1 /*
2  * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License").
5  * You may not use this file except in compliance with the License.
6  * A copy of the License is located at
7  *
8  *  http://aws.amazon.com/apache2.0
9  *
10  * or in the "license" file accompanying this file. This file is distributed
11  * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
12  * express or implied. See the License for the specific language governing
13  * permissions and limitations under the License.
14  */
15 
16 package software.amazon.awssdk.enhanced.dynamodb.internal.converter;
17 
18 import java.util.List;
19 import software.amazon.awssdk.annotations.SdkInternalApi;
20 import software.amazon.awssdk.enhanced.dynamodb.AttributeConverterProvider;
21 import software.amazon.awssdk.enhanced.dynamodb.DefaultAttributeConverterProvider;
22 
23 /**
24  * Static module to assist with the initialization of attribute converter providers for a StaticTableSchema.
25  */
26 @SdkInternalApi
27 public final class ConverterProviderResolver {
28 
29     private static final AttributeConverterProvider DEFAULT_ATTRIBUTE_CONVERTER =
30         DefaultAttributeConverterProvider.create();
31 
ConverterProviderResolver()32     private ConverterProviderResolver() {
33     }
34 
35     /**
36      * Static provider for the default attribute converters that are bundled with the DynamoDB Enhanced Client.
37      * This provider will be used by default unless overridden in the static table schema builder or using bean
38      * annotations.
39      */
defaultConverterProvider()40     public static AttributeConverterProvider defaultConverterProvider() {
41         return DEFAULT_ATTRIBUTE_CONVERTER;
42     }
43 
44     /**
45      * Resolves a list of attribute converter providers into a single provider. If the list is a singleton,
46      * it will just return that provider, otherwise it will combine them into a
47      * {@link ChainConverterProvider} using the order provided in the list.
48      *
49      * @param providers A list of providers to be combined in strict order
50      * @return A single provider that combines all the supplied providers or null if no providers were supplied
51      */
resolveProviders(List<AttributeConverterProvider> providers)52     public static AttributeConverterProvider resolveProviders(List<AttributeConverterProvider> providers) {
53         if (providers == null || providers.isEmpty()) {
54             return null;
55         }
56 
57         if (providers.size() == 1) {
58             return providers.get(0);
59         }
60 
61         return ChainConverterProvider.create(providers);
62     }
63 }
64