001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.activemq.transport.discovery.http; 018 019import java.io.IOException; 020import java.io.PrintWriter; 021import java.util.ArrayList; 022import java.util.Map; 023import java.util.concurrent.ConcurrentHashMap; 024import java.util.concurrent.ConcurrentMap; 025 026import javax.servlet.ServletException; 027import javax.servlet.http.HttpServlet; 028import javax.servlet.http.HttpServletRequest; 029import javax.servlet.http.HttpServletResponse; 030 031import org.slf4j.Logger; 032import org.slf4j.LoggerFactory; 033 034public class DiscoveryRegistryServlet extends HttpServlet { 035 private static final long serialVersionUID = 1L; 036 037 private static final Logger LOG = LoggerFactory.getLogger(HTTPDiscoveryAgent.class); 038 long maxKeepAge = 1000*60*60; // 1 hour. 039 ConcurrentMap<String, ConcurrentMap<String, Long>> serviceGroups = new ConcurrentHashMap<String, ConcurrentMap<String, Long>>(); 040 041 @Override 042 protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 043 String group = req.getPathInfo(); 044 String service = req.getHeader("service"); 045 LOG.debug("Registering: group="+group+", service="+service); 046 047 ConcurrentMap<String, Long> services = getServiceGroup(group); 048 services.put(service, System.currentTimeMillis()); 049 } 050 051 private ConcurrentMap<String, Long> getServiceGroup(String group) { 052 ConcurrentMap<String, Long> rc = serviceGroups.get(group); 053 if( rc == null ) { 054 rc = new ConcurrentHashMap<String, Long>(); 055 serviceGroups.put(group, rc); 056 } 057 return rc; 058 } 059 060 @Override 061 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 062 try { 063 long freshness = 1000*30; 064 String p = req.getParameter("freshness"); 065 if( p!=null ) { 066 freshness = Long.parseLong(p); 067 } 068 069 String group = req.getPathInfo(); 070 LOG.debug("group="+group); 071 ConcurrentMap<String, Long> services = getServiceGroup(group); 072 PrintWriter writer = resp.getWriter(); 073 074 long now = System.currentTimeMillis(); 075 long dropTime = now-maxKeepAge; 076 long minimumTime = now-freshness; 077 078 ArrayList<String> dropList = new ArrayList<String>(); 079 for (Map.Entry<String, Long> entry : services.entrySet()) { 080 if( entry.getValue() > minimumTime ) { 081 writer.println(entry.getKey()); 082 } else if( entry.getValue() < dropTime ) { 083 dropList.add(entry.getKey()); 084 } 085 } 086 087 // We might as well get rid of the really old entries. 088 for (String service : dropList) { 089 services.remove(service); 090 } 091 092 093 } catch (Exception e) { 094 resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Error occured: "+e); 095 } 096 } 097 098 @Override 099 protected void doDelete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 100 String group = req.getPathInfo(); 101 String service = req.getHeader("service"); 102 LOG.debug("Unregistering: group="+group+", service="+service); 103 104 ConcurrentMap<String, Long> services = getServiceGroup(group); 105 services.remove(service); 106 } 107 108}