ddb-enhanced: Annotated immutable class introspector now ignores 'toBuilder' method allowing easier integration with libraries that auto-generate this method on immutable data classes. (aws#2735)

Author: bmaizels

.changes/next-release/feature-DynamoDBEnhancedClient-baf78b8.json

@@ -0,0 +1,6 @@
+{
+    "category": "DynamoDB Enhanced Client", 
+    "contributor": "bmaizels", 
+    "type": "feature", 
+    "description": "Annotated immutable class introspector now ignores 'toBuilder' method allowing easier integration with libraries that auto-generate this method on immutable data classes."
+}

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/immutable/ImmutableIntrospector.java

@@ -24,6 +24,7 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 import software.amazon.awssdk.annotations.SdkInternalApi;
 import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbIgnore;
 import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbImmutable;
@@ -32,20 +33,23 @@
 public class ImmutableIntrospector {
     private static final String BUILD_METHOD = "build";
     private static final String BUILDER_METHOD = "builder";
+    private static final String TO_BUILDER_METHOD = "toBuilder";
     private static final String GET_PREFIX = "get";
     private static final String IS_PREFIX = "is";
     private static final String SET_PREFIX = "set";
 
+    private static final String[] METHODS_TO_IGNORE = { TO_BUILDER_METHOD };
+
     private static volatile ImmutableIntrospector INSTANCE = null;
 
     // Methods from Object are commonly overridden and confuse the mapper, automatically exclude any method with a name
     // that matches a method defined on Object.
     private final Set<String> namesToExclude;
 
     private ImmutableIntrospector() {
-        this.namesToExclude = Collections.unmodifiableSet(Arrays.stream(Object.class.getMethods())
-                                                                .map(Method::getName)
-                                                                .collect(Collectors.toSet()));
+        this.namesToExclude = Collections.unmodifiableSet(
+            Stream.concat(Arrays.stream(Object.class.getMethods()).map(Method::getName), Arrays.stream(METHODS_TO_IGNORE))
+                  .collect(Collectors.toSet()));
     }
 
     public static <T> ImmutableInfo<T> getImmutableInfo(Class<T> immutableClass) {

services-custom/dynamodb-enhanced/src/test/java/software/amazon/awssdk/enhanced/dynamodb/mapper/ImmutableTableSchemaTest.java

@@ -33,6 +33,7 @@
 import software.amazon.awssdk.enhanced.dynamodb.mapper.testbeans.FlattenedImmutableImmutable;
 import software.amazon.awssdk.enhanced.dynamodb.mapper.testbeans.NestedImmutable;
 import software.amazon.awssdk.enhanced.dynamodb.mapper.testbeans.NestedImmutableIgnoreNulls;
+import software.amazon.awssdk.enhanced.dynamodb.mapper.testbeans.ToBuilderImmutable;
 import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
 
 public class ImmutableTableSchemaTest {
@@ -281,4 +282,20 @@ public void dynamoDbIgnoreNulls_shouldOmitNulls() {
         assertThat(itemMap, hasEntry("innerBean1", expectedMapForInnerBean1));
         assertThat(itemMap.get("innerBean2").m(), hasEntry("attribute2", nullAttributeValue()));
     }
+
+    @Test
+    public void toBuilderImmutable_ignoresToBuilderMethod() {
+        ImmutableTableSchema<ToBuilderImmutable> toBuilderImmutableTableSchema =
+            ImmutableTableSchema.create(ToBuilderImmutable.class);
+
+        ToBuilderImmutable toBuilderImmutable = ToBuilderImmutable.builder()
+                                                                  .id("id-value")
+                                                                  .attribute1("one")
+                                                                  .build();
+
+        Map<String, AttributeValue> itemMap = toBuilderImmutableTableSchema.itemToMap(toBuilderImmutable, true);
+        assertThat(itemMap.size(), is(2));
+        assertThat(itemMap, hasEntry("id", stringValue("id-value")));
+        assertThat(itemMap, hasEntry("attribute1", stringValue("one")));
+    }
 }

services-custom/dynamodb-enhanced/src/test/java/software/amazon/awssdk/enhanced/dynamodb/mapper/testbeans/ToBuilderImmutable.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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 software.amazon.awssdk.enhanced.dynamodb.mapper.testbeans;
+
+import java.util.List;
+import java.util.Map;
+import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbImmutable;
+import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbPartitionKey;
+
+@DynamoDbImmutable(builder = ToBuilderImmutable.Builder.class)
+public class ToBuilderImmutable {
+    private final String id;
+    private final String attribute1;
+
+    private ToBuilderImmutable(Builder b) {
+        this.id = b.id;
+        this.attribute1 = b.attribute1;
+    }
+
+    @DynamoDbPartitionKey
+    public String id() {
+        return this.id;
+    }
+
+    public String attribute1() {
+        return attribute1;
+    }
+
+    public Builder toBuilder() {
+        return builder().id(this.id).attribute1(this.attribute1);
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public static final class Builder {
+        private String id;
+        private String attribute1;
+
+        public Builder id(String id) {
+            this.id = id;
+            return this;
+        }
+
+        public Builder attribute1(String attribute1) {
+            this.attribute1 = attribute1;
+            return this;
+        }
+
+        public ToBuilderImmutable build() {
+            return new ToBuilderImmutable(this);
+        }
+    }
+}