org.eclipse.om2m.datamapping.jaxb.Mapper.java Source code

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Here is the source code for org.eclipse.om2m.datamapping.jaxb.Mapper.java

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/*******************************************************************************
 * Copyright (c) 2013-2016 LAAS-CNRS (www.laas.fr)
 * 7 Colonel Roche 31077 Toulouse - France
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Initial Contributors:
 *     Thierry Monteil : Project manager, technical co-manager
 *     Mahdi Ben Alaya : Technical co-manager
 *     Samir Medjiah : Technical co-manager
 *     Khalil Drira : Strategy expert
 *     Guillaume Garzone : Developer
 *     Franois Assaoui : Developer
 *
 * New contributors :
 *******************************************************************************/
package org.eclipse.om2m.datamapping.jaxb;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.StringReader;
import java.util.HashMap;
import java.util.Map;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.eclipse.om2m.commons.constants.MimeMediaType;
import org.eclipse.om2m.datamapping.service.DataMapperService;
import org.eclipse.persistence.jaxb.JAXBContextProperties;
import org.eclipse.persistence.jaxb.MarshallerProperties;
import org.eclipse.persistence.jaxb.UnmarshallerProperties;

/**
 * Datamapper (JAXB) implementing DataMapper service
 */
public class Mapper implements DataMapperService {

    /** XML Mapper logger */
    private static Log LOGGER = LogFactory.getLog(Mapper.class);
    /** JAXB Context, entry point to the JAXB API */
    private JAXBContext context;
    /** Resource package name used for JAXBContext instantiation */
    private String resourcePackage = "org.eclipse.om2m.commons.resource";
    private String mediaType;

    /**
     * Private constructor that will create the JAXB context.
     */
    public Mapper(String mediaType) {
        this.mediaType = mediaType;
        try {
            if (context == null) {
                if (mediaType.equals(MimeMediaType.JSON)) {
                    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
                    InputStream iStream = classLoader.getResourceAsStream("json-binding.xml");
                    Map<String, Object> properties = new HashMap<String, Object>();
                    properties.put(JAXBContextProperties.OXM_METADATA_SOURCE, iStream);
                    context = JAXBContext.newInstance(resourcePackage, classLoader, properties);
                } else {
                    context = JAXBContext.newInstance(resourcePackage);
                }
            }
        } catch (JAXBException e) {
            LOGGER.error("Create JAXBContext error", e);
        }
    }

    /**
     * Converts a resource Java object into resource XML representation.
     * 
     * @param object
     *            - resource Java object
     * @return resource XML representation
     */
    @Override
    public String objToString(Object obj) {
        try {
            Marshaller marshaller = context.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            OutputStream outputStream = new ByteArrayOutputStream();
            marshaller.setProperty(MarshallerProperties.MEDIA_TYPE, mediaType);
            marshaller.setProperty(MarshallerProperties.JSON_INCLUDE_ROOT, true);
            marshaller.marshal(obj, outputStream);
            return outputStream.toString();
        } catch (JAXBException e) {
            LOGGER.error("JAXB marshalling error!", e);
        }
        return null;
    }

    /**
     * Converts a resource XML representation data into resource Java object.
     * 
     * @param representation
     *            - resource XML representation
     * @return resource Java object
     */
    @Override
    public Object stringToObj(String representation) {
        if (representation.isEmpty()) {
            return null;
        }
        StringReader stringReader = new StringReader(representation);
        try {
            Unmarshaller unmarshaller = context.createUnmarshaller();
            unmarshaller.setProperty(UnmarshallerProperties.MEDIA_TYPE, mediaType);
            unmarshaller.setProperty(UnmarshallerProperties.JSON_INCLUDE_ROOT, true);

            return unmarshaller.unmarshal(stringReader);
        } catch (JAXBException e) {
            LOGGER.error("JAXB unmarshalling error!", e);
        }
        return null;
    }

    @Override
    public String getServiceDataType() {
        return mediaType;
    }

}