| 1 | /* |
| 2 | * @(#) $Id: AbstractProcessRunner.java,v 1.1.1.1 2006/03/19 06:09:42 rossen Exp $ |
| 3 | * |
| 4 | * Copyright (c) 2006, WebHydra.com |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions are met: |
| 9 | * |
| 10 | * * Redistributions of source code must retain the above copyright notice, |
| 11 | * this list of conditions and the following disclaimer. |
| 12 | * * Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * * Neither the name of the WebHydra.com nor the names of its contributors |
| 16 | * may be used to endorse or promote products derived from this software |
| 17 | * without specific prior written permission. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| 20 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| 23 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | package com.webhydra.slug.process; |
| 33 | |
| 34 | import com.webhydra.slug.SlugInitializationException; |
| 35 | import java.security.InvalidParameterException; |
| 36 | import java.util.ArrayList; |
| 37 | import java.util.Date; |
| 38 | import java.util.HashMap; |
| 39 | import java.util.Iterator; |
| 40 | import java.util.List; |
| 41 | import java.util.Map; |
| 42 | |
| 43 | /** |
| 44 | * Abstract Scheduler of the <code>SluggishProcess</code>es. |
| 45 | * @author rossen |
| 46 | */ |
| 47 | public abstract class AbstractProcessRunner extends AbstractSlugService implements ISlugRunner |
| 48 | { |
| 49 | |
| 50 | /** |
| 51 | * Active Process List (APL)<br> |
| 52 | * Holds map of <code>session</code>s and a map of their running processes. |
| 53 | * The user's <code>session</code> is used as a key to the a map of |
| 54 | * <code>PID</code>s and the corresponding <code>SluggishProces</code>. |
| 55 | */ |
| 56 | protected Map apl; |
| 57 | |
| 58 | /** |
| 59 | * Creates a new instance of AbstractProcessRunner |
| 60 | */ |
| 61 | protected AbstractProcessRunner() |
| 62 | { |
| 63 | apl = new HashMap(); |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * Find <code>SluggishProcess</code> in the Active Process List (APL) |
| 68 | * @param session current user session ID |
| 69 | * @param pid running Process ID (PID) |
| 70 | * @return <code>SluggishProcess</code> if found, otherwise - <code>null</code>. |
| 71 | */ |
| 72 | private SluggishProcess findProcess(String session, String pid) |
| 73 | { |
| 74 | if ((session == null) || (pid == null)) |
| 75 | { |
| 76 | return null; |
| 77 | } |
| 78 | Map pidSessions = (Map) apl.get(session); |
| 79 | if (pidSessions == null) |
| 80 | { |
| 81 | // session not found! |
| 82 | return null; |
| 83 | } |
| 84 | |
| 85 | return (SluggishProcess) pidSessions.get(pid); |
| 86 | } |
| 87 | |
| 88 | /** |
| 89 | * Checks process status |
| 90 | * @param session current user session ID. |
| 91 | * @param pid running Process ID (PID) |
| 92 | * @return current porcess status if process with provided <code>PID</code> exist in current <code>session</code>. |
| 93 | * If no process can be found then <code>null</code> is returned. |
| 94 | */ |
| 95 | public ProcessStatus checkProcess(String session, String pid) |
| 96 | { |
| 97 | if ((session == null) || (pid == null)) |
| 98 | { |
| 99 | return null; |
| 100 | } |
| 101 | SluggishProcess sp = findProcess(session, pid); |
| 102 | if (sp == null) |
| 103 | { |
| 104 | // process not found |
| 105 | return null; |
| 106 | } |
| 107 | return sp.getProcessStatus(); |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Remove specified process from the Active Process List (APL). |
| 112 | * If this is the last process for provided session then this session is removed from APL too. |
| 113 | * @param session current user session ID. |
| 114 | * @param pid Process ID (PID) to be removed. |
| 115 | * @return removed process or <code>null</code> if <code>PID</code> is not found. |
| 116 | */ |
| 117 | public SluggishProcess consumeProcess(String session, String pid) |
| 118 | { |
| 119 | if ((session == null) || (pid == null)) |
| 120 | { |
| 121 | return null; |
| 122 | } |
| 123 | SluggishProcess sp = findProcess(session, pid); |
| 124 | if (sp != null) |
| 125 | { |
| 126 | freeProcess(session, pid); |
| 127 | } |
| 128 | return sp; |
| 129 | } |
| 130 | |
| 131 | /** |
| 132 | * Cancel process |
| 133 | * Proces is signalled using SluggishProcess.cancel() and is removed from Active Process List (APL). |
| 134 | * @param session current user session ID. |
| 135 | * @param pid Process ID (PID) to be canceled. |
| 136 | * @return process or <code>null</code> if <code>PID</code> is not found. |
| 137 | */ |
| 138 | public SluggishProcess cancelProcess(String session, String pid) |
| 139 | { |
| 140 | if ((session == null) || (pid == null)) |
| 141 | { |
| 142 | return null; |
| 143 | } |
| 144 | SluggishProcess sp = findProcess(session, pid); |
