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| 1 | /* | ||
| 2 | * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package sun.net.www.http; | ||
| 27 | |||
| 28 | import java.io.IOException; | ||
| 29 | import java.io.NotSerializableException; | ||
| 30 | import java.util.ArrayList; | ||
| 31 | import java.util.HashMap; | ||
| 32 | import java.net.URL; | ||
| 33 | |||
| 34 | /** | ||
| 35 | * A class that implements a cache of idle Http connections for keep-alive | ||
| 36 | * | ||
| 37 | * @author Stephen R. Pietrowicz (NCSA) | ||
| 38 | * @author Dave Brown | ||
| 39 | */ | ||
| 40 | public class KeepAliveCache | ||
| 41 | extends HashMap<KeepAliveKey, ClientVector> | ||
| 42 | implements Runnable { | ||
| 43 | private static final long serialVersionUID = -2937172892064557949L; | ||
| 44 | |||
| 45 | /* maximum # keep-alive connections to maintain at once | ||
| 46 | * This should be 2 by the HTTP spec, but because we don't support pipe-lining | ||
| 47 | * a larger value is more appropriate. So we now set a default of 5, and the value | ||
| 48 | * refers to the number of idle connections per destination (in the cache) only. | ||
| 49 | * It can be reset by setting system property "http.maxConnections". | ||
| 50 | */ | ||
| 51 | static final int MAX_CONNECTIONS = 5; | ||
| 52 | static int result = -1; | ||
| 53 | static int getMaxConnections() { | ||
| 54 | if (result == -1) { | ||
| 55 | result = java.security.AccessController.doPrivileged( | ||
| 56 | new sun.security.action.GetIntegerAction("http.maxConnections", | ||
| 57 | MAX_CONNECTIONS)) | ||
| 58 | .intValue(); | ||
| 59 | if (result <= 0) | ||
| 60 | result = MAX_CONNECTIONS; | ||
| 61 | } | ||
| 62 | return result; | ||
| 63 | } | ||
| 64 | |||
| 65 | static final int LIFETIME = 5000; | ||
| 66 | |||
| 67 | private Thread keepAliveTimer = null; | ||
| 68 | |||
| 69 | /** | ||
| 70 | * Constructor | ||
| 71 | */ | ||
| 72 | public KeepAliveCache() {} | ||
| 73 | |||
| 74 | /** | ||
| 75 | * Register this URL and HttpClient (that supports keep-alive) with the cache | ||
| 76 | * @param url The URL contains info about the host and port | ||
| 77 | * @param http The HttpClient to be cached | ||
| 78 | */ | ||
| 79 | public synchronized void put(final URL url, Object obj, HttpClient http) { | ||
| 80 | boolean startThread = (keepAliveTimer == null); | ||
| 81 | if (!startThread) { | ||
| 82 | if (!keepAliveTimer.isAlive()) { | ||
| 83 | startThread = true; | ||
| 84 | } | ||
| 85 | } | ||
| 86 | if (startThread) { | ||
| 87 | clear(); | ||
| 88 | /* Unfortunately, we can't always believe the keep-alive timeout we got | ||
| 89 | * back from the server. If I'm connected through a Netscape proxy | ||
| 90 | * to a server that sent me a keep-alive | ||
| 91 | * time of 15 sec, the proxy unilaterally terminates my connection | ||
| 92 | * The robustness to get around this is in HttpClient.parseHTTP() | ||
| 93 | */ | ||
| 94 | final KeepAliveCache cache = this; | ||
| 95 | java.security.AccessController.doPrivileged( | ||
| 96 | new java.security.PrivilegedAction<Void>() { | ||
| 97 | public Void run() { | ||
| 98 | // We want to create the Keep-Alive-Timer in the | ||
| 99 | // system threadgroup | ||
| 100 | ThreadGroup grp = Thread.currentThread().getThreadGroup(); | ||
| 101 | ThreadGroup parent = null; | ||
| 102 | while ((parent = grp.getParent()) != null) { | ||
| 103 | grp = parent; | ||
| 104 | } | ||
| 105 | |||
| 106 | keepAliveTimer = new Thread(grp, cache, "Keep-Alive-Timer"); | ||
| 107 | keepAliveTimer.setDaemon(true); | ||
| 108 | keepAliveTimer.setPriority(Thread.MAX_PRIORITY - 2); | ||
| 109 | // Set the context class loader to null in order to avoid | ||
| 110 | // keeping a strong reference to an application classloader. | ||
| 111 | keepAliveTimer.setContextClassLoader(null); | ||
| 112 | keepAliveTimer.start(); | ||
| 113 | return null; | ||
| 114 | } | ||
| 115 | }); | ||
| 116 | } | ||
| 117 | |||
| 118 | KeepAliveKey key = new KeepAliveKey(url, obj); | ||
| 119 | ClientVector v = super.get(key); | ||
| 120 | |||
| 121 | if (v == null) { | ||
| 122 | int keepAliveTimeout = http.getKeepAliveTimeout(); | ||
| 123 | v = new ClientVector(keepAliveTimeout > 0? | ||
| 124 | keepAliveTimeout*1000 : LIFETIME); | ||
| 125 | v.put(http); | ||
| 126 | super.put(key, v); | ||
| 127 | } else { | ||
| 128 | v.put(http); | ||
| 129 | } | ||
| 130 | } | ||
| 131 | |||
| 132 | /* remove an obsolete HttpClient from its VectorCache */ | ||
| 133 | public synchronized void remove (HttpClient h, Object obj) { | ||
| 134 | KeepAliveKey key = new KeepAliveKey(h.url, obj); | ||
| 135 | ClientVector v = super.get(key); | ||
| 136 | if (v != null) { | ||
| 137 | v.remove(h); | ||
| 138 | if (v.empty()) { | ||
| 139 | removeVector(key); | ||
| 140 | } | ||
| 141 | } | ||
| 142 | } | ||
| 143 | |||
| 144 | /* called by a clientVector thread when all its connections have timed out | ||
| 145 | * and that vector of connections should be removed. | ||
| 146 | */ | ||
| 147 | synchronized void removeVector(KeepAliveKey k) { | ||
| 148 | super.remove(k); | ||
| 149 | } | ||
| 150 | |||
| 151 | /** | ||
| 152 | * Check to see if this URL has a cached HttpClient | ||
| 153 | */ | ||
| 154 | public synchronized HttpClient get(URL url, Object obj) { | ||
| 155 | |||
| 156 | KeepAliveKey key = new KeepAliveKey(url, obj); | ||
| 157 | ClientVector v = super.get(key); | ||
| 158 | if (v == null) { // nothing in cache yet | ||
| 159 | return null; | ||
| 160 | } | ||
| 161 | return v.get(); | ||
| 162 | } | ||
| 163 | |||
| 164 | /* Sleeps for an alloted timeout, then checks for timed out connections. | ||
| 165 | * Errs on the side of caution (leave connections idle for a relatively | ||
| 166 | * short time). | ||
| 167 | */ | ||
| 168 | @Override | ||
| 169 | public void run() { | ||
| 170 | do { | ||
| 171 | try { | ||
| 172 | Thread.sleep(LIFETIME); | ||
| 173 | } catch (InterruptedException e) {} | ||
| 174 | synchronized (this) { | ||
| 175 | /* Remove all unused HttpClients. Starting from the | ||
| 176 | * bottom of the stack (the least-recently used first). | ||
| 177 | * REMIND: It'd be nice to not remove *all* connections | ||
| 178 | * that aren't presently in use. One could have been added | ||
| 179 | * a second ago that's still perfectly valid, and we're | ||
| 180 | * needlessly axing it. But it's not clear how to do this | ||
| 181 | * cleanly, and doing it right may be more trouble than it's | ||
| 182 | * worth. | ||
| 183 | */ | ||
| 184 | |||
| 185 | long currentTime = System.currentTimeMillis(); | ||
| 186 | |||
| 187 | ArrayList<KeepAliveKey> keysToRemove | ||
| 188 | = new ArrayList<KeepAliveKey>(); | ||
| 189 | |||
| 190 | for (KeepAliveKey key : keySet()) { | ||
| 191 | ClientVector v = get(key); | ||
| 192 | synchronized (v) { | ||
| 193 | int i; | ||
| 194 | |||
| 195 | for (i = 0; i < v.size(); i++) { | ||
| 196 | KeepAliveEntry e = v.elementAt(i); | ||
| 197 | if ((currentTime - e.idleStartTime) > v.nap) { | ||
| 198 | HttpClient h = e.hc; | ||
| 199 | h.closeServer(); | ||
| 200 | } else { | ||
| 201 | break; | ||
| 202 | } | ||
| 203 | } | ||
| 204 | v.subList(0, i).clear(); | ||
| 205 | |||
| 206 | if (v.size() == 0) { | ||
| 207 | keysToRemove.add(key); | ||
| 208 | } | ||
| 209 | } | ||
| 210 | } | ||
| 211 | |||
| 212 | for (KeepAliveKey key : keysToRemove) { | ||
| 213 | removeVector(key); | ||
| 214 | } | ||
| 215 | } | ||
| 216 | } while (size() > 0); | ||
| 217 | |||
| 218 | return; | ||
| 219 | } | ||
| 220 | |||
| 221 | /* | ||
| 222 | * Do not serialize this class! | ||
| 223 | */ | ||
| 224 | private void writeObject(java.io.ObjectOutputStream stream) | ||
| 225 | throws IOException { | ||
| 226 | throw new NotSerializableException(); | ||
| 227 | } | ||
| 228 | |||
| 229 | private void readObject(java.io.ObjectInputStream stream) | ||
| 230 | throws IOException, ClassNotFoundException { | ||
| 231 | throw new NotSerializableException(); | ||
| 232 | } | ||
| 233 | } | ||
| 234 | |||
| 235 | /* FILO order for recycling HttpClients, should run in a thread | ||
| 236 | * to time them out. If > maxConns are in use, block. | ||
| 237 | */ | ||
| 238 | |||
| 239 | |||
| 240 | class ClientVector extends java.util.Stack<KeepAliveEntry> { | ||
| 241 | private static final long serialVersionUID = -8680532108106489459L; | ||
| 242 | |||
| 243 | // sleep time in milliseconds, before cache clear | ||
| 244 | int nap; | ||
| 245 | |||
| 246 | |||
| 247 | |||
| 248 | ClientVector (int nap) { | ||
| 249 | this.nap = nap; | ||
| 250 | } | ||
| 251 | |||
| 252 | synchronized HttpClient get() { | ||
| 253 | if (empty()) { | ||
| 254 | return null; | ||
| 255 | } else { | ||
| 256 | // Loop until we find a connection that has not timed out | ||
| 257 | HttpClient hc = null; | ||
| 258 | long currentTime = System.currentTimeMillis(); | ||
| 259 | do { | ||
| 260 | KeepAliveEntry e = pop(); | ||
| 261 | if ((currentTime - e.idleStartTime) > nap) { | ||
| 262 | e.hc.closeServer(); | ||
| 263 | } else { | ||
| 264 | hc = e.hc; | ||
| 265 | } | ||
| 266 | } while ((hc== null) && (!empty())); | ||
| 267 | return hc; | ||
| 268 | } | ||
| 269 | } | ||
| 270 | |||
| 271 | /* return a still valid, unused HttpClient */ | ||
| 272 | synchronized void put(HttpClient h) { | ||
| 273 | if (size() >= KeepAliveCache.getMaxConnections()) { | ||
| 274 | h.closeServer(); // otherwise the connection remains in limbo | ||
| 275 | } else { | ||
| 276 | push(new KeepAliveEntry(h, System.currentTimeMillis())); | ||
| 277 | } | ||
| 278 | } | ||
| 279 | |||
| 280 | /* | ||
| 281 | * Do not serialize this class! | ||
| 282 | */ | ||
| 283 | private void writeObject(java.io.ObjectOutputStream stream) | ||
| 284 | throws IOException { | ||
| 285 | throw new NotSerializableException(); | ||
| 286 | } | ||
| 287 | |||
| 288 | private void readObject(java.io.ObjectInputStream stream) | ||
| 289 | throws IOException, ClassNotFoundException { | ||
| 290 | throw new NotSerializableException(); | ||
| 291 | } | ||
| 292 | } | ||
| 293 | |||
| 294 | |||
| 295 | class KeepAliveKey { | ||
| 296 | private String protocol = null; | ||
| 297 | private String