Java tutorial
/* * Copyright (c) 2010-2011 Lockheed Martin Corporation * * 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. */ package org.eurekastreams.server.service.restlets; import java.io.Serializable; import java.io.StringWriter; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.util.Date; import java.util.List; import javax.resource.spi.IllegalStateException; import net.sf.json.JSONObject; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.codehaus.jackson.JsonFactory; import org.codehaus.jackson.JsonGenerator; import org.codehaus.jackson.map.ObjectMapper; import org.eurekastreams.commons.actions.context.ClientPrincipalActionContextImpl; import org.eurekastreams.commons.actions.context.Principal; import org.eurekastreams.commons.actions.context.PrincipalActionContext; import org.eurekastreams.commons.actions.service.ServiceAction; import org.eurekastreams.commons.actions.service.TaskHandlerServiceAction; import org.eurekastreams.commons.exceptions.ExecutionException; import org.eurekastreams.commons.server.service.ActionController; import org.eurekastreams.server.persistence.mappers.cache.Transformer; import org.eurekastreams.server.service.actions.strategies.ApplicationContextHolder; import org.restlet.data.MediaType; import org.restlet.data.Request; import org.restlet.data.Status; import org.restlet.resource.Representation; import org.restlet.resource.ResourceException; import org.restlet.resource.StringRepresentation; import org.restlet.resource.Variant; import org.springframework.util.Assert; /** * Endpoint for the API (invoking actions). */ public class ActionResource extends SmpResource { /** Logger. */ private final Log log = LogFactory.getLog(ActionResource.class); /** Service Action Controller. */ private final ActionController serviceActionController; /** Principal populators. */ private final List<Transformer<Request, Principal>> principalExtractors; /** Client populators. */ private final List<Transformer<Request, String>> clientExtractors; /** JSON Factory for building JSON Generators. */ private final JsonFactory jsonFactory; /** Holds the app context. */ private final ApplicationContextHolder applicationContextHolder; /** Only allow read-only actions. */ private final boolean readOnly; /** * User principal. */ private Principal principal; /** * The action to execute. */ private String actionKey; /** * The request type. */ private String requestType; /** * Parameters to the restlet in JSON. Contains the request and any other needed data. */ private String paramsJSON; /** ID of client submitting the request. */ private String clientUniqueId; /** * Default constructor. * * @param inServiceActionController * the action controller. * @param inPrincipalExtractors * the principal extractors. * @param inClientExtractors * Strategies to extract the client. * @param inJsonFactory * the json factory. * @param inApplicationContextHolder * app context holder. * @param inReadOnly * Only allow read-only actions. */ public ActionResource(final ActionController inServiceActionController, final List<Transformer<Request, Principal>> inPrincipalExtractors, final List<Transformer<Request, String>> inClientExtractors, final JsonFactory inJsonFactory, final ApplicationContextHolder inApplicationContextHolder, final boolean inReadOnly) { serviceActionController = inServiceActionController; principalExtractors = inPrincipalExtractors; clientExtractors = inClientExtractors; jsonFactory = inJsonFactory; applicationContextHolder = inApplicationContextHolder; readOnly = inReadOnly; } /** * init the params. * * @param request * the request object. */ @Override protected void initParams(final Request request) { principal = getPrincipal(request); clientUniqueId = getClient(request); Assert.notNull(principal, "Principal object cannot be null."); actionKey = (String) request.getAttributes().get("action"); requestType = (String) request.getAttributes().get("requestType"); try { paramsJSON = URLDecoder.decode((String) request.getAttributes().get("paramsJSON"), "UTF-8"); } catch (UnsupportedEncodingException ex) { throw new ExecutionException(ex); } } /** * GET the activites. * * @param variant * the variant. * @return the JSON. * @throws ResourceException * the exception. */ @SuppressWarnings("unchecked") @Override public Representation represent(final Variant variant) throws ResourceException { String jsString = ""; try { // get the action Object springBean = applicationContextHolder.getContext().getBean(actionKey); // get parameter Serializable actionParameter = getRequestObject(); // create ServiceActionContext. PrincipalActionContext actionContext = new ClientPrincipalActionContextImpl(actionParameter, principal, clientUniqueId); actionContext.setActionId(actionKey); log.debug("executing action: " + actionKey + " for user: " + principal.getAccountId()); Serializable result = "empty result"; if (springBean instanceof ServiceAction) { ServiceAction action = (ServiceAction) springBean; if (readOnly && !action.isReadOnly()) { throw new IllegalStateException("Action requested is not read-only."); } result = serviceActionController.execute(actionContext, action); } else if (springBean instanceof TaskHandlerServiceAction) { TaskHandlerServiceAction action = (TaskHandlerServiceAction) springBean; if (readOnly && !action.isReadOnly()) { throw new IllegalStateException("Action requested is not read-only."); } result = serviceActionController.execute(actionContext, action); } StringWriter writer = new StringWriter(); JsonGenerator jsonGenerator = jsonFactory.createJsonGenerator(writer); jsonGenerator.writeObject(result); writer.close(); jsString = writer.toString(); } catch (Exception ex) { log.error("Error excecuting action " + actionKey + " from restlet.", ex); throw new ResourceException(Status.CLIENT_ERROR_BAD_REQUEST, "Error executing action."); } Representation rep = new StringRepresentation(jsString, MediaType.TEXT_PLAIN); rep.setExpirationDate(new Date(0L)); return rep; } /** * Returns Principal for given account id. * * @param inRequest * Request to get principal from. * @return Principal for given account id. */ private Principal getPrincipal(final Request inRequest) { for (Transformer<Request, Principal> extractor : principalExtractors) { Principal result = extractor.transform(inRequest); if (result != null) { return result; } } return null; } /** * Returns the client used for the request (if available). * * @param inRequest * Request to get client from. * @return Client for the current request. */ private String getClient(final Request inRequest) { for (Transformer<Request, String> extractor : clientExtractors) { String result = extractor.transform(inRequest); if (result != null) { return result; } } return null; } /** * Go from JSON to Request object. * * @return the request object. * @throws Exception * possible exceptions. */ @SuppressWarnings({ "rawtypes", "unchecked" }) private Serializable getRequestObject() throws Exception { if (requestType.toLowerCase().equals("null")) { return null; } final JSONObject paramsAsObject = JSONObject.fromObject(paramsJSON); if (requestType.toLowerCase().equals("long")) { return paramsAsObject.getLong("request"); } else if (requestType.toLowerCase().equals("int")) { return paramsAsObject.getInt("request"); } else if (requestType.toLowerCase().equals("string")) { return paramsAsObject.getString("request"); } else if (requestType.toLowerCase().equals("boolean")) { return paramsAsObject.getBoolean("request"); } else { Class returnType = Class.forName(requestType); String requestAsString = paramsAsObject.getString("request"); ObjectMapper objMapper = new ObjectMapper(); Object requestAsObject = objMapper.readValue(requestAsString, returnType); /* * This is nicer, but some of our types don't deserialize properly with it. JSONObject requestAsJson = * paramsAsObject.getJSONObject("request"); Object requestAsObject = JSONObject.toBean(requestAsJson, * returnType); */ return (Serializable) returnType.cast(requestAsObject); } } }