| 145 | if (sp != null) |
| 146 | { |
| 147 | sp.cancel(); |
| 148 | freeProcess(session, pid); |
| 149 | } |
| 150 | return sp; |
| 151 | } |
| 152 | |
| 153 | /** |
| 154 | * Free Active Process List (APL) map from current PID. |
| 155 | * If this is the last <code>PID</code> for this <code>session</code> the <code>session</code> is removed too. |
| 156 | * @param session current user session ID. |
| 157 | * @param pid Process ID (PID) to be canceled. |
| 158 | */ |
| 159 | private void freeProcess(String session, String pid) |
| 160 | { |
| 161 | if (session != null) |
| 162 | { |
| 163 | synchronized (session) |
| 164 | { |
| 165 | Map pidSessions = (Map) apl.get(session); |
| 166 | if (pidSessions != null) |
| 167 | { |
| 168 | pidSessions.remove(pid); |
| 169 | if (pidSessions.isEmpty()) |
| 170 | cleanSession(session); |
| 171 | } |
| 172 | } |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * Remove all processes for specified session. |
| 178 | * @param session user's session ID to cleanup. |
| 179 | */ |
| 180 | public void cleanSession(String session) |
| 181 | { |
| 182 | if (session != null) |
| 183 | { |
| 184 | synchronized (apl) |
| 185 | { |
| 186 | Map sessionPids = (Map) apl.get(session); |
| 187 | if ((sessionPids != null) && !sessionPids.isEmpty()) |
| 188 | { |
| 189 | for (Iterator j = sessionPids.keySet().iterator(); j.hasNext();) |
| 190 | { |
| 191 | // try to safely cancel all processess if possible |
| 192 | Object pid = j.next(); |
| 193 | try |
| 194 | { |
| 195 | SluggishProcess sp = (SluggishProcess) sessionPids.get(pid); |
| 196 | sp.cancel(); |
| 197 | } |
| 198 | catch (Throwable t) {} // ignore it |
| 199 | j.remove(); |
| 200 | } |
| 201 | } |
| 202 | apl.remove(session); |
| 203 | } |
| 204 | } |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * Save a new SluggishProcess in to the Active Process List (<code>APL</code>). |
| 209 | * @param proc process to be executed. |
| 210 | * @param session current user session ID. |
| 211 | * @return Proccess ID (<code>PID</code>) assigned to provided process/session pair. |
| 212 | * @exception InvalidParameterException if any of the provided parameters is null. |
| 213 | */ |
| 214 | protected String save(SluggishProcess proc, String session) throws InvalidParameterException |
| 215 | { |
| 216 | if ((proc == null) || (session == null)) |
| 217 | { |
| 218 | throw new InvalidParameterException("Not null " + ((proc == null) ? "process" : "session" + " is required!")); |
| 219 | } |
| 220 | String pid = PidGenerator.newPid(); |
| 221 | synchronized (apl) |
| 222 | { |
| 223 | Map sessionPids = (Map) apl.get(session); |
| 224 | if (sessionPids == null) |
| 225 | { |
| 226 | sessionPids = new HashMap(); |
| 227 | } |
| 228 | sessionPids.put(pid, proc); |
| 229 | apl.put(session, sessionPids); |
| 230 | } |
| 231 | return pid; |
| 232 | } |
| 233 | |
| 234 | /** |
| 235 | * Returns estimated total number of sluggish processes in this runner instance. |
| 236 | * Since the execution of this method may take considerable time it is not synchronized |
| 237 | * and as a result the returned count is an estimate and may vary from the real |
| 238 | * process count at the moment. |
| 239 | * Another factor is the underlaying Map implementation which size() method |
| 240 | * returns Integer.MAX_VALUE when it has more than Integer.MAX_VALUE elements. |
| 241 | * @return the estimated count of all running and completed processes |
| 242 | * accomodated in this instance. |
| 243 | * @see java.util.Map#size() |
| 244 | */ |
| 245 | public long count() |
| 246 | { |
| 247 | long cnt = 0; |
| 248 | if (!apl.isEmpty()) |
| 249 | { |
| 250 | for (Iterator i = apl.keySet().iterator(); i.hasNext();) |
| 251 | { |
| 252 | Map m = (Map) apl.get(i.next()); |
| 253 | if (m != null) |
| 254 | cnt += m.size(); |
| 255 | } |
| 256 | } |
| 257 | return cnt; |
| 258 | } |
| 259 | |
| 260 | /** |
| 261 | * Cancels all running processes and removes them from this instance. |
| 262 | */ |
| 263 | public synchronized void clear() |
| 264 | { |
| 265 | List sessions = new ArrayList(apl.keySet()); |
| 266 | for (Iterator i = sessions.iterator(); i.hasNext();) |
| 267 | { |
| 268 | String sessionKey = (String) i.next(); |
| 269 | cleanSession(sessionKey); |
| 270 | } |
| 271 | } |
| 272 | |
| 273 | /** |
| 274 | * Default implementation. |
| 275 | * Si,pyt invoces <code>clean()</code>. |
| 276 | * @see #clear() |
| 277 | */ |
| 278 | public void release() { |
| 279 | super.release(); |
| 280 | clear(); |
| 281 | } |
| 282 | |
| 283 | /** |
| 284 | * Initialize the <code>APL</code> map |
| 285 | * @exception SlugInitializationException not really thrown |
| 286 | */ |
| 287 | public void prepare() throws SlugInitializationException { |
| 288 | super.prepare(); |
| 289 | apl = new HashMap(); |
| 290 | } |
| 291 | } |