dataminer-invocation-model/src/main/java/org/gcube/data/analysis/dminvocation/DataMinerInvocationManager.java

/**
 *
 */
package org.gcube.data.analysis.dminvocation;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.xml.XMLConstants;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.SchemaOutputResolver;
import javax.xml.bind.Unmarshaller;
import javax.xml.transform.Result;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;

import org.eclipse.persistence.jaxb.MarshallerProperties;
import org.gcube.data.analysis.dminvocation.model.DataMinerInvocation;
import org.xml.sax.SAXException;


/**
 * The Class DataMinerInvocationManager.
 *
 * @author Francesco Mangiacrapa at ISTI-CNR (francesco.mangiacrapa@isti.cnr.it)
 * Dec 4, 2018
 */
public class DataMinerInvocationManager {

	/**
	 * Marshaling.
	 *
	 * @param dmInvocation the dm invocation
	 * @param mediaType the media type
	 * @return the byte array output stream
	 * @throws JAXBException the JAXB exception
	 * @throws SAXException
	 * @throws IOException
	 */
	public static ByteArrayOutputStream marshaling(DataMinerInvocation dmInvocation, MediaType mediaType) throws JAXBException, IOException, SAXException
	{
	    JAXBContext jaxbContext = JAXBContext.newInstance(DataMinerInvocation.class);
	    Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
	    jaxbMarshaller = generateAndSetSchema(jaxbMarshaller);

	    jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);

	    if(mediaType==null)
	    	mediaType = MediaType.ApplicationXML;

	    switch (mediaType) {
		case ApplicationJSON:
			jaxbMarshaller.setProperty(MarshallerProperties.JSON_INCLUDE_ROOT, Boolean.TRUE);
		case ApplicationXML:
		default:
			jaxbMarshaller.setProperty(MarshallerProperties.MEDIA_TYPE, mediaType.getMimeType());
		}

	    ByteArrayOutputStream baos = new ByteArrayOutputStream();
	    jaxbMarshaller.marshal(dmInvocation, baos);
	    return baos;
	}


	/**
	 * Unmarshaling.
	 *
	 * @param dmInvocationXMLStream the dm invocation xml file
	 * @param mediaType the media type
	 * @return the data miner invocation
	 * @throws JAXBException the JAXB exception
	 * @throws IOException Signals that an I/O exception has occurred.
	 * @throws SAXException the SAX exception
	 */
	public static DataMinerInvocation unmarshaling(InputStream dmInvocationXMLStream, MediaType mediaType) throws JAXBException, IOException, SAXException
	{
		//unMarshalingCategories();
	    JAXBContext jaxbContext = JAXBContext.newInstance(DataMinerInvocation.class);
	    Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();

	    jaxbUnmarshaller = generateAndSetSchema(jaxbUnmarshaller);

	    if(mediaType==null)
	    	mediaType = MediaType.ApplicationXML;

	    switch (mediaType) {
		case ApplicationJSON:
			jaxbUnmarshaller.setProperty(MarshallerProperties.JSON_INCLUDE_ROOT, Boolean.TRUE);
		case ApplicationXML:
		default:
			jaxbUnmarshaller.setProperty(MarshallerProperties.MEDIA_TYPE, mediaType.getMimeType());
		}

	    //We had written this file in marshalling example
	    return (DataMinerInvocation) jaxbUnmarshaller.unmarshal(dmInvocationXMLStream);

	}

	/**
	 * Generate and set schema.
	 *
	 * @param unmarshaller the unmarshaller
	 * @return the unmarshaller
	 * @throws JAXBException the JAXB exception
	 * @throws IOException Signals that an I/O exception has occurred.
	 * @throws SAXException the SAX exception
	 */
	private static Unmarshaller generateAndSetSchema(Unmarshaller unmarshaller) throws JAXBException, IOException, SAXException {

	    // generate schema
	    ByteArrayStreamOutputResolver schemaOutput = new ByteArrayStreamOutputResolver();
	    JAXBContext jaxbContext = JAXBContext.newInstance(DataMinerInvocation.class);
	    jaxbContext.generateSchema(schemaOutput);

	    // load schema
	    ByteArrayInputStream schemaInputStream = new ByteArrayInputStream(schemaOutput.getSchemaContent());
	    SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
	    Schema schema = sf.newSchema(new StreamSource(schemaInputStream));

	    // set schema on unmarshaller
	    unmarshaller.setSchema(schema);
	    return unmarshaller;
	}

	/**
	 * Generate and set schema.
	 *
	 * @param unmarshaller the unmarshaller
	 * @return the unmarshaller
	 * @throws JAXBException the JAXB exception
	 * @throws IOException Signals that an I/O exception has occurred.
	 * @throws SAXException the SAX exception
	 */
	private static Marshaller generateAndSetSchema(Marshaller marshaller) throws JAXBException, IOException, SAXException {

	    // generate schema
	    ByteArrayStreamOutputResolver schemaOutput = new ByteArrayStreamOutputResolver();
	    JAXBContext jaxbContext = JAXBContext.newInstance(DataMinerInvocation.class);
	    jaxbContext.generateSchema(schemaOutput);

	    // load schema
	    ByteArrayInputStream schemaInputStream = new ByteArrayInputStream(schemaOutput.getSchemaContent());
	    SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
	    Schema schema = sf.newSchema(new StreamSource(schemaInputStream));

	    // set schema on unmarshaller
	    marshaller.setSchema(schema);
	    return marshaller;
	}


	/**
	 * The Class ByteArrayStreamOutputResolver.
	 *
	 * @author Francesco Mangiacrapa at ISTI-CNR (francesco.mangiacrapa@isti.cnr.it)
	 * Dec 7, 2018
	 */
	private static class ByteArrayStreamOutputResolver extends SchemaOutputResolver {

	    private ByteArrayOutputStream schemaOutputStream;

	    /* (non-Javadoc)
    	 * @see javax.xml.bind.SchemaOutputResolver#createOutput(java.lang.String, java.lang.String)
    	 */
    	public Result createOutput(String namespaceURI, String suggestedFileName) throws IOException {

	        schemaOutputStream = new ByteArrayOutputStream();
	        StreamResult result = new StreamResult(schemaOutputStream);

	        // We generate single XSD, so generator will not use systemId property
	        // Nevertheless, it validates if it's not null.
	        result.setSystemId("");

	        return result;
	    }

	    /**
    	 * Gets the schema content.
    	 *
    	 * @return the schema content
    	 */
    	public byte[] getSchemaContent() {
	        return schemaOutputStream.toByteArray();
	    }
	}
}