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DavidSeptimusDavidSeptimus
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Adds polymorphic TableSchema implementation
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‎services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/mapper/PolymorphicTableSchema.java

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/*
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* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License").
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* You may not use this file except in compliance with the License.
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* A copy of the License is located at
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*
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* http://aws.amazon.com/apache2.0
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*
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* or in the "license" file accompanying this file. This file is distributed
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* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
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* express or implied. See the License for the specific language governing
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* permissions and limitations under the License.
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*/
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package software.amazon.awssdk.enhanced.dynamodb.mapper;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.function.Function;
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import java.util.stream.Collectors;
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import software.amazon.awssdk.annotations.SdkPublicApi;
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import software.amazon.awssdk.enhanced.dynamodb.EnhancedType;
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import software.amazon.awssdk.enhanced.dynamodb.TableMetadata;
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import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
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import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbSubtypes;
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import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.Subtype;
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import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
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@SdkPublicApi
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public class PolymorphicTableSchema<T> implements TableSchema<T> {
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private final Class<T> rootType;
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private final SubtypeInfo<T> subtypeInfo;
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private final Map<Class<? extends T>, TableSchema<T>> schemasBySubtype;
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private final TableSchema<T> rootSchema;
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static class SubtypeInfo<T> {
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String dynamoDbAttribute;
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List<Class<? extends T>> subtypes = new ArrayList<>();
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Map<String, Class<T>> subTypesByAttributeValue = new HashMap<>();
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Map<Class<? extends T>, String> attributeValuesBySubtype = new HashMap<>();
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}
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protected PolymorphicTableSchema(Class<T> rootType, Function<Class<? extends T>, TableSchema<T>> schemaGenerator) {
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this.rootType = rootType;
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subtypeInfo = resolveInfo(rootType);
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rootSchema = schemaGenerator.apply(rootType);
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schemasBySubtype = subtypeInfo.subtypes.stream().collect(Collectors.toMap(t -> t, schemaGenerator::apply));
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}
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public static <T> PolymorphicTableSchema<T> createImmutable(Class<T> immutableClass) {
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return new PolymorphicTableSchema<>(immutableClass, (t) -> (TableSchema<T>) ImmutableTableSchema.create(t));
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}
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public static <T> PolymorphicTableSchema<T> createBean(Class<T> beanClass) {
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return new PolymorphicTableSchema<>(beanClass, (t) -> (TableSchema<T>) BeanTableSchema.create(t));
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}
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private static <T> SubtypeInfo<T> resolveInfo(Class<T> rootType) {
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SubtypeInfo<T> subtypeInfo = new SubtypeInfo();
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if (!rootType.isAnnotationPresent(DynamoDbSubtypes.class)) {
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return subtypeInfo;
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}
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DynamoDbSubtypes subtypesAnnotation = rootType.getAnnotation(DynamoDbSubtypes.class);
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subtypeInfo.dynamoDbAttribute = subtypesAnnotation.dynamoDbAttribute();
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subtypeInfo.subTypesByAttributeValue = Arrays
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.stream(subtypesAnnotation.subtypes())
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.filter(s -> isSubtypeOf(s.subType(), rootType))
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.collect(Collectors.toMap(Subtype::attributeValue, s -> (Class<T>) s.subType()));
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subtypeInfo.attributeValuesBySubtype = subtypeInfo.subTypesByAttributeValue
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.entrySet()
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.stream()
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.collect(Collectors.toMap(e -> e.getValue(), e -> e.getKey()));
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subtypeInfo.subtypes = new ArrayList<>(subtypeInfo.subTypesByAttributeValue.values());
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return subtypeInfo;
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}
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private static boolean isSubtypeOf(Class<?> subclass, Class<?> superclass) {
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Class<?> currentType;
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do {
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currentType = subclass.getSuperclass();
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} while (currentType != null && currentType != superclass);
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return currentType == superclass;
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}
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private TableSchema<T> resolveTableSchema(String subtypeAttributeValue) {
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Class<T> resolvedType = subtypeInfo.subTypesByAttributeValue.getOrDefault(subtypeAttributeValue, rootType);
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return schemasBySubtype.getOrDefault(resolvedType, rootSchema);
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}
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private TableSchema<T> resolveTableSchema(Class<T> itemType) {
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return this.schemasBySubtype.getOrDefault(itemType, rootSchema);
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}
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private String resolveTypeAttributeValue(Class<?> itemType) {
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return this.subtypeInfo.attributeValuesBySubtype.get(itemType);
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}
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private Map<String, AttributeValue> withTypeInformation(T item, Map<String, AttributeValue> attributes) {
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Map<String, AttributeValue> modifiedAttributes = new HashMap<>(attributes);
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String subtypeAttributeValue = resolveTypeAttributeValue(item.getClass());
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if (subtypeAttributeValue != null) {
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modifiedAttributes.put(subtypeInfo.dynamoDbAttribute, AttributeValue.builder().s(subtypeAttributeValue).build());
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}
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return Collections.unmodifiableMap(modifiedAttributes);
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}
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@Override
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public T mapToItem(Map<String, AttributeValue> attributeMap) {
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String typeAttributeValue = attributeMap.get(subtypeInfo.dynamoDbAttribute).s();
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TableSchema<? extends T> resolvedSchema = typeAttributeValue == null
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? rootSchema
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: resolveTableSchema(typeAttributeValue);
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return resolvedSchema.mapToItem(attributeMap);
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}
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@Override
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public Map<String, AttributeValue> itemToMap(T item, boolean ignoreNulls) {
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TableSchema<T> resolvedSchema = resolveTableSchema((Class<T>) item.getClass());
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Map<String, AttributeValue> mappedItem = resolvedSchema.itemToMap(item, ignoreNulls);
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return withTypeInformation(item, mappedItem);
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}
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@Override
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public Map<String, AttributeValue> itemToMap(T item, Collection<String> attributes) {
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TableSchema<T> resolvedSchema = resolveTableSchema((Class<T>) item.getClass());
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Map<String, AttributeValue> mappedItem = resolvedSchema.itemToMap(item, attributes);
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return withTypeInformation(item, mappedItem);
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}
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@Override
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public AttributeValue attributeValue(T item, String attributeName) {
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TableSchema<T> resolvedSchema = resolveTableSchema((Class<T>) item.getClass());
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return resolvedSchema.attributeValue(item, attributeName);
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}
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@Override
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public TableMetadata tableMetadata() {
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return rootSchema.tableMetadata();
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}
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@Override
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public EnhancedType<T> itemType() {
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return rootSchema.itemType();
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}
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@Override
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public List<String> attributeNames() {
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return rootSchema.attributeNames();
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}
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@Override
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public boolean isAbstract() {
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return schemasBySubtype.values().stream().allMatch(TableSchema::isAbstract);
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}
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}

