Java tutorial
/** * The contents of this file are subject to the license and copyright * detailed in the LICENSE and NOTICE files at the root of the source * tree and available online at * * http://www.dspace.org/license/ */ package org.dspace.services.sessions; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Objects; import java.util.UUID; import java.util.concurrent.ConcurrentHashMap; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import org.apache.commons.lang.StringUtils; import org.dspace.kernel.mixins.InitializedService; import org.dspace.kernel.mixins.ShutdownService; import org.dspace.services.ConfigurationService; import org.dspace.services.RequestService; import org.dspace.services.model.Request; import org.dspace.services.model.RequestInterceptor; import org.dspace.services.model.RequestInterceptor.RequestInterruptionException; import org.dspace.services.sessions.model.HttpRequestImpl; import org.dspace.services.sessions.model.InternalRequestImpl; import org.dspace.utils.servicemanager.OrderedServiceComparator; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Required; /** * Implementation of the session service. * <p> * This depends on having something (a filter typically) which is * placing the current requests into a request storage cache. * <p> * * @author Aaron Zeckoski (azeckoski @ gmail.com) * @author Tom Desair (tom dot desair at atmire dot com) */ public final class StatelessRequestServiceImpl implements RequestService, InitializedService, ShutdownService { private static Logger log = LoggerFactory.getLogger(StatelessRequestServiceImpl.class); private ConfigurationService configurationService; @Autowired @Required public void setConfigurationService(ConfigurationService configurationService) { this.configurationService = configurationService; } /** * map for holding onto the request interceptors which is classloader safe. */ private Map<String, RequestInterceptor> interceptorsMap = new HashMap<String, RequestInterceptor>(); /* (non-Javadoc) * @see org.dspace.kernel.mixins.InitializedService#init() */ public void init() { log.info("init"); } /* (non-Javadoc) * @see org.dspace.kernel.mixins.ShutdownService#shutdown() */ public void shutdown() { log.info("shutdown"); clear(); } /** * Clears out the settings inside this service. * Mostly for testing. */ public void clear() { // immediately clear all interceptors when the service is terminated this.requests.clear(); this.interceptorsMap.clear(); } /* (non-Javadoc) * @see org.dspace.services.RequestService#startRequest() */ public String startRequest() { return startRequest(new InternalRequestImpl()); } /* (non-Javadoc) * @see org.dspace.services.RequestService#startRequest() */ public String startRequest(ServletRequest request, ServletResponse response) { return startRequest(new HttpRequestImpl(request, response)); } private String startRequest(Request req) { // call the list of interceptors List<RequestInterceptor> interceptors = getInterceptors(false); for (RequestInterceptor requestInterceptor : interceptors) { if (requestInterceptor != null) { try { requestInterceptor.onStart(req.getRequestId()); } catch (RequestInterruptionException e) { String message = "Request stopped from starting by exception from the interceptor (" + requestInterceptor + "): " + e.getMessage(); log.warn(message); throw new RequestInterruptionException(message, e); } catch (Exception e) { log.warn("Request interceptor (" + requestInterceptor + ") failed to execute on start (" + req.getRequestId() + "): " + e.getMessage()); } } } requests.setCurrent(req); return req.getRequestId(); } /* (non-Javadoc) * @see org.dspace.services.RequestService#endRequest(java.lang.Exception) */ public String endRequest(Exception failure) { String requestId = null; try { requestId = getCurrentRequestId(); if (StringUtils.isEmpty(requestId)) { // request not found, just log a warning log.debug("Attempting to end a request when none currently exists"); } else { endRequest(requestId, failure); } } finally { requests.removeCurrent(); } return requestId; } private void endRequest(String requestId, Exception failure) { if (requestId != null) { List<RequestInterceptor> interceptors = getInterceptors(true); // reverse for (RequestInterceptor requestInterceptor : interceptors) { if (requestInterceptor != null) { try { requestInterceptor.onEnd(requestId, (failure == null), failure); } catch (RequestInterruptionException e) { log.warn("Attempt to stop request from ending by an exception from the interceptor (" + requestInterceptor + "), cannot stop requests from ending though so request end " + "continues, this may be an error: " + e.getMessage()); } catch (Exception e) { log.warn("Request interceptor (" + requestInterceptor + ") failed to execute on end (" + requestId + "): " + e.getMessage()); } } } } } /** * List this session's interceptors. * * @param reverse return the list in reverse order? * @return the current list of interceptors in the correct order */ private List<RequestInterceptor> getInterceptors(boolean reverse) { ArrayList<RequestInterceptor> l = new ArrayList<RequestInterceptor>(this.interceptorsMap.values()); OrderedServiceComparator comparator = new OrderedServiceComparator(); Collections.sort(l, comparator); if (reverse) { Collections.reverse(l); } return l; } /* (non-Javadoc) * @see org.dspace.services.RequestService#registerRequestListener(org.dspace.services.model.RequestInterceptor) */ public void registerRequestInterceptor(RequestInterceptor interceptor) { if (interceptor == null) { throw new IllegalArgumentException("Cannot register an interceptor that is null"); } if (interceptor.getOrder() <= 0) { throw new IllegalArgumentException( "Interceptor ordering for RequestInterceptor's must be greater than 0"); } String key = interceptor.getOrder() + ":" + interceptor.getClass().getName(); this.interceptorsMap.put(key, interceptor); } /** * (non-Javadoc) * * @see org.dspace.services.RequestService#getCurrentUserId() */ public String getCurrentUserId() { Request currentRequest = getCurrentRequest(); if (currentRequest == null) { return null; } else { return Objects.toString(currentRequest.getAttribute(AUTHENTICATED_EPERSON)); } } /** * (non-Javadoc) * * @see org.dspace.services.RequestService#setCurrentUserId() */ public void setCurrentUserId(UUID epersonId) { Request currentRequest = getCurrentRequest(); if (currentRequest != null) { getCurrentRequest().setAttribute(AUTHENTICATED_EPERSON, epersonId); } } /* (non-Javadoc) * @see org.dspace.services.RequestService#getCurrentRequestId() */ public String getCurrentRequestId() { Request req = requests.getCurrent(); if (req != null) { return req.getRequestId(); } return null; } /* (non-Javadoc) * @see org.dspace.services.RequestService#getCurrentRequest() */ public Request getCurrentRequest() { return requests.getCurrent(); } /** * Class to hold the current request. Uses Map keyed on current thread id. */ private class RequestHolder { Map<Long, Request> requestMap = new ConcurrentHashMap<Long, Request>(); Request getCurrent() { return requestMap.get(Thread.currentThread().getId()); } void setCurrent(Request req) { requestMap.put(Thread.currentThread().getId(), req); } void removeCurrent() { requestMap.remove(Thread.currentThread().getId()); } Request get(String requestId) { if (!StringUtils.isEmpty(requestId)) { for (Request req : requestMap.values()) { if (req != null && requestId.equals(req.getRequestId())) { return req; } } } return null; } void remove(String requestId) { if (!StringUtils.isEmpty(requestId)) { for (Map.Entry<Long, Request> reqEntry : requestMap.entrySet()) { if (reqEntry.getValue() != null && requestId.equals(reqEntry.getValue().getRequestId())) { requestMap.remove(reqEntry.getKey()); } } } } void clear() { for (Request request : requestMap.values()) { try { endRequest(request.getRequestId(), null); } catch (RuntimeException e) { log.error("Runtime exception ending request", e); } catch (Exception e) { log.error("Exception ending request", e); } } requestMap.clear(); } } private RequestHolder requests = new RequestHolder(); }