WebDavContextResolver.java

/*
  Copyright 2011-2014 Red Hat, Inc

  This file is part of PressGang CCMS.

  PressGang CCMS 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 3 of the License, or
  (at your option) any later version.

  PressGang CCMS 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 PressGang CCMS.  If not, see <http://www.gnu.org/licenses/>.
*/

package net.java.dev.webdav.jaxrs.xml;

import net.java.dev.webdav.jaxrs.xml.conditions.*;
import net.java.dev.webdav.jaxrs.xml.elements.*;
import net.java.dev.webdav.jaxrs.xml.elements.Error;
import net.java.dev.webdav.jaxrs.xml.properties.*;

import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Provides support for custom extensions to WebDAV, like custom Properties and XML Elements.<br>
 *
 * WebDAV allows custom extensions for XML Elements and Properties. To enable JAX-RS to deal with these,
 * each of them must be implemented as a JAXB class and registered by passing it to the constructor of this resolver.
 *
 * This version of the class has been extended to provide the text/html mime type. This is required by tools like
 * perl-HTTP-DAV, which do not accept application/xml responses as valid WedDAV responses.
 *
 * The class itself and its methods are also not final, which prevents it from being used as a scanned resource in
 * RESTEasy.
 *
 * @author Markus KARG (mkarg@users.dev.java.net)
 * @see <a href="http://www.webdav.org/specs/rfc4918.html#xml-extensibility">Chapter 17 "XML Extensibility in DAV" of RFC 2616 "Hypertext Transfer Protocol -- HTTP/1.1"</a>
 */
@Provider
@Produces({MediaType.TEXT_XML, MediaType.APPLICATION_XML})
public class WebDavContextResolver implements ContextResolver<JAXBContext> {

    private final JAXBContext context;

    public WebDavContextResolver() throws JAXBException {
        this(null);
    }

    /**
     * Creates an instance of this resolver, registering the provided custom XML
     * Elements and Properties.
     *
     * @param additionalClasses The custom extensions (JAXB classes) to be registered (can be
     *                          left blank).
     * @throws JAXBException if an error was encountered while creating the JAXBContext,
     *                       such as (but not limited to): No JAXB implementation was
     *                       discovered, Classes use JAXB annotations incorrectly, Classes
     *                       have colliding annotations (i.e., two classes with the same
     *                       type name), The JAXB implementation was unable to locate
     *                       provider-specific out-of-band information (such as additional
     *                       files generated at the development time.)
     */
    @SuppressWarnings("unchecked")
    public WebDavContextResolver(final Class<?>... additionalClasses) throws JAXBException {
        final List<Class<?>> classesInContext = new ArrayList<Class<?>>(Arrays.asList(ActiveLock.class, AllProp.class, CannotModifyProtectedProperty.class,
                Collection.class, CreationDate.class, Depth.class, DisplayName.class, Error.class, Exclusive.class, GetContentLanguage.class,
                GetContentLength.class, GetContentType.class, GetETag.class, GetLastModified.class, HRef.class, Include.class, Location.class,
                LockDiscovery.class, LockEntry.class, LockInfo.class, LockRoot.class, LockScope.class, LockToken.class, LockTokenMatchesRequestUri.class,
                LockTokenSubmitted.class, LockType.class, MultiStatus.class, NoConflictingLock.class, NoExternalEntities.class, Owner.class,
                PreservedLiveProperties.class, Prop.class, PropertyUpdate.class, PropFind.class, PropFindFiniteDepth.class, PropName.class, PropStat.class,
                Remove.class, ResourceType.class, Response.class, ResponseDescription.class, Set.class, Shared.class, Status.class,
                SupportedLock.class, TimeOut.class, Write.class, FixedCreationDate.class));

        if (additionalClasses != null)
            classesInContext.addAll(Arrays.asList(additionalClasses));

        this.context = JAXBContext.newInstance(classesInContext.toArray(new Class[classesInContext.size()]));
    }

    /**
     * @return A single, shared context for both, WebDAV XML Elements and
     *         Properties and custom extensions.
     */
    @Override
    public JAXBContext getContext(final Class<?> cls) {

        if (cls.getPackage().getName().startsWith(WebDavContextResolver.class.getPackage().getName())) {
            return this.context;
        }

        return null;
    }

}