AbstractJAXBElementProvider.java

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package com.sun.jersey.core.provider.jaxb;

import java.io.IOException;
import java.io.InputStream;
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.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response.Status;
import javax.ws.rs.ext.Providers;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.UnmarshalException;
import javax.xml.bind.Unmarshaller;

/**
 * An abstract provider for {@link JAXBElement}.
 * <p>
 * Implementing classes may extend this class to provide specific marshalling
 * and unmarshalling behaviour.
 * <p>
 * When unmarshalling a {@link UnmarshalException} will result in a
 * {@link WebApplicationException} being thrown with a status of 400
 * (Client error), and a {@link JAXBException} will result in a
 * {@link WebApplicationException} being thrown with a status of 500
 * (Internal Server error).
 * <p>
 * When marshalling a {@link JAXBException} will result in a
 * {@link WebApplicationException} being thrown with a status of 500
 * (Internal Server error).
 *
 * @author Paul.Sandoz@Sun.Com
 */
public abstract class AbstractJAXBElementProvider extends AbstractJAXBProvider<JAXBElement<?>> {    
    public AbstractJAXBElementProvider(Providers ps) {
        super(ps);
    }
    
    public AbstractJAXBElementProvider(Providers ps, MediaType mt) {
        super(ps, mt);        
    }
    
    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation annotations[], MediaType mediaType) {
        return type == JAXBElement.class && genericType instanceof ParameterizedType && isSupported(mediaType);
    }
    
    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation annotations[], MediaType mediaType) {
        return JAXBElement.class.isAssignableFrom(type) && isSupported(mediaType);
    }
            
    @Override
    public final JAXBElement<?> readFrom(
            Class<JAXBElement<?>> type, 
            Type genericType, 
            Annotation annotations[],
            MediaType mediaType, 
            MultivaluedMap<String, String> httpHeaders, 
            InputStream entityStream) throws IOException {
        final ParameterizedType pt = (ParameterizedType)genericType;
        final Class ta = (Class)pt.getActualTypeArguments()[0];
        
        try {
            return readFrom(ta, mediaType, getUnmarshaller(ta, mediaType), entityStream);
        } catch (UnmarshalException ex) {
            throw new WebApplicationException(ex, Status.BAD_REQUEST);
        } catch (JAXBException ex) {
            throw new WebApplicationException(ex, Status.INTERNAL_SERVER_ERROR);
        }    
    }

    protected abstract JAXBElement<?> readFrom(Class<?> type, MediaType mediaType,
            Unmarshaller u, InputStream entityStream)
            throws JAXBException;
    
    
    @Override
    public final void writeTo(
            JAXBElement<?> t, 
            Class<?> type, 
            Type genericType, 
            Annotation annotations[], 
            MediaType mediaType, 
            MultivaluedMap<String, Object> httpHeaders,
            OutputStream entityStream) throws IOException {
        try {
            final Marshaller m = getMarshaller(t.getDeclaredType(), mediaType);
            final Charset c = getCharset(mediaType);
            if (c != UTF8) {
                m.setProperty(Marshaller.JAXB_ENCODING, c.name());
            }
            setHeader(m, annotations);
            writeTo(t, mediaType, c, m, entityStream);
        } catch (JAXBException ex) {
            throw new WebApplicationException(ex, Status.INTERNAL_SERVER_ERROR);
        }
    }

    protected abstract void writeTo(JAXBElement<?> t, MediaType mediaType, Charset c,
            Marshaller m, OutputStream entityStream)
            throws JAXBException;
}