Count command implementation

src/main/java/io/stargate/sgv2/jsonapi/StargateJsonApi.java

@@ -70,6 +70,17 @@
                         }
                       }
                       """),
+              @ExampleObject(
+                  name = "countDocuments",
+                  summary = "`countDocuments` command",
+                  value =
+                      """
+                            {
+                              "countDocuments": {
+                                  "filter": {"location": "London", "race.competitors" : {"$eq" : 100}}
+                              }
+                            }
+                            """),
               @ExampleObject(
                   name = "find",
                   summary = "`find` command",
@@ -209,6 +220,17 @@
                                 }
                             }
                             """),
+              @ExampleObject(
+                  name = "resultCount",
+                  summary = "countDocuments command result",
+                  value =
+                      """
+                                    {
+                                      "status": {
+                                        "counted_documents": 2
+                                      }
+                                    }
+                                    """),
               @ExampleObject(
                   name = "resultRead",
                   summary = "Read command result",

src/main/java/io/stargate/sgv2/jsonapi/api/model/command/Command.java

@@ -2,6 +2,7 @@
 
 import com.fasterxml.jackson.annotation.JsonSubTypes;
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import io.stargate.sgv2.jsonapi.api.model.command.impl.CountDocumentsCommands;
 import io.stargate.sgv2.jsonapi.api.model.command.impl.CreateCollectionCommand;
 import io.stargate.sgv2.jsonapi.api.model.command.impl.CreateNamespaceCommand;
 import io.stargate.sgv2.jsonapi.api.model.command.impl.DeleteOneCommand;
@@ -34,6 +35,7 @@
     include = JsonTypeInfo.As.WRAPPER_OBJECT,
     property = "commandName")
 @JsonSubTypes({
+  @JsonSubTypes.Type(value = CountDocumentsCommands.class),
   @JsonSubTypes.Type(value = CreateNamespaceCommand.class),
   @JsonSubTypes.Type(value = CreateCollectionCommand.class),
   @JsonSubTypes.Type(value = DeleteOneCommand.class),

src/main/java/io/stargate/sgv2/jsonapi/api/model/command/CommandStatus.java

@@ -2,13 +2,21 @@
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+/** Enum with it's json property name which is returned in api response inside status */
 public enum CommandStatus {
+  /** The element has the count of document */
+  @JsonProperty("counted_documents")
+  COUNTED_DOCUMENT,
+  /** The element has the list of deleted ids */
   @JsonProperty("deletedIds")
   DELETED_IDS,
+  /** The element has the list of inserted ids */
   @JsonProperty("insertedIds")
   INSERTED_IDS,
+  /** The element has value 1 if collection is created */
   @JsonProperty("ok")
   OK,
+  /** The element has the list of updated ids */
   @JsonProperty("updatedIds")
   UPDATED_IDS;
 }

src/main/java/io/stargate/sgv2/jsonapi/api/model/command/impl/CountDocumentsCommands.java

@@ -0,0 +1,21 @@
+package io.stargate.sgv2.jsonapi.api.model.command.impl;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import io.stargate.sgv2.jsonapi.api.model.command.Filterable;
+import io.stargate.sgv2.jsonapi.api.model.command.ReadCommand;
+import io.stargate.sgv2.jsonapi.api.model.command.clause.filter.FilterClause;
+import javax.annotation.Nullable;
+import javax.validation.Valid;
+import org.eclipse.microprofile.openapi.annotations.media.Schema;
+
+@Schema(
+    description =
+        "Command that returns count of documents in a collection based on the collection.")
+@JsonTypeName("countDocuments")
+public record CountDocumentsCommands(
+    @Valid @JsonProperty("filter") FilterClause filterClause, @Valid @Nullable Options options)
+    implements ReadCommand, Filterable {
+
+  public record Options() {}
+}

