net.java.dev.webdav.jaxrs.xml.WebDavContextResolver Maven / Gradle / Ivy

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/*
 * #%L
 * WebDAV Support for JAX-RS
 * %%
 * Copyright (C) 2008 - 2014 The java.net WebDAV Project
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public 
 * License along with this program.  If not, see
 * .
 * #L%
 */

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

import static javax.ws.rs.core.MediaType.APPLICATION_XML;

import javax.ws.rs.Produces;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.JAXBIntrospector;

import net.java.dev.webdav.util.Utilities;

/**
 * Provides support for custom extensions to WebDAV, like custom Properties and XML Elements.

 * 
 * 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.
 * 
 * @author Markus KARG ([email protected])
 * 
 * @see Chapter 17 "XML Extensibility in DAV" of RFC 2616
 *      "Hypertext Transfer Protocol -- HTTP/1.1"
 */
@Provider
@Produces(APPLICATION_XML)
public final class WebDavContextResolver implements ContextResolver {

	private final JAXBContext context;

	private final JAXBIntrospector introspector;

	/**
	 * 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.)
	 */
	public WebDavContextResolver(final Class... additionalClasses) throws JAXBException {
		this.context = WebDavJAXBContextBuilder.build(additionalClasses);
		this.introspector = this.context.createJAXBIntrospector();
	}

	/**
	 * @return A single, shared context for both, WebDAV XML Elements and Properties and custom extensions.
	 */
	@Override
	public final JAXBContext getContext(final Class cls) {
		return this.introspector.isElement(Utilities.buildInstanceOf(cls)) ? this.context : null;
	}

}