Add StringType proxy class

matlab/src/cpp/arrow/matlab/proxy/factory.cc

@@ -22,6 +22,7 @@
 #include "arrow/matlab/tabular/proxy/record_batch.h"
 #include "arrow/matlab/error/error.h"
 #include "arrow/matlab/type/proxy/primitive_ctype.h"
+#include "arrow/matlab/type/proxy/string_type.h"
 #include "arrow/matlab/type/proxy/timestamp_type.h"
 
 #include "factory.h"
@@ -54,6 +55,7 @@ libmexclass::proxy::MakeResult Factory::make_proxy(const ClassName& class_name,
     REGISTER_PROXY(arrow.type.proxy.Int32Type      , arrow::matlab::type::proxy::PrimitiveCType<int32_t>);
     REGISTER_PROXY(arrow.type.proxy.Int64Type      , arrow::matlab::type::proxy::PrimitiveCType<int64_t>);
     REGISTER_PROXY(arrow.type.proxy.BooleanType    , arrow::matlab::type::proxy::PrimitiveCType<bool>);
+    REGISTER_PROXY(arrow.type.proxy.StringType  , arrow::matlab::type::proxy::StringType);
     REGISTER_PROXY(arrow.type.proxy.TimestampType  , arrow::matlab::type::proxy::TimestampType);
 
     return libmexclass::error::Error{error::UNKNOWN_PROXY_ERROR_ID, "Did not find matching C++ proxy for " + class_name};

matlab/src/cpp/arrow/matlab/type/proxy/string_type.cc

@@ -0,0 +1,27 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/matlab/type/proxy/string_type.h"
+
+namespace arrow::matlab::type::proxy {
+
+    StringType::StringType(std::shared_ptr<arrow::StringType> string_type) : Type(string_type) {}
+
+    libmexclass::proxy::MakeResult StringType::make(const libmexclass::proxy::FunctionArguments& constructor_arguments) {
+        return std::make_shared<StringType>(std::static_pointer_cast<arrow::StringType>(arrow::utf8()));
+    }
+}

matlab/src/cpp/arrow/matlab/type/proxy/string_type.h

@@ -0,0 +1,35 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include "arrow/matlab/type/proxy/type.h"
+
+namespace arrow::matlab::type::proxy {
+
+class StringType : public arrow::matlab::type::proxy::Type {
+
+    public:
+        StringType(std::shared_ptr<arrow::StringType> string_type);
+
+        ~StringType() {}
+
+        static libmexclass::proxy::MakeResult make(const libmexclass::proxy::FunctionArguments& constructor_arguments);
+};
+
+}
+

matlab/src/matlab/+arrow/+type/StringType.m

@@ -16,14 +16,10 @@
 classdef StringType < arrow.type.Type
 %STRINGTYPE Type class for string data.
 
-    properties(SetAccess = protected)
-        ID = arrow.type.ID.String
-    end
-
-    properties(Constant)
-        NumFields = 0
-        NumBuffers = 3
-    end
-
+    methods
+        function obj = StringType()
+            obj@arrow.type.Type("Name", "arrow.type.proxy.StringType", "ConstructorArguments", {});
+        end
+   end
 end
 

matlab/test/arrow/array/tStringArray.m

@@ -149,7 +149,7 @@ function TestArrowType(tc)
             % Verify the array has the expected arrow.type.Type object
             data = tc.MatlabArrayFcn(["A", "B"]);
             arrowArray = tc.ArrowArrayConstructor(data);
-            tc.verifyEqual(arrowArray.Type, tc.ArrowType);
+            tc.verifyEqual(arrowArray.Type.ID, tc.ArrowType.ID);
         end
 
         function Unicode(tc)

matlab/test/arrow/type/tStringType.m

@@ -25,14 +25,9 @@ function Basic(tc)
             tc.verifyEqual(type.ID, arrow.type.ID.String);
         end
 
-        function NumBuffers(tc)
-            type = arrow.type.StringType;
-            tc.verifyEqual(type.NumBuffers, 3);
-        end
-
         function NumFields(tc)
             type = arrow.type.StringType;
-            tc.verifyEqual(type.NumFields, 0);
+            tc.verifyEqual(type.NumFields, int32(0));
         end
 
     end

matlab/tools/cmake/BuildMatlabArrowInterface.cmake

@@ -51,6 +51,7 @@ set(MATLAB_ARROW_LIBMEXCLASS_CLIENT_PROXY_SOURCES "${CMAKE_SOURCE_DIR}/src/cpp/a
                                                   "${CMAKE_SOURCE_DIR}/src/cpp/arrow/matlab/type/time_unit.cc"
                                                   "${CMAKE_SOURCE_DIR}/src/cpp/arrow/matlab/type/proxy/type.cc"
                                                   "${CMAKE_SOURCE_DIR}/src/cpp/arrow/matlab/type/proxy/fixed_width_type.cc"
+                                                  "${CMAKE_SOURCE_DIR}/src/cpp/arrow/matlab/type/proxy/string_type.cc"
                                                   "${CMAKE_SOURCE_DIR}/src/cpp/arrow/matlab/type/proxy/timestamp_type.cc")
 
 set(MATLAB_ARROW_LIBMEXCLASS_CLIENT_PROXY_FACTORY_INCLUDE_DIR "${CMAKE_SOURCE_DIR}/src/cpp/arrow/matlab/proxy")