src/main/java/io/stargate/sgv2/jsonapi/api/v1/CollectionResource.java

@@ -4,6 +4,7 @@
 import io.stargate.sgv2.jsonapi.api.model.command.CollectionCommand;
 import io.stargate.sgv2.jsonapi.api.model.command.CommandContext;
 import io.stargate.sgv2.jsonapi.api.model.command.CommandResult;
+import io.stargate.sgv2.jsonapi.api.model.command.impl.CountDocumentsCommands;
 import io.stargate.sgv2.jsonapi.api.model.command.impl.DeleteOneCommand;
 import io.stargate.sgv2.jsonapi.api.model.command.impl.FindCommand;
 import io.stargate.sgv2.jsonapi.api.model.command.impl.FindOneAndUpdateCommand;
@@ -66,6 +67,7 @@ public CollectionResource(CommandProcessor commandProcessor) {
               schema =
                   @Schema(
                       anyOf = {
+                        CountDocumentsCommands.class,
                         DeleteOneCommand.class,
                         FindOneCommand.class,
                         FindCommand.class,
@@ -75,6 +77,7 @@ public CollectionResource(CommandProcessor commandProcessor) {
                         UpdateOneCommand.class
                       }),
               examples = {
+                @ExampleObject(ref = "count"),
                 @ExampleObject(ref = "deleteOne"),
                 @ExampleObject(ref = "findOne"),
                 @ExampleObject(ref = "find"),
@@ -93,6 +96,7 @@ public CollectionResource(CommandProcessor commandProcessor) {
                   mediaType = MediaType.APPLICATION_JSON,
                   schema = @Schema(implementation = CommandResult.class),
                   examples = {
+                    @ExampleObject(ref = "resultCount"),
                     @ExampleObject(ref = "resultRead"),
                     @ExampleObject(ref = "resultFindOneAndUpdate"),
                     @ExampleObject(ref = "resultInsert"),

src/main/java/io/stargate/sgv2/jsonapi/exception/ErrorCode.java

@@ -26,6 +26,8 @@ public enum ErrorCode {
 
   UNSUPPORTED_FILTER_OPERATION("Unsupported filter operator"),
 
+  UNSUPPORTED_OPERATION("Unsupported operation class"),
+
   UNSUPPORTED_UPDATE_DATA_TYPE("Unsupported update data type"),
 
   UNSUPPORTED_UPDATE_OPERATION("Unsupported update operation"),

src/main/java/io/stargate/sgv2/jsonapi/service/operation/model/CountOperation.java

@@ -0,0 +1,51 @@
+package io.stargate.sgv2.jsonapi.service.operation.model;
+
+import io.smallrye.mutiny.Uni;
+import io.stargate.bridge.proto.QueryOuterClass;
+import io.stargate.sgv2.api.common.cql.builder.BuiltCondition;
+import io.stargate.sgv2.api.common.cql.builder.QueryBuilder;
+import io.stargate.sgv2.jsonapi.api.model.command.CommandContext;
+import io.stargate.sgv2.jsonapi.api.model.command.CommandResult;
+import io.stargate.sgv2.jsonapi.exception.ErrorCode;
+import io.stargate.sgv2.jsonapi.exception.JsonApiException;
+import io.stargate.sgv2.jsonapi.service.bridge.executor.QueryExecutor;
+import io.stargate.sgv2.jsonapi.service.operation.model.impl.CountOperationPage;
+import io.stargate.sgv2.jsonapi.service.operation.model.impl.DBFilterBase;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Supplier;
+
+/**
+ * Operation that returns count of documents based on the filter condition. Written with the
+ * assumption that all variables to be indexed.
+ */
+public record CountOperation(CommandContext commandContext, List<DBFilterBase> filters)
+    implements ReadOperation {
+
+  @Override
+  public Uni<Supplier<CommandResult>> execute(QueryExecutor queryExecutor) {
+    QueryOuterClass.Query query = buildSelectQuery();
+    return countDocuments(queryExecutor, query)
+        .onItem()
+        .transform(docs -> new CountOperationPage(docs.count()));
+  }
+
+  private QueryOuterClass.Query buildSelectQuery() {
+    List<BuiltCondition> conditions = new ArrayList<>(filters.size());
+    for (DBFilterBase filter : filters) {
+      conditions.add(filter.get());
+    }
+    return new QueryBuilder()
+        .select()
+        .count("key")
+        .as("count")
+        .from(commandContext.namespace(), commandContext.collection())
+        .where(conditions)
+        .build();
+  }
+
+  @Override
+  public Uni<FindResponse> getDocuments(QueryExecutor queryExecutor) {
+    return Uni.createFrom().failure(new JsonApiException(ErrorCode.UNSUPPORTED_OPERATION));
+  }
+}

src/main/java/io/stargate/sgv2/jsonapi/service/operation/model/ReadOperation.java

