AtomEntryProvider.java

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 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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package org.apache.wink.common.internal.providers.entity.atom;

import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

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.ext.Provider;
import javax.ws.rs.ext.Providers;

import org.apache.wink.common.internal.providers.entity.xml.JAXBXmlProvider;
import org.apache.wink.common.internal.runtime.RuntimeContextTLS;
import org.apache.wink.common.internal.utils.MediaTypeUtils;
import org.apache.wink.common.model.atom.AtomContent;
import org.apache.wink.common.model.atom.AtomEntry;

@Provider
@Consumes( {MediaType.APPLICATION_ATOM_XML, MediaType.APPLICATION_JSON, MediaTypeUtils.JAVASCRIPT})
@Produces( {MediaType.APPLICATION_ATOM_XML, MediaType.APPLICATION_JSON, MediaTypeUtils.JAVASCRIPT})
public class AtomEntryProvider extends JAXBXmlProvider {

    @Override
    public boolean isReadable(Class<?> type,
                              Type genericType,
                              Annotation[] annotations,
                              MediaType mediaType) {
        return type == AtomEntry.class;
    }

    @Override
    public Object readFrom(Class<Object> type, Type genericType,
            Annotation[] annotations, MediaType mediaType,
            MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
            throws IOException, WebApplicationException {


        AtomEntry atomEntry = (AtomEntry) super.readFrom(type, genericType, annotations, mediaType, httpHeaders,
                entityStream);

        /*
         * The value in the AtomContent object is arbitrary, set by the server.  We want to use the
         * built-in AND client application supplied providers.  Because these providers are collected
         * on the thread local store, and the unmarshalling of the AtomContent value is done lazily
         * (after the client-server context has expired), we need some way to hold onto the Providers
         * long enough for the client app to be able to seamlessly get the value off the AtomContent
         * object.  Thus the need to set the *real* providers list on the AtomContent object, so it
         * can use the list to pass to ModelUtils when it needs to retrieve and unmarshal the AtomContent
         * value.
         * 
         * We have to be careful to use the real Providers list instead of the one from the injected
         * local providers field in this class.  The injected object may be a "proxy" to the real
         * providers, and could cause an infinite loop when ModelUtils.readValue calls back through
         * the providers.
         */
        AtomContent content = atomEntry.getContent();
        if (content != null) {
            content.setProviders(RuntimeContextTLS.getRuntimeContext().getAttribute(Providers.class));
        }

        return atomEntry;
    }

    @Override
    public boolean isWriteable(Class<?> type, Type genericType,
            Annotation[] annotations, MediaType mediaType) {
        return false;  // so JAXBXmlProvider will do the write
    }

}