Java tutorial
/* ============================================================================ * * FILE: AsyncEventReceiver.java * The MIT License (MIT) Copyright (c) 2016 Sutanu Dalui Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * * ============================================================================ */ package com.reactivetechnologies.platform.rest; import java.io.IOException; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import javax.annotation.PostConstruct; import javax.ws.rs.ServiceUnavailableException; import org.jboss.netty.handler.codec.http.HttpResponseStatus; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import com.hazelcast.core.EntryEvent; import com.reactivetechnologies.platform.OperationsException; import com.reactivetechnologies.platform.datagrid.core.HazelcastClusterServiceBean; import com.reactivetechnologies.platform.datagrid.handlers.LocalMapEntryPutListener; import com.reactivetechnologies.platform.message.Event; import com.reactivetechnologies.platform.rest.rt.AsyncEventMapConfig; import com.reactivetechnologies.platform.rest.rt.SerializableHttpRequest; import com.reactivetechnologies.platform.utils.GsonWrapper; /** * Listener class for processing async REST invocations */ public class AsyncEventReceiverBean implements LocalMapEntryPutListener<Event<SerializableHttpRequest>> { private static final Logger log = LoggerFactory.getLogger(AsyncEventReceiverBean.class); public AsyncEventReceiverBean() { } @Override public void entryAdded(EntryEvent<Serializable, Event<SerializableHttpRequest>> event) { doHandle(event.getValue().getPayload(), event.getKey().toString()); } private final List<MethodInvocationHandler> getHandlers = new ArrayList<>(); private final List<MethodInvocationHandler> postHandlers = new ArrayList<>(); private final List<MethodInvocationHandler> deleteHandlers = new ArrayList<>(); /** * * @param request * @param mapId */ private void doHandle(SerializableHttpRequest request, String mapId) { try { processRequest(request, mapId); } catch (IOException e) { log.error("Unable to set response ", e); putResponse(mapId, "INTERNAL_SERVER_ERROR"); } catch (ReflectiveOperationException e) { log.error("Exception while invoking service method", e); putResponse(mapId, "INTERNAL_SERVER_ERROR"); } } @Autowired private GsonWrapper gson; @Autowired private HazelcastClusterServiceBean hzService; @PostConstruct private void init() { hzService.setMapConfiguration(AsyncEventMapConfig.class); hzService.addLocalEntryListener(this); } /** * Will be invoked from the {@linkplain DefaultAsyncResponse}. * @param id * @param returned */ void dispatchResponse(String id, Object returned) { try { if (returned instanceof Throwable) { log.warn(WebbitRestServerBean.ASYNC_REST_RESPONSE_PROCESS_ERR, (Throwable) returned); putResponse(id, WebbitRestServerBean.ASYNC_REST_RESPONSE_PROCESS_ERR + "[" + returned.getClass().getName() + "]"); } else { String jsonResponse = gson.get().toJson(returned); log.debug("Returning response JSON: " + jsonResponse); putResponse(id, jsonResponse); } } catch (Exception e) { log.error("Failed dispatching async response to cluster", e); } } private void processRequest(SerializableHttpRequest request, String id) throws IOException, ReflectiveOperationException { request.setImapKey(id); invokeServiceMethod(request); } /** * Check if the message processing is done * @param id * @return */ synchronized int getResponseCode(String id) { if (hzService.contains(id, WebbitRestServerBean.ASYNC_REST_EVENT_RESPONSE_MAP)) { String resp = (String) hzService.get(id, WebbitRestServerBean.ASYNC_REST_EVENT_RESPONSE_MAP); if (resp != null) { if (resp.contains(WebbitRestServerBean.ASYNC_REST_RESPONSE_PROCESS_ERR)) { if (resp.contains(ServiceUnavailableException.class.getName())) { return HttpResponseStatus.SERVICE_UNAVAILABLE.getCode(); } else { return HttpResponseStatus.INTERNAL_SERVER_ERROR.getCode(); } } else { return HttpResponseStatus.OK.getCode(); } } } if (hzService.contains(id, WebbitRestServerBean.ASYNC_REST_EVENT_MAP)) { return HttpResponseStatus.NO_CONTENT.getCode();//response not yet ready } return HttpResponseStatus.NOT_FOUND.getCode(); } /** * Gets the response * @param id * @return */ String getResponse(String id) { return (String) hzService.get(id, WebbitRestServerBean.ASYNC_REST_EVENT_RESPONSE_MAP); } private synchronized void putResponse(String id, String jsonResponse) { try { hzService.put(id, jsonResponse, WebbitRestServerBean.ASYNC_REST_EVENT_RESPONSE_MAP); hzService.remove(id, WebbitRestServerBean.ASYNC_REST_EVENT_MAP); log.info("Response committed.."); } catch (Exception e) { throw new IllegalArgumentException(id + "", e); } } private Object invokeIfMatch(MethodInvocationHandler handler, SerializableHttpRequest request) throws ReflectiveOperationException, OperationsException { if (handler.getMethod().getUri().matchesTemplate(request.getRequestUri())) { List<Object> args = new ArrayList<>(); args.add(new DefaultAsyncResponse(this, request.getImapKey())); args.addAll(request.getArgs()); return handler.invokeMethod(args.toArray()); } throw new OperationsException("No match found for- " + request.getRequestUri()); } private Object invokeServiceMethod(SerializableHttpRequest request) throws ReflectiveOperationException { switch (request.getRequestMethod()) { case "GET": for (MethodInvocationHandler handler : getGetHandlers()) { try { return invokeIfMatch(handler, request); } catch (OperationsException e) { continue; } } break; case "POST": for (MethodInvocationHandler handler : getPostHandlers()) { try { return invokeIfMatch(handler, request); } catch (OperationsException e) { continue; } } break; case "DELETE": for (MethodInvocationHandler handler : getDeleteHandlers()) { try { return invokeIfMatch(handler, request); } catch (OperationsException e) { continue; } } break; default: break; } throw new ReflectiveOperationException(new UnsupportedOperationException(request.getRequestMethod())); } @Override public void entryUpdated(EntryEvent<Serializable, Event<SerializableHttpRequest>> event) { //ignore since the response is being stored now } @Override public String keyspace() { return WebbitRestServerBean.ASYNC_REST_EVENT_MAP; } public List<MethodInvocationHandler> getPostHandlers() { return postHandlers; } public List<MethodInvocationHandler> getDeleteHandlers() { return deleteHandlers; } public List<MethodInvocationHandler> getGetHandlers() { return getHandlers; } }