@@ -21,8 +21,8 @@
  * implementation to excute and query and parse the result set as {@link FindResponse}
  */
 public interface ReadOperation extends Operation {
-  static String[] documentColumns = {"key", "tx_id", "doc_json"};
-  static String[] documentKeyColumns = {"key", "tx_id"};
+  String[] documentColumns = {"key", "tx_id", "doc_json"};
+  String[] documentKeyColumns = {"key", "tx_id"};
 
   /**
    * Default implementation to query and parse the result set
@@ -90,6 +90,26 @@ private String extractPagingStateFromResultSet(QueryOuterClass.ResultSet rSet) {
     }
     return null;
   }
+  /**
+   * Default implementation to run count query and parse the result set
+   *
+   * @param queryExecutor
+   * @param query
+   * @return
+   */
+  default Uni<CountResponse> countDocuments(
+      QueryExecutor queryExecutor, QueryOuterClass.Query query) {
+    return queryExecutor
+        .executeRead(query, Optional.empty(), 1)
+        .onItem()
+        .transform(
+            rSet -> {
+              QueryOuterClass.Row row = rSet.getRows(0); // For count there will be only one row
+              int count =
+                  Values.int_(row.getValues(0)); // Count value will be the first column value
+              return new CountResponse(count);
+            });
+  }
 
   /**
    * A operation method which can return FindResponse instead of CommandResult. This method will be
@@ -100,5 +120,7 @@ private String extractPagingStateFromResultSet(QueryOuterClass.ResultSet rSet) {
    */
   Uni<FindResponse> getDocuments(QueryExecutor queryExecutor);
 
-  public static record FindResponse(List<ReadDocument> docs, String pagingState) {}
+  record FindResponse(List<ReadDocument> docs, String pagingState) {}
+
+  record CountResponse(int count) {}
 }

src/main/java/io/stargate/sgv2/jsonapi/service/operation/model/ReadType.java

@@ -0,0 +1,19 @@
+package io.stargate.sgv2.jsonapi.service.operation.model;
+
+/**
+ * Read type specifies what data needs to be read and returned as part of the response for
+ * operations
+ */
+public enum ReadType {
+  /**
+   * Return documents and transaction id which satisfies the filter conditions as part of response
+   */
+  DOCUMENT,
+  /**
+   * Return only document id and transaction id of documents which satisfies the filter conditions
+   * as part of response
+   */
+  KEY,
+  /** Return only count of documents which satisfies the filter condition */
+  COUNT
+}

src/main/java/io/stargate/sgv2/jsonapi/service/operation/model/impl/CountOperationPage.java

@@ -0,0 +1,13 @@
+package io.stargate.sgv2.jsonapi.service.operation.model.impl;
+
+import io.stargate.sgv2.jsonapi.api.model.command.CommandResult;
+import io.stargate.sgv2.jsonapi.api.model.command.CommandStatus;
+import java.util.Map;
+import java.util.function.Supplier;
+
+public record CountOperationPage(int count) implements Supplier<CommandResult> {
+  @Override
+  public CommandResult get() {
+    return new CommandResult(Map.of(CommandStatus.COUNTED_DOCUMENT, count()));
+  }
+}

src/main/java/io/stargate/sgv2/jsonapi/service/operation/model/impl/FindOperation.java

@@ -7,25 +7,23 @@
 import io.stargate.sgv2.api.common.cql.builder.QueryBuilder;
 import io.stargate.sgv2.jsonapi.api.model.command.CommandContext;
 import io.stargate.sgv2.jsonapi.api.model.command.CommandResult;
+import io.stargate.sgv2.jsonapi.exception.ErrorCode;
+import io.stargate.sgv2.jsonapi.exception.JsonApiException;
 import io.stargate.sgv2.jsonapi.service.bridge.executor.QueryExecutor;
 import io.stargate.sgv2.jsonapi.service.operation.model.ReadOperation;
+import io.stargate.sgv2.jsonapi.service.operation.model.ReadType;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Supplier;
 
