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

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/*
 * Copyright 2011-2014 Amazon Technologies, Inc.
 *
 * 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 static com.amazonaws.util.Throwables.failure;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectWriter;

/**
 * Simple JSON marshaller that uses Jackson mapper. It has all the limitations
 * of that library, the documentation of which is available here:
 * http://docs.codehaus.org/display/JACKSON/Home
 */
public class JsonMarshaller implements DynamoDBMarshaller {

    private static final ObjectMapper mapper = new ObjectMapper();
    private static final ObjectWriter writer = mapper.writer();

    @Override
    public String marshall(T obj) {

        try {
            return writer.writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            throw failure(e,
                    "Unable to marshall the instance of " + obj.getClass()
                            + "into a string");
        }
    }

    @Override
    public T unmarshall(Class clazz, String json) {
        try {
            return mapper.readValue(json, clazz);
        } catch (Exception e) {
            throw failure(e, "Unable to unmarshall the string " + json
                    + "into " + clazz);
        }
    }
}