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petals-bc-rest Binding Component description
There is a newer version: 2.4.0
/**
 * Copyright (c) 2007-2012 EBM WebSourcing, 2012-2020 Linagora
 * 
 * This program/library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 2.1 of the License, or (at your
 * option) any later version.
 * 
 * This program/library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
 * for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program/library; If not, see http://www.gnu.org/licenses/
 * for the GNU Lesser General Public License version 2.1.
 */
package org.ow2.petals.binding.rest.exchange;

import java.io.InputStream;
import java.io.OutputStream;

import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.stax.StAXResult;
import javax.xml.transform.stax.StAXSource;

import com.ebmwebsourcing.easycommons.lang.reflect.ReflectionHelper;
import com.ebmwebsourcing.easycommons.xml.Transformers;

import de.odysseus.staxon.base.AbstractXMLStreamReader;

public final class JSONHelper {

    private JSONHelper() {
        // Utility class --> No constructor
    }

    /**
     * Convert the given JSON {@link InputStream} into XML contained in the resulting stream
     * 
     * @param input
     *            the JSON to convert
     * @param output
     *            the resulting output in which the JSON converted into XML will be written
     * @param inputFactory
     *            the JSON to XML convertion configuration
     * @throws XMLStreamException
     *             if a XML unexpected processing error occurs (XML well-formedness errors as well as unexpected
     *             processing conditions)
     * @throws TransformerException
     *             if an unrecoverable error occurs during the course of the transformation
     */
    public static void convertJSONToXML(final InputStream input, final Result output,
            final XMLInputFactory inputFactory) throws XMLStreamException, TransformerException {
        final Transformer transformer = Transformers.takeTransformer();
        try {
            transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");

            transformer.transform(getSourceFromJSON(input, inputFactory), output);
        } finally {
            Transformers.releaseTransformer(transformer);
        }
    }

    public static Source getSourceFromJSON(final InputStream input, final XMLInputFactory inputFactory)
            throws XMLStreamException {
        XMLStreamReader reader = inputFactory.createXMLStreamReader(input);
        // because of https://bugs.openjdk.java.net/browse/JDK-8016914, we need to set the version
        // TODO when https://github.com/beckchr/staxon/issues/39 is resolved, we can use it instead of reflection
        if (reader instanceof AbstractXMLStreamReader) {
            ReflectionHelper.setFieldValue(AbstractXMLStreamReader.class, reader, "version", "1.0", false);
        }
        return new StAXSource(reader);
    }

    /**
     * Convert XML from the specified source to the specified output stream.
     * 
     * @param source
     *            a XML source
     * @param output
     *            an output stream for the converted JSON
     * @param outputFactory
     *            the XML/JSON mapping convention
     * @throws TransformerException
     *             if an unrecoverable error occurs during the course of the transformation
     * @throws XMLStreamException
     * 
     */
    public static final void convertXMLToJSON(final Source source, final OutputStream output,
            final XMLOutputFactory outputFactory) throws TransformerException, XMLStreamException {

        final Transformer transformer = Transformers.takeTransformer();
        try {
            transformer.transform(source, new StAXResult(outputFactory.createXMLStreamWriter(output)));
        } finally {
            Transformers.releaseTransformer(transformer);
        }
    }
}