software.amazon.awssdk.enhanced.dynamodb.internal.converter.attribute.StringAttributeConverter Maven / Gradle / Ivy

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/*
 * 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.internal.converter.attribute;

import static java.util.stream.Collectors.toList;

import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.function.BinaryOperator;
import java.util.stream.Collectors;
import software.amazon.awssdk.annotations.Immutable;
import software.amazon.awssdk.annotations.SdkInternalApi;
import software.amazon.awssdk.annotations.ThreadSafe;
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.enhanced.dynamodb.AttributeConverter;
import software.amazon.awssdk.enhanced.dynamodb.AttributeValueType;
import software.amazon.awssdk.enhanced.dynamodb.EnhancedType;
import software.amazon.awssdk.enhanced.dynamodb.internal.AttributeValues;
import software.amazon.awssdk.enhanced.dynamodb.internal.converter.TypeConvertingVisitor;
import software.amazon.awssdk.enhanced.dynamodb.internal.converter.string.BooleanStringConverter;
import software.amazon.awssdk.enhanced.dynamodb.internal.converter.string.ByteArrayStringConverter;
import software.amazon.awssdk.services.dynamodb.model.AttributeValue;

/**
 * A converter between {@link String} and {@link AttributeValue}.
 *
 * 
 * This stores values in DynamoDB as a string.
 *
 * 

 * This supports reading any DynamoDB attribute type into a string type, so it is very useful for logging information stored in
 * DynamoDB.
 */
@SdkInternalApi
@ThreadSafe
@Immutable
public final class StringAttributeConverter implements AttributeConverter {
    public static StringAttributeConverter create() {
        return new StringAttributeConverter();
    }

    @Override
    public EnhancedType type() {
        return EnhancedType.of(String.class);
    }

    @Override
    public AttributeValueType attributeValueType() {
        return AttributeValueType.S;
    }

    @Override
    public AttributeValue transformFrom(String input) {
        return input == null ? AttributeValues.nullAttributeValue() : AttributeValue.builder().s(input).build();
    }

    @Override
    public String transformTo(AttributeValue input) {
        return Visitor.toString(input);
    }

    private static final class Visitor extends TypeConvertingVisitor {
        private static final Visitor INSTANCE = new Visitor();

        private Visitor() {
            super(String.class, StringAttributeConverter.class);
        }

        @Override
        public String convertString(String value) {
            return value;
        }

        @Override
        public String convertNumber(String value) {
            return value;
        }

        @Override
        public String convertBytes(SdkBytes value) {
            return ByteArrayStringConverter.create().toString(value.asByteArray());
        }

        @Override
        public String convertBoolean(Boolean value) {
            return BooleanStringConverter.create().toString(value);
        }

        @Override
        public String convertSetOfStrings(List value) {
            return value.toString();
        }

        @Override
        public String convertSetOfNumbers(List value) {
            return value.toString();
        }

        @Override
        public String convertSetOfBytes(List value) {
            return value.stream()
                        .map(this::convertBytes)
                        .collect(Collectors.joining(",", "[", "]"));
        }

        @Override
        public String convertMap(Map value) {
            BinaryOperator