com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMarshalling Maven / Gradle / Ivy
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The AWS Java SDK for Amazon DynamoDB module holds the client classes that are used for communicating with Amazon DynamoDB Service
/*
* Copyright 2011-2018 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.
* You may obtain a copy of the License at:
*
* http://aws.amazon.com/apache2.0
*
* 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 com.amazonaws.services.dynamodbv2.datamodeling;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.Set;
/**
* Annotation to mark a property as using a custom marshaller. This is required
* when storing anything other than {@link String}s, {@link Number}s, and
* {@link Set}s of the same to DynamoDB. Any object that can be converted into a
* String representation and vice versa can be saved in this manner. This
* annotation can be applied to either the getter method or the class field for
* the specific property. If the annotation is applied directly to the class
* field, the corresponding getter and setter must be declared in the same
* class.
*
* @see DynamoDBMarshaller
* @see JsonMarshaller
*
* @deprecated Replaced by {@link DynamoDBTypeConverted}
*
* A {@link DynamoDBTypeConverted} with {@link String} as source would
* perform the same conversion. Please consider, if your marshaller is thread
* safe before replacing. In the new implementation, a single instance of
* {@link DynamoDBTypeConverted} is created per field/attribute. In the old,
* an new instance of the marshaller was created for each call to
* {@code marshall} and {@code unmarshall}. If your marshaller/converter is not
* thread safe, it is recomended to specify a converter which will instantiate
* a new marshaller per call.
*
*
* public class CustomConverter<T> implements DynamoDBTypeConverter<String,T> {
* @Override
* public final String convert(final T object) {
* return ...
* }
* @Override
* public final T unconvert(final String object) {
* return ...
* }
* }
*
*/
@Deprecated
@DynamoDB
@DynamoDBTypeConverted(converter=DynamoDBMarshalling.Converter.class)
@DynamoDBTyped(DynamoDBMapperFieldModel.DynamoDBAttributeType.S)
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.METHOD})
public @interface DynamoDBMarshalling {
/**
* The class of the Marshaller that converts this property to and from a
* String.
*/
Class> marshallerClass();
/**
* Marshalling type converter.
*/
static final class Converter implements DynamoDBTypeConverter {
private final Class> marshallerClass;
private final Class targetType;
public Converter(final Class targetType, final DynamoDBMarshalling annotation) {
this.marshallerClass = (Class>)annotation.marshallerClass();
this.targetType = targetType;
}
@Override
public final String convert(final T object) {
return marshaller().marshall(object);
}
@Override
public final T unconvert(final String object) {
return marshaller().unmarshall(targetType, object);
}
private DynamoDBMarshaller marshaller() {
try {
return marshallerClass.newInstance();
} catch (final Exception e) {
throw new DynamoDBMappingException("Unable to instantiate marshaller " + marshallerClass, e);
}
}
}
}