AbstractResource.java

/*******************************************************************************
 * Copyright (c) 2006-2011 Gluster, Inc. <http://www.gluster.com>
 * This file is part of Gluster Management Gateway.
 *
 * Gluster Management Gateway 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.
 *
 * Gluster Management Gateway 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
 * <http://www.gnu.org/licenses/>.
 *******************************************************************************/
package org.gluster.storage.management.gateway.resources.v1_0;

import java.io.IOException;
import java.io.OutputStream;
import java.net.URI;

import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import javax.ws.rs.core.StreamingOutput;
import javax.ws.rs.core.UriInfo;

/**
 *
 */
public class AbstractResource {
	@Context
	protected UriInfo uriInfo;

	/**
	 * Creates a response with HTTP status code of 201 (created) and sets the "location" header to the URI created using
	 * the given path relative to current path.
	 * 
	 * @param relativePath
	 *            relative path of the created resource - will be set in the "location" header of response.
	 * @return the {@link Response} object
	 */
	protected Response createdResponse(String relativePath) {
		return Response.created(createRelativeURI(relativePath)).build();
	}

	/**
	 * Creates a response with HTTP status code of 204 (no content)
	 * @return the {@link Response} object
	 */
	protected Response noContentResponse() {
		return Response.noContent().build();
	}

	/**
	 * Creates a response with HTTP status code of 202 (accepted), also setting the location header to given location.
	 * This is typically done while triggering long running tasks
	 * 
	 * @param locationURI
	 *            URI to be appended to the base URI
	 * @return the {@link Response} object
	 */
	protected Response acceptedResponse(String locationURI) {
		return Response.status(Status.ACCEPTED).location(createAbsoluteURI(locationURI)).build();
	}

	/**
	 * Creates a response with HTTP status code of 404 (not found), also setting the given message in the response body
	 * 
	 * @param message
	 *            Message to be set in the response body
	 * @return the {@link Response} object
	 */
	protected Response notFoundResponse(String message) {
		return Response.status(Status.NOT_FOUND).type(MediaType.TEXT_HTML).entity(message).build();
	}

	/**
	 * Creates a new URI that is relative to the <b>base URI</b> of the application
	 * @param uriString URI String to be appended to the base URI
	 * @return newly created URI
	 */
	private URI createAbsoluteURI(String uriString) {
		return uriInfo.getBaseUriBuilder().path(uriString).build();
	}

	/**
	 * Creates a response with HTTP status code of 204 (no content), also setting the location header to given location
	 * @param location path of the location to be set relative to current path 
	 * @return the {@link Response} object
	 */
	protected Response noContentResponse(String location) {
		return Response.noContent().location(createRelativeURI(location)).build();
	}

	/**
	 * Creates a URI relative to current URI
	 * @param location path relative to current URI
	 * @return newly created URI
	 */
	protected URI createRelativeURI(String location) {
		return uriInfo.getAbsolutePathBuilder().path(location).build();
	}

	/**
	 * Creates a response with HTTP status code of 500 (internal server error) and sets the error message in the
	 * response body
	 * 
	 * @param errMessage
	 *            Error message to be set in the response body
	 * @return the {@link Response} object
	 */
	protected Response errorResponse(String errMessage) {
		return Response.serverError().type(MediaType.TEXT_HTML).entity(errMessage).build();
	}

	/**
	 * Creates a response with HTTP status code of 400 (bad request) and sets the error message in the
	 * response body
	 * 
	 * @param errMessage
	 *            Error message to be set in the response body
	 * @return the {@link Response} object
	 */
	protected Response badRequestResponse(String errMessage) {
		return Response.status(Status.BAD_REQUEST).type(MediaType.TEXT_HTML).entity(errMessage).build();
	}
	
	/**
	 * Creates a response with HTTP status code of 401 (unauthorized)
	 * 
	 * @return the {@link Response} object
	 */
	protected Response unauthorizedResponse() {
		return Response.status(Status.UNAUTHORIZED).build();
	}

	/**
	 * Creates an OK response and sets the entity in the response body.
	 * 
	 * @param entity
	 *            Entity to be set in the response body
	 * @param mediaType
	 *            Media type to be set on the response
	 * @return the {@link Response} object
	 */
	protected Response okResponse(Object entity, String mediaType) {
		return Response.ok(entity).type(mediaType).build();
	}

	/**
	 * Creates a streaming output response and sets the given streaming output in the response. Typically used for
	 * "download" requests
	 * 
	 * @param entity
	 *            Entity to be set in the response body
	 * @param mediaType
	 *            Media type to be set on the response
	 * @return the {@link Response} object
	 */
	protected Response streamingOutputResponse(StreamingOutput output) {
		return Response.ok(output).type(MediaType.APPLICATION_OCTET_STREAM).build();
	}
	
	protected StreamingOutput createStreamingOutput(final byte[] data) {
		return new StreamingOutput() {
			@Override
			public void write(OutputStream output) throws IOException {
				output.write(data);
			}
		};
	}
}