-/**
- * Full dynamic query generation for any of the types of filtering we can do against the the db
- * table.
- *
- * <p>Create with a series of filters that are implicitly AND'd together.
- */
+/** Operation that returns the documents or its key based on the filter condition. */
 public record FindOperation(
     CommandContext commandContext,
     List<DBFilterBase> filters,
     String pagingState,
     int limit,
     int pageSize,
-    boolean readDocument,
+    ReadType readType,
     ObjectMapper objectMapper)
     implements ReadOperation {
 
@@ -38,8 +36,23 @@ public Uni<Supplier<CommandResult>> execute(QueryExecutor queryExecutor) {
 
   @Override
   public Uni<FindResponse> getDocuments(QueryExecutor queryExecutor) {
-    QueryOuterClass.Query query = buildSelectQuery();
-    return findDocument(queryExecutor, query, pagingState, pageSize, readDocument, objectMapper);
+    switch (readType) {
+      case DOCUMENT:
+      case KEY:
+        {
+          QueryOuterClass.Query query = buildSelectQuery();
+          return findDocument(
+              queryExecutor,
+              query,
+              pagingState,
+              pageSize,
+              ReadType.DOCUMENT == readType,
+              objectMapper);
+        }
+      default:
+        throw new JsonApiException(
+            ErrorCode.UNSUPPORTED_OPERATION, "Unsupported find operation read type " + readType);
+    }
   }
 
   private QueryOuterClass.Query buildSelectQuery() {
@@ -49,7 +62,7 @@ private QueryOuterClass.Query buildSelectQuery() {
     }
     return new QueryBuilder()
         .select()
-        .column(readDocument ? documentColumns : documentKeyColumns)
+        .column(ReadType.DOCUMENT == readType ? documentColumns : documentKeyColumns)
         .from(commandContext.namespace(), commandContext.collection())
         .where(conditions)
         .limit(limit)

src/main/java/io/stargate/sgv2/jsonapi/service/operation/model/impl/ReadOperationPage.java

@@ -9,7 +9,6 @@
 /** FindOperation response implementing the {@link CommandResult} */
 public record ReadOperationPage(List<ReadDocument> docs, String pagingState)
     implements Supplier<CommandResult> {
-
   @Override
   public CommandResult get() {
     final List<JsonNode> jsonNodes = new ArrayList<>();

src/main/java/io/stargate/sgv2/jsonapi/service/resolver/model/impl/CountDocumentsCommandResolver.java

@@ -0,0 +1,36 @@
+package io.stargate.sgv2.jsonapi.service.resolver.model.impl;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.stargate.sgv2.jsonapi.api.model.command.CommandContext;
+import io.stargate.sgv2.jsonapi.api.model.command.impl.CountDocumentsCommands;
+import io.stargate.sgv2.jsonapi.service.operation.model.Operation;
+import io.stargate.sgv2.jsonapi.service.operation.model.ReadType;
+import io.stargate.sgv2.jsonapi.service.resolver.model.CommandResolver;
+import io.stargate.sgv2.jsonapi.service.resolver.model.impl.matcher.FilterableResolver;
+import javax.enterprise.context.ApplicationScoped;
+import javax.inject.Inject;
+
+/** Resolves the {@link CountDocumentsCommands } */
+@ApplicationScoped
+public class CountDocumentsCommandResolver extends FilterableResolver<CountDocumentsCommands>
+    implements CommandResolver<CountDocumentsCommands> {
+  @Inject
+  public CountDocumentsCommandResolver(ObjectMapper objectMapper) {
+    super(objectMapper);
+  }
+
+  @Override
+  public Class<CountDocumentsCommands> getCommandClass() {
+    return CountDocumentsCommands.class;
+  }
+
+  @Override
+  public Operation resolveCommand(CommandContext ctx, CountDocumentsCommands command) {
+    return resolve(ctx, command);
+  }
+
+  @Override
+  protected FilteringOptions getFilteringOption(CountDocumentsCommands command) {
+    return new FilteringOptions(Integer.MAX_VALUE, null, 1, ReadType.COUNT);
+  }
+}