
+    }
+    return expression;
+  }
+
   private static Object jsonNodeValue(JsonNode node) {
     switch (node.getNodeType()) {
       case BOOLEAN:

src/main/java/io/stargate/sgv3/docsapi/service/resolver/model/impl/matcher/FilterMatchRules.java

@@ -64,7 +64,11 @@ public ReadOperation apply(CommandContext commandContext, T command) {
         .filter(Optional::isPresent)
         .map(Optional::get) // unwraps the Optional from the resolver function.
         .findFirst()
-        .orElseThrow(() -> new DocsException(ErrorCode.FILTER_UNRESOLVABLE));
+        .orElseThrow(
+            () ->
+                new DocsException(
+                    ErrorCode.FILTER_UNRESOLVABLE,
+                    "Filter type not supported, unable to resolve to a filtering strategy"));
   }
 
   @VisibleForTesting

src/test/java/io/stargate/sgv3/docsapi/api/model/command/clause/filter/ComparisonExpressionTest.java

@@ -3,6 +3,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import java.math.BigDecimal;
+import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.List;
 import org.junit.jupiter.api.Nested;
@@ -26,6 +27,20 @@ public void stringValueComparisonExpression() throws Exception {
       assertThat(result).isEqualTo(expectedResult);
     }
 
+    @Test
+    public void multiValueComparisonExpression() throws Exception {
+      final ComparisonExpression expectedResult =
+          new ComparisonExpression(
+              "username",
+              List.of(
+                  new ValueComparisonOperation(
+                      ValueComparisonOperator.EQ, new JsonLiteral("abc", JsonType.STRING))));
+
+      ComparisonExpression result = new ComparisonExpression("username", new ArrayList<>());
+      result.add(ValueComparisonOperator.EQ, "abc");
+      assertThat(result).isEqualTo(expectedResult);
+    }
+
     @Test
     public void numberValueComparisonExpression() throws Exception {
       final ComparisonExpression expectedResult =
@@ -95,10 +110,6 @@ public void matchTest() throws Exception {
           comparisonExpression.match(
               "path", EnumSet.of(ValueComparisonOperator.EQ), JsonType.STRING);
       assertThat(match).hasSize(0);
-
-      match =
-          comparisonExpression.match("path", EnumSet.of(ValueComparisonOperator.GT), JsonType.NULL);
-      assertThat(match).hasSize(0);
     }
   }
 }

src/test/java/io/stargate/sgv3/docsapi/api/model/command/deserializers/FilterClauseDeserializerTest.java

@@ -46,6 +46,23 @@ public void happyPath() throws Exception {
       assertThat(filterClause.comparisonExpressions()).hasSize(1).contains(expectedResult);
     }
 
+    @Test
+    public void eqComparisonOperator() throws Exception {
+      String json = """
+                    {"username": {"$eq" : "aaron"}}
+                    """;
+
+      FilterClause filterClause = objectMapper.readValue(json, FilterClause.class);
+      final ComparisonExpression expectedResult =
+          new ComparisonExpression(
+              "username",
+              List.of(
+                  new ValueComparisonOperation(
+                      ValueComparisonOperator.EQ, new JsonLiteral("aaron", JsonType.STRING))));
+      assertThat(filterClause).isNotNull();
+      assertThat(filterClause.comparisonExpressions()).hasSize(1).contains(expectedResult);
+    }
+
     @Test
     public void mustHandleNull() throws Exception {
       String json = "null";

src/test/java/io/stargate/sgv3/docsapi/api/v3/FindIntegrationTest.java

@@ -5,6 +5,7 @@
 import static net.javacrumbs.jsonunit.JsonMatchers.jsonEquals;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.startsWith;
 
 import io.quarkus.test.junit.QuarkusIntegrationTest;
 import io.restassured.http.ContentType;
@@ -137,6 +138,7 @@ public void findById() {
           .post(CollectionResource.BASE_PATH, keyspaceId.asInternal(), collectionName)
           .then()
           .statusCode(200)
+          .body("data.count", is(1))
           .body("data.docs[0]", jsonEquals(expected));
     }
 
@@ -160,9 +162,56 @@ public void findByColumn() {
           .post(CollectionResource.BASE_PATH, keyspaceId.asInternal(), collectionName)
           .then()
           .statusCode(200)
+          .body("data.count", is(1))
           .body("data.docs[0]", jsonEquals(expected));
     }
 
+    @Test
+    @Order(2)
+    public void findWithEqComparisonOperator() {
+      String json =
+          """
+          {
+            "find": {
+              "filter" : {"username" : {"$eq" : "user1"}}
+            }
+          }
+          """;
+      String expected = "{\"_id\":\"doc1\", \"username\":\"user1\", \"active_user\":true}";
+      given()
+          .header(HttpConstants.AUTHENTICATION_TOKEN_HEADER_NAME, getAuthToken())
+          .contentType(ContentType.JSON)
+          .body(json)
+          .when()
+          .post(CollectionResource.BASE_PATH, keyspaceId.asInternal(), collectionName)
+          .then()
+          .statusCode(200)
+          .body("data.count", is(1))
+          .body("data.docs[0]", jsonEquals(expected));
+    }
+
+    @Test
+    @Order(2)
+    public void findWithNEComparisonOperator() {
+      String json =
+          """
+              {
+                "find": {
+                  "filter" : {"username" : {"$ne" : "user1"}}
+                }
+              }
+              """;
+      given()
+          .header(HttpConstants.AUTHENTICATION_TOKEN_HEADER_NAME, getAuthToken())
+          .contentType(ContentType.JSON)
+          .body(json)
+          .when()
+          .post(CollectionResource.BASE_PATH, keyspaceId.asInternal(), collectionName)
+          .then()
+          .statusCode(200)
+          .body("errors[1].message", startsWith("Unsupported filter operation $ne"));
+    }
+
     @Test
     @Order(2)
     public void findByBooleanColumn() {
@@ -280,6 +329,7 @@ public void findOneById() {
           .post(CollectionResource.BASE_PATH, keyspaceId.asInternal(), collectionName)
           .then()
           .statusCode(200)
+          .body("data.count", is(1))
           .body("data.docs[0]", jsonEquals(expected));
     }
 
@@ -303,6 +353,7 @@ public void findOneByColumn() {
           .post(CollectionResource.BASE_PATH, keyspaceId.asInternal(), collectionName)
           .then()
           .statusCode(200)
+          .body("data.count", is(1))
           .body("data.docs[0]", jsonEquals(expected));
     }
   }