software.amazon.awssdk.enhanced.dynamodb.internal.converter.attribute.MapAttributeConverter Maven / Gradle / Ivy
/*
* 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 java.util.LinkedHashMap;
import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.function.Supplier;
import software.amazon.awssdk.annotations.Immutable;
import software.amazon.awssdk.annotations.SdkInternalApi;
import software.amazon.awssdk.annotations.ThreadSafe;
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.converter.StringConverter;
import software.amazon.awssdk.enhanced.dynamodb.internal.converter.TypeConvertingVisitor;
import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
/**
* A converter between a specific {@link Map} type and {@link AttributeValue}.
*
*
* This stores values in DynamoDB as a map from string to attribute value. This uses a configured {@link StringAttributeConverter}
* to convert the map keys to a string, and a configured {@link AttributeConverter} to convert the map values to an attribute
* value.
*
*
* This supports reading maps from DynamoDB. This uses a configured {@link StringAttributeConverter} to convert the map keys, and
* a configured {@link AttributeConverter} to convert the map values.
*
*
* A builder is exposed to allow defining how the map, key and value types are created and converted:
*
* AttributeConverter> mapConverter =
* MapAttributeConverter.builder(EnhancedType.mapOf(Integer.class, String.class))
* .mapConstructor(HashMap::new)
* .keyConverter(MonthDayStringConverter.create())
* .valueConverter(StringAttributeConverter.create())
* .build();
*
*
*
* For frequently-used types, static methods are exposed to reduce the amount of boilerplate involved in creation:
*
* AttributeConverter> mapConverter =
* MapAttributeConverter.mapConverter(MonthDayStringConverter.create(),
* StringAttributeConverter.create());
*
* AttributeConverter> sortedMapConverter =
* MapAttributeConverter.sortedMapConverter(MonthDayStringConverter.create(),
* StringAttributeConverter.create());
*
*
* @see MapAttributeConverter
*/
@SdkInternalApi
@ThreadSafe
@Immutable
public class MapAttributeConverter> implements AttributeConverter {
private final Delegate delegate;
private MapAttributeConverter(Delegate delegate) {
this.delegate = delegate;
}
public static MapAttributeConverter> mapConverter(StringConverter keyConverter,
AttributeConverter valueConverter) {
return builder(EnhancedType.mapOf(keyConverter.type(), valueConverter.type()))
.mapConstructor(LinkedHashMap::new)
.keyConverter(keyConverter)
.valueConverter(valueConverter)
.build();
}
public static MapAttributeConverter> concurrentMapConverter(StringConverter keyConverter,
AttributeConverter valueConverter) {
return builder(EnhancedType.concurrentMapOf(keyConverter.type(), valueConverter.type()))
.mapConstructor(ConcurrentHashMap::new)
.keyConverter(keyConverter)
.valueConverter(valueConverter)
.build();
}
public static MapAttributeConverter> sortedMapConverter(StringConverter keyConverter,
AttributeConverter valueConverter) {
return builder(EnhancedType.sortedMapOf(keyConverter.type(), valueConverter.type()))
.mapConstructor(TreeMap::new)
.keyConverter(keyConverter)
.valueConverter(valueConverter)
.build();
}
public static MapAttributeConverter> navigableMapConverter(StringConverter keyConverter,
AttributeConverter valueConverter) {
return builder(EnhancedType.navigableMapOf(keyConverter.type(), valueConverter.type()))
.mapConstructor(TreeMap::new)
.keyConverter(keyConverter)
.valueConverter(valueConverter)
.build();
}
public static , K, V> Builder builder(EnhancedType mapType) {
return new Builder<>(mapType);
}
@Override
public EnhancedType type() {
return delegate.type();
}
@Override
public AttributeValueType attributeValueType() {
return AttributeValueType.M;
}
@Override
public AttributeValue transformFrom(T input) {
return delegate.toAttributeValue(input).toAttributeValue();
}
@Override
public T transformTo(AttributeValue input) {
return delegate.fromAttributeValue(input);
}
private static final class Delegate, K, V> {
private final EnhancedType type;
private final Supplier mapConstructor;
private final StringConverter keyConverter;
private final AttributeConverter valueConverter;
private Delegate(Builder builder) {
this.type = builder.mapType;
this.mapConstructor = builder.mapConstructor;
this.keyConverter = builder.keyConverter;
this.valueConverter = builder.valueConverter;
}
public EnhancedType type() {
return type;
}
public EnhancedAttributeValue toAttributeValue(T input) {
Map result = new LinkedHashMap<>();
input.forEach((k, v) -> result.put(keyConverter.toString(k), valueConverter.transformFrom(v)));
return EnhancedAttributeValue.fromMap(result);
}
public T fromAttributeValue(AttributeValue input) {
return EnhancedAttributeValue.fromAttributeValue(input)
.convert(new TypeConvertingVisitor(Map.class, MapAttributeConverter.class) {
@Override
public T convertMap(Map value) {
T result = mapConstructor.get();
value.forEach((k, v) ->
result.put(keyConverter.fromString(k),
valueConverter.transformTo(v)));
return result;
}
});
}
}
public static final class Builder, K, V> {
private final EnhancedType mapType;
private StringConverter keyConverter;
private AttributeConverter valueConverter;
private Supplier mapConstructor;
private Builder(EnhancedType mapType) {
this.mapType = mapType;
}
public Builder mapConstructor(Supplier mapConstructor) {
this.mapConstructor = (Supplier) mapConstructor;
return this;
}
public Builder keyConverter(StringConverter keyConverter) {
this.keyConverter = keyConverter;
return this;
}
public Builder valueConverter(AttributeConverter valueConverter) {
this.valueConverter = valueConverter;
return this;
}
public MapAttributeConverter build() {
return new MapAttributeConverter<>(new Delegate<>(this));
}
}
}