Java tutorial
package com.devicehive.websockets; /* * #%L * DeviceHive Frontend Logic * %% * Copyright (C) 2016 DataArt * %% * Licensed 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. * #L% */ import com.devicehive.configuration.Messages; import com.devicehive.exceptions.HiveException; import com.devicehive.websockets.converters.JsonMessageBuilder; import com.google.gson.JsonObject; import com.google.gson.JsonParseException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.security.access.AccessDeniedException; import org.springframework.security.authentication.BadCredentialsException; import org.springframework.stereotype.Component; import org.springframework.web.socket.WebSocketSession; import javax.persistence.OptimisticLockException; import javax.persistence.PersistenceException; import javax.servlet.http.HttpServletResponse; import javax.validation.ConstraintViolationException; @Component public class WebSocketResponseBuilder { private static final Logger logger = LoggerFactory.getLogger(WebSocketResponseBuilder.class); @Autowired private WebSocketRequestProcessor requestProcessor; public JsonObject buildResponse(JsonObject request, WebSocketSession session) { JsonObject response; try { response = requestProcessor.process(request, session).getResponseAsJson(); } catch (BadCredentialsException ex) { logger.error("Unauthorized access", ex); response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_UNAUTHORIZED, "Invalid credentials").build(); } catch (AccessDeniedException ex) { logger.error("Access to action is denied", ex); response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized").build(); } catch (HiveException ex) { logger.error("Error executing the request", ex); response = JsonMessageBuilder.createError(ex).build(); } catch (ConstraintViolationException ex) { logger.error("Error executing the request", ex); response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_BAD_REQUEST, ex.getMessage()).build(); } catch (org.hibernate.exception.ConstraintViolationException ex) { logger.error("Error executing the request", ex); response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_CONFLICT, ex.getMessage()).build(); } catch (JsonParseException ex) { logger.error("Error executing the request", ex); response = JsonMessageBuilder.createErrorResponseBuilder(HttpServletResponse.SC_BAD_REQUEST, Messages.INVALID_REQUEST_PARAMETERS).build(); } catch (OptimisticLockException ex) { logger.error("Error executing the request", ex); logger.error("Data conflict", ex); response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_CONFLICT, Messages.CONFLICT_MESSAGE).build(); } catch (PersistenceException ex) { if (ex.getCause() instanceof org.hibernate.exception.ConstraintViolationException) { response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_CONFLICT, ex.getMessage()).build(); } else { response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex.getMessage()) .build(); } } catch (Exception ex) { logger.error("Error executing the request", ex); response = JsonMessageBuilder .createErrorResponseBuilder(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex.getMessage()) .build(); } return new JsonMessageBuilder().addAction(request.get(JsonMessageBuilder.ACTION)) .addRequestId(request.get(JsonMessageBuilder.REQUEST_ID)).include(response).build(); } }