com.amazonaws.services.dynamodbv2.datamodeling.ItemConverter Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of aws-java-sdk-osgi Show documentation

The AWS SDK for Java with support for OSGi. The AWS SDK for Java provides Java APIs for building software on AWS' cost-effective, scalable, and reliable infrastructure products. The AWS Java SDK allows developers to code against APIs for all of Amazon's infrastructure web services (Amazon S3, Amazon EC2, Amazon SQS, Amazon Relational Database Service, Amazon AutoScaling, etc).

There is a newer version: 1.11.60

Show newest version

/*
 * Copyright 2014-2016 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.reflect.Method;
import java.util.Map;

import com.amazonaws.services.dynamodbv2.model.AttributeValue;

/**
 * The concrete realization of a strategy for converting between Java objects
 * and DynamoDB AttributeValues. Typically created by a
 * {@link ConversionSchema}.
 */
public interface ItemConverter {
    /**
     * Returns the metadata (e.g. name, type) of the DynamoDB attribute that the
     * return value of the given getter will be converted to.
     *
     * @param getter the getter method to inspect
     * @return the metadata of the DynamoDB attribute that the result of the
     *         getter will be converted to
     */
    DynamoDBMapperFieldModel getFieldModel(Method getter);

    /**
     * Converts a Java object into a DynamoDB AttributeValue. Potentially able
     * to handle both scalar and complex types.
     *
     * @param getter the getter that returned the value to be converted
     * @param value the value to be converted
     * @return the converted AttributeValue
     */
    AttributeValue convert(Method getter, Object value);

    /**
     * Converts an appropriately-annotated POJO into a Map of AttributeValues.
     *
     * @param value the POJO to convert
     * @return the resulting map of attribute values
     */
    Map convert(Object value);

    /**
     * Reverses the {@link #convert(Method, Object)} method, turning a
     * DynamoDB AttributeValue back into a Java object suitable for passing
     * to the given setter.
     *
     * @param getter the getter for the value to be unconverted
     * @param setter the setter for the value to be unconverted
     * @param value the attribute value to be unconverted
     * @return the unconverted Java object
     */
    Object unconvert(Method getter, Method setter, AttributeValue value);

    /**
     * Reverses the {@link #convert(Object)} method, turning a map of attribute
     * values back into a POJO of the given class.
     *
     * @param  the compile-time type of the object to create
     * @param clazz the runtime type of the object to create
     * @param values the the map of attribute values to unconvert
     * @return the unconverted POJO
     */
     T unconvert(Class clazz, Map values);
}