UUIDSetToStringSetMarshaller.java

/*
 * Copyright 2014-2017 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.marshallers;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.UUID;

import com.amazonaws.services.dynamodbv2.datamodeling.ArgumentMarshaller.StringSetAttributeMarshaller;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;

/**
 * A marshaller that marshals sets of Java {@code Object} objects into
 * DynamoDB StringSets.
 *
 * @author Sergei Egorov
 */
public class UUIDSetToStringSetMarshaller
        implements StringSetAttributeMarshaller {

    private static final UUIDSetToStringSetMarshaller INSTANCE =
            new UUIDSetToStringSetMarshaller();

    public static UUIDSetToStringSetMarshaller instance() {
        return INSTANCE;
    }

    private UUIDSetToStringSetMarshaller() {
    }

    @Override
    public AttributeValue marshall(Object obj) {
        @SuppressWarnings("unchecked")
        Set<UUID> uuids = (Set<UUID>) obj;

        List<String> strings = new ArrayList<String>(uuids.size());
        for (UUID uuid : uuids) {
            strings.add(uuid.toString());
        }

        return new AttributeValue().withSS(strings);
    }
}