Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.lucene.gdata.servlet.handler; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.lucene.gdata.data.GDataAccount; import org.apache.lucene.gdata.data.ServerBaseFeed; import org.apache.lucene.gdata.data.GDataAccount.AccountRole; import org.apache.lucene.gdata.server.GDataEntityBuilder; import org.apache.lucene.gdata.server.GDataResponse; import org.apache.lucene.gdata.server.ServiceException; import org.apache.lucene.gdata.server.ServiceFactory; import org.apache.lucene.gdata.server.administration.AdminService; import org.apache.lucene.gdata.server.registry.ComponentType; import org.apache.lucene.gdata.server.registry.GDataServerRegistry; import org.apache.lucene.gdata.server.registry.ProvidedService; import com.google.gdata.util.ParseException; /** * * @author Simon Willnauer * */ public abstract class AbstractFeedHandler extends RequestAuthenticator implements GDataRequestHandler { private static final Log LOG = LogFactory.getLog(AbstractFeedHandler.class); protected static final String PARAMETER_ACCOUNT = "account"; protected static final String PARAMETER_SERVICE = "service"; private int error; protected boolean authenticated = false; private String errorMessage = ""; private boolean isError = false; /** * @see org.apache.lucene.gdata.servlet.handler.GDataRequestHandler#processRequest(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) */ @SuppressWarnings("unused") public void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.authenticated = authenticateAccount(request, AccountRole.FEEDAMINISTRATOR); if (!this.authenticated) setError(GDataResponse.UNAUTHORIZED, "Authorization failed"); } protected ServerBaseFeed createFeedFromRequest(HttpServletRequest request) throws ParseException, IOException, FeedHandlerException { GDataServerRegistry registry = GDataServerRegistry.getRegistry(); String providedService = request.getParameter(PARAMETER_SERVICE); if (!registry.isServiceRegistered(providedService)) { setError(GDataResponse.NOT_FOUND, "no such service"); throw new FeedHandlerException("ProvicdedService is not registered -- Name: " + providedService); } ProvidedService provServiceInstance = registry.getProvidedService(providedService); if (providedService == null) { setError(GDataResponse.BAD_REQUEST, "no such service"); throw new FeedHandlerException("no such service registered -- " + providedService); } try { ServerBaseFeed retVal = new ServerBaseFeed( GDataEntityBuilder.buildFeed(request.getReader(), provServiceInstance)); retVal.setServiceConfig(provServiceInstance); return retVal; } catch (IOException e) { if (LOG.isInfoEnabled()) LOG.info("Can not read from input stream - ", e); setError(GDataResponse.BAD_REQUEST, "Can not read from input stream"); throw e; } catch (ParseException e) { if (LOG.isInfoEnabled()) LOG.info("feed can not be parsed - ", e); setError(GDataResponse.BAD_REQUEST, "incoming feed can not be parsed"); throw e; } } protected GDataAccount createRequestedAccount(HttpServletRequest request) throws FeedHandlerException { GDataServerRegistry registry = GDataServerRegistry.getRegistry(); ServiceFactory serviceFactory = registry.lookup(ServiceFactory.class, ComponentType.SERVICEFACTORY); if (serviceFactory == null) { setError(GDataResponse.SERVER_ERROR, "Required server component not available"); throw new FeedHandlerException( "Required server component not available -- " + ServiceFactory.class.getName()); } AdminService service = serviceFactory.getAdminService(); String account = request.getParameter(PARAMETER_ACCOUNT); try { return service.getAccount(account); } catch (ServiceException e) { if (LOG.isInfoEnabled()) LOG.info("no account for requested account - " + account, e); setError(HttpServletResponse.SC_BAD_REQUEST, "no such account"); throw new FeedHandlerException(e.getMessage(), e); } } protected void sendResponse(HttpServletResponse response) { if (!this.isError) return; try { response.sendError(this.error, this.errorMessage); } catch (IOException e) { LOG.warn("can send error in RequestHandler ", e); } } protected void setError(int error, String message) { this.error = error; this.errorMessage = message; this.isError = true; } protected int getErrorCode() { return this.error; } protected String getErrorMessage() { return this.errorMessage; } static class FeedHandlerException extends Exception { /** * */ private static final long serialVersionUID = 1L; /** * Creates a new FeedHandlerException with a exception message and the exception cause this ex. * @param arg0 - the message * @param arg1 - the cause */ public FeedHandlerException(String arg0, Throwable arg1) { super(arg0, arg1); } /** * Creates a new FeedHandlerException with a exception message. * @param arg0 - message */ public FeedHandlerException(String arg0) { super(arg0); } } }