JAXBElementXmlProvider.java

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 * to you under the Apache License, Version 2.0 (the
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package org.apache.wink.common.internal.providers.entity.xml;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.nio.charset.Charset;

import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;

import org.apache.wink.common.internal.i18n.Messages;
import org.apache.wink.common.internal.utils.MediaTypeUtils;
import org.apache.wink.common.utils.ProviderUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Provider
@Consumes( {MediaType.TEXT_XML, MediaType.APPLICATION_XML, MediaType.WILDCARD})
@Produces( {MediaType.TEXT_XML, MediaType.APPLICATION_XML, MediaType.WILDCARD})
public class JAXBElementXmlProvider extends AbstractJAXBProvider implements
    MessageBodyReader<JAXBElement<?>>, MessageBodyWriter<JAXBElement<?>> {

    private static final Logger logger = LoggerFactory.getLogger(JAXBElementXmlProvider.class);

    public boolean isReadable(Class<?> type,
                              Type genericType,
                              Annotation[] annotations,
                              MediaType mediaType) {
        return isJAXBElement(type, genericType) && isSupportedMediaType(mediaType);
    }

    public JAXBElement<?> readFrom(Class<JAXBElement<?>> type,
                                   Type genericType,
                                   Annotation[] annotations,
                                   MediaType mediaType,
                                   MultivaluedMap<String, String> httpHeaders,
                                   InputStream entityStream) throws IOException,
        WebApplicationException {
        ParameterizedType parameterizedType = (ParameterizedType)genericType;
        Class<?> classToFill = (Class<?>)parameterizedType.getActualTypeArguments()[0];
        JAXBElement<?> unmarshaledResource = null;
        Unmarshaller unmarshaller = null;

        XMLStreamReader xmlStreamReader = null;
        try {
            JAXBContext context = getContext(classToFill, mediaType);
            unmarshaller = getJAXBUnmarshaller(type, context, mediaType);
            String charset = ProviderUtils.getCharsetOrNull(mediaType);
            if (charset == null) {
                // use default
                // performance is better, though the charset cannot be ensured
                xmlStreamReader = getXMLStreamReader(entityStream);
                unmarshaledResource = unmarshaller.unmarshal(xmlStreamReader, classToFill);
                closeXMLStreamReader(xmlStreamReader);
            } else {
                xmlStreamReader = getXMLStreamReader(new InputStreamReader(entityStream, Charset.forName(charset)));
                unmarshaledResource = unmarshaller.unmarshal(xmlStreamReader, classToFill);
                closeXMLStreamReader(xmlStreamReader);
            }

            releaseJAXBUnmarshaller(context, unmarshaller);
        } catch (JAXBException e) {
            closeXMLStreamReader(xmlStreamReader);
            if (logger.isErrorEnabled()) {
                logger.error(Messages.getMessage("jaxbFailToUnmarshal", type.getName()), e); //$NON-NLS-1$
            }
            throw new WebApplicationException(e, Response.Status.BAD_REQUEST);
        } catch (EntityReferenceXMLStreamException e) {
            closeXMLStreamReader(xmlStreamReader);
            if (logger.isErrorEnabled()) {
                logger.error(Messages.getMessage("entityRefsNotSupported")); //$NON-NLS-1$
            }
            throw new WebApplicationException(e, Response.Status.BAD_REQUEST);
        } catch (XMLStreamException e) {
            closeXMLStreamReader(xmlStreamReader);
            throw new WebApplicationException(e, Response.Status.BAD_REQUEST);
        } catch (RuntimeException e) {
            closeXMLStreamReader(xmlStreamReader);
            throw new WebApplicationException(e, Response.Status.BAD_REQUEST);
        }
        return unmarshaledResource;
    }

    public long getSize(JAXBElement<?> t,
                        Class<?> type,
                        Type genericType,
                        Annotation[] annotations,
                        MediaType mediaType) {
        return -1;
    }

    public boolean isWriteable(Class<?> type,
                               Type genericType,
                               Annotation[] annotations,
                               MediaType mediaType) {
        return isJAXBElement(type, genericType) && isSupportedMediaType(mediaType);
    }

    public void writeTo(JAXBElement<?> t,
                        Class<?> type,
                        Type genericType,
                        Annotation[] annotations,
                        MediaType mediaType,
                        MultivaluedMap<String, Object> httpHeaders,
                        OutputStream entityStream) throws IOException, WebApplicationException {

        mediaType = MediaTypeUtils.setDefaultCharsetOnMediaTypeHeader(httpHeaders, mediaType);

        try {
            Class<?> declaredType = t.getDeclaredType();
            JAXBContext context = getContext(declaredType, mediaType);
            Marshaller marshaller = getJAXBMarshaller(declaredType, context, mediaType);

            // Use an OutputStream directly instead of a Writer for performance.
            marshaller.marshal(t, entityStream);

            releaseJAXBMarshaller(context, marshaller);
        } catch (JAXBException e) {
            if (logger.isErrorEnabled()) {
                logger.error(Messages.getMessage("jaxbFailToMarshal", t.getName()), e); //$NON-NLS-1$
            }
            throw new WebApplicationException(e, Response.Status.INTERNAL_SERVER_ERROR);
        }
    }
}