THRIFT-5544: annotations_as_metadata java code gen param (#2553)

Add a java code generation parameter called "annotations_as_metadata" to
optionally include Thrift field annotations as metadata in the generated code.

5 files changed, 170 insertions, 11 deletions

diff --git a/compiler/cpp/src/thrift/generate/t_java_generator.cc b/compiler/cpp/src/thrift/generate/t_java_generator.cc
index a875c9b62..3ce1450b1 100644
--- a/compiler/cpp/src/thrift/generate/t_java_generator.cc
+++ b/compiler/cpp/src/thrift/generate/t_java_generator.cc
@@ -78,6 +78,7 @@ public:
     suppress_generated_annotations_ = false;
     rethrow_unhandled_exceptions_ = false;
     unsafe_binaries_ = false;
+    annotations_as_metadata_ = false;
     for (iter = parsed_options.begin(); iter != parsed_options.end(); ++iter) {
       if (iter->first.compare("beans") == 0) {
         bean_style_ = true;
@@ -124,6 +125,8 @@ public:
         }
       } else if (iter->first.compare("unsafe_binaries") == 0) {
         unsafe_binaries_ = true;
+      } else if (iter->first.compare("annotations_as_metadata") == 0) {
+        annotations_as_metadata_ = true;
       } else {
         throw "unknown option java:" + iter->first;
       }
@@ -188,6 +191,7 @@ public:
   void generate_java_struct_read_object(std::ostream& out, t_struct* tstruct);
   void generate_java_meta_data_map(std::ostream& out, t_struct* tstruct);
   void generate_field_value_meta_data(std::ostream& out, t_type* type);
+  void generate_metadata_for_field_annotations(std::ostream& out, t_field* field);
   std::string get_java_type_string(t_type* type);
   void generate_java_struct_field_by_id(ostream& out, t_struct* tstruct);
   void generate_reflection_setters(std::ostringstream& out,
@@ -439,6 +443,7 @@ private:
   bool suppress_generated_annotations_;
   bool rethrow_unhandled_exceptions_;
   bool unsafe_binaries_;
+  bool annotations_as_metadata_;
 };
 
 /**
@@ -2856,6 +2861,11 @@ void t_java_generator::generate_java_meta_data_map(ostream& out, t_struct* tstru
 
     // Create value meta data
     generate_field_value_meta_data(out, field->get_type());
+
+    // Include the annotation into metadata when asked
+    if (annotations_as_metadata_) {
+      generate_metadata_for_field_annotations(out, field);
+    }
     out << "));" << endl;
   }
 
@@ -2924,6 +2934,33 @@ std::string t_java_generator::get_java_type_string(t_type* type) {
   }
 }
 
+void t_java_generator::generate_metadata_for_field_annotations(std::ostream& out, t_field* field) {
+  if (field->annotations_.size() == 0) {
+    return;
+  }
+  out << ", " << endl;
+  indent_up();
+  indent_up();
+  indent(out) << "java.util.stream.Stream.<java.util.Map.Entry<java.lang.String, "
+                 "java.lang.String>>builder()"
+              << endl;
+
+  indent_up();
+  indent_up();
+  for (auto& annotation : field->annotations_) {
+    indent(out) << ".add(new java.util.AbstractMap.SimpleImmutableEntry<>(\"" + annotation.first
+                       + "\", \"" + annotation.second + "\"))"
+                << endl;
+  }
+  indent(out) << ".build().collect(java.util.stream.Collectors.toMap(java.util.Map.Entry::getKey, "
+                 "java.util.Map.Entry::getValue))";
+  indent_down();
+  indent_down();
+
+  indent_down();
+  indent_down();
+}
+
 void t_java_generator::generate_field_value_meta_data(std::ostream& out, t_type* type) {
   out << endl;
   indent_up();
@@ -5740,4 +5777,6 @@ THRIFT_REGISTER_GENERATOR(
     "    generated_annotations=[undated|suppress]:\n"
     "                     undated: suppress the date at @Generated annotations\n"
     "                     suppress: suppress @Generated annotations entirely\n"
-    "    unsafe_binaries: Do not copy ByteBuffers in constructors, getters, and setters.\n")
+    "    unsafe_binaries: Do not copy ByteBuffers in constructors, getters, and setters.\n"
+    "    annotations_as_metadata:\n"
+    "                     Include Thrift field annotations as metadata in the generated code.\n")
diff --git a/lib/java/gradle/generateTestThrift.gradle b/lib/java/gradle/generateTestThrift.gradle
index b8a963d12..e8515473e 100644
--- a/lib/java/gradle/generateTestThrift.gradle
+++ b/lib/java/gradle/generateTestThrift.gradle
@@ -86,6 +86,7 @@ task generateJava(group: 'Build') {
     thriftCompile(it, 'EnumContainersTest.thrift')
     thriftCompile(it, 'JavaBinaryDefault.thrift')
     thriftCompile(it, 'VoidMethExceptionsTest.thrift')
+    thriftCompile(it, 'AnnotationTest.thrift')
     thriftCompile(it, 'partial/thrift_test_schema.thrift')
 }
 
@@ -133,3 +134,12 @@ task generateUnsafeBinariesJava(group: 'Build') {
 
     thriftCompile(it, 'UnsafeTypes.thrift', 'java:unsafe_binaries', genUnsafeSrc)
 }
+
+task generateWithAnnotationMetadata(group: 'Build') {
+    description = 'Generate with annotation enabled and add to the default source'
+    generate.dependsOn it
+
+    ext.outputBuffer = new ByteArrayOutputStream()
+
+    thriftCompile(it, 'JavaAnnotationTest.thrift', 'java:annotations_as_metadata', genSrc)
+}
diff --git a/lib/java/src/main/java/org/apache/thrift/meta_data/FieldMetaData.java b/lib/java/src/main/java/org/apache/thrift/meta_data/FieldMetaData.java
index 753439045..5691f83e6 100644
--- a/lib/java/src/main/java/org/apache/thrift/meta_data/FieldMetaData.java
+++ b/lib/java/src/main/java/org/apache/thrift/meta_data/FieldMetaData.java
@@ -19,9 +19,14 @@
 
 package org.apache.thrift.meta_data;
 
+import java.util.AbstractMap;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.apache.thrift.TBase;
 import org.apache.thrift.TFieldIdEnum;
@@ -42,18 +47,28 @@ public class FieldMetaData implements java.io.Serializable {
   public final String fieldName;
   public final byte requirementType;
   public final FieldValueMetaData valueMetaData;
-  private static final Map<Class<? extends TBase>, Map<? extends TFieldIdEnum, FieldMetaData>> structMap;
-  
-  static {
-    structMap = new ConcurrentHashMap<Class<? extends TBase>, Map<? extends TFieldIdEnum, FieldMetaData>>();
-  }
-  
+  private final Map<String, String> fieldAnnotations;
+  private static final Map<Class<? extends TBase>, Map<? extends TFieldIdEnum, FieldMetaData>> structMap = new ConcurrentHashMap<>();
+
   public FieldMetaData(String name, byte req, FieldValueMetaData vMetaData){
-    this.fieldName = name;
-    this.requirementType = req;
-    this.valueMetaData = vMetaData;
+    this(name, req, vMetaData, Collections.emptyMap());
   }
-  
+
+  public FieldMetaData(String fieldName, byte requirementType, FieldValueMetaData valueMetaData, Map<String, String> fieldAnnotations) {
+    this.fieldName = fieldName;
+    this.requirementType = requirementType;
+    this.valueMetaData = valueMetaData;
+    this.fieldAnnotations = fieldAnnotations;
+  }
+
+  /**
+   * @return an unmodifiable view of the annotations for this field, empty if no annotations present or code gen param
+   * is not turned on
+   */
+  public Map<String, String> getFieldAnnotations() {
+    return Collections.unmodifiableMap(fieldAnnotations);
+  }
+
   public static void addStructMetaDataMap(Class<? extends TBase> sClass, Map<? extends TFieldIdEnum, FieldMetaData> map){
     structMap.put(sClass, map);
   }
diff --git a/lib/java/src/test/java/org/apache/thrift/TestAnnotationMetadata.java b/lib/java/src/test/java/org/apache/thrift/TestAnnotationMetadata.java
new file mode 100644
index 000000000..a9381e65d
--- /dev/null
+++ b/lib/java/src/test/java/org/apache/thrift/TestAnnotationMetadata.java
@@ -0,0 +1,61 @@
+/*
+ * 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.
+ */
+
+package org.apache.thrift;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.thrift.meta_data.FieldMetaData;
+import org.junit.Assert;
+import org.junit.Test;
+import thrift.test.OneOfEachBeans;
+import thrift.test.annotations.OneOfEachBeansWithAnnotations;
+
+public class TestAnnotationMetadata {
+
+    @Test
+    public void testWithoutParamShouldGenerateEmpty() {
+        Map<? extends TFieldIdEnum, FieldMetaData> structMetaDataMap = FieldMetaData.getStructMetaDataMap(OneOfEachBeans.class);
+        {
+            Map<String, String> metadata = structMetaDataMap.get(OneOfEachBeans._Fields.I16_LIST).getFieldAnnotations();
+            Assert.assertEquals(Collections.emptyMap(), metadata);
+        }
+        {
+            Map<String, String> metadata = structMetaDataMap.get(OneOfEachBeans._Fields.A_BITE).getFieldAnnotations();
+            Assert.assertEquals(Collections.emptyMap(), metadata);
+        }
+    }
+
+    @Test
+    public void testGeneratedAnnotations() {
+        Map<? extends TFieldIdEnum, FieldMetaData> structMetaDataMap = FieldMetaData.getStructMetaDataMap(OneOfEachBeansWithAnnotations.class);
+        {
+            Map<String, String> metadata = structMetaDataMap.get(OneOfEachBeansWithAnnotations._Fields.I16_LIST).getFieldAnnotations();
+            Assert.assertEquals(Collections.emptyMap(), metadata);
+        }
+        {
+            Map<String, String> metadata = structMetaDataMap.get(OneOfEachBeansWithAnnotations._Fields.A_BITE).getFieldAnnotations();
+            Map<String, String> expected = new HashMap<>();
+            expected.put("compression", "false");
+            Assert.assertEquals(expected, metadata);
+        }
+    }
+}
diff --git a/lib/java/src/test/resources/JavaAnnotationTest.thrift b/lib/java/src/test/resources/JavaAnnotationTest.thrift
new file mode 100644
index 000000000..925a05d16
--- /dev/null
+++ b/lib/java/src/test/resources/JavaAnnotationTest.thrift
@@ -0,0 +1,34 @@
+/*
+ * 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.
+ */
+
+namespace java thrift.test.annotations
+
+struct OneOfEachBeansWithAnnotations {
+  1: bool boolean_field,
+  2: byte a_bite (compression = "false"),
+  3: i16 integer16 (must_be_postive = "true"),
+  4: i32 integer32,
+  5: i64 integer64,
+  6: double double_precision (nan_inf_allowed = "false"),
+  7: string some_characters,
+  8: binary base64,
+  9: list<byte> byte_list (non_empty = "true"),
+  10: list<i16> i16_list,
+  11: list<i64> i64_list
+}