‎services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/mapper/annotations/DynamoDbSubtypes.java

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/*
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* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License").
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* You may not use this file except in compliance with the License.
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* A copy of the License is located at
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*
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* http://aws.amazon.com/apache2.0
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*
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* or in the "license" file accompanying this file. This file is distributed
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* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
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* express or implied. See the License for the specific language governing
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* permissions and limitations under the License.
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*/
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package software.amazon.awssdk.enhanced.dynamodb.mapper.annotations;
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import java.lang.annotation.ElementType;
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import java.lang.annotation.Retention;
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import java.lang.annotation.RetentionPolicy;
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import java.lang.annotation.Target;
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import software.amazon.awssdk.annotations.SdkPublicApi;
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import software.amazon.awssdk.enhanced.dynamodb.internal.mapper.BeanTableSchemaAttributeTags;
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@SdkPublicApi
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@Target({ElementType.TYPE})
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@Retention(RetentionPolicy.RUNTIME)
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@BeanTableSchemaAttributeTag(BeanTableSchemaAttributeTags.class)
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public @interface DynamoDbSubtypes {
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String dynamoDbAttribute();
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Subtype[] subtypes();
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}

‎services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/mapper/annotations/Subtype.java

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/*
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* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License").
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* You may not use this file except in compliance with the License.
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* A copy of the License is located at
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*
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* http://aws.amazon.com/apache2.0
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*
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* or in the "license" file accompanying this file. This file is distributed
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* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
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* express or implied. See the License for the specific language governing
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* permissions and limitations under the License.
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*/
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package software.amazon.awssdk.enhanced.dynamodb.mapper.annotations;
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import java.lang.annotation.ElementType;
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import java.lang.annotation.Retention;
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import java.lang.annotation.RetentionPolicy;
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import java.lang.annotation.Target;
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import software.amazon.awssdk.annotations.SdkPublicApi;
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import software.amazon.awssdk.enhanced.dynamodb.internal.mapper.BeanTableSchemaAttributeTags;
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@SdkPublicApi
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@Target({ElementType.ANNOTATION_TYPE})
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@Retention(RetentionPolicy.RUNTIME)
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@BeanTableSchemaAttributeTag(BeanTableSchemaAttributeTags.class)
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public @interface Subtype {
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String attributeValue();
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Class<?> subType();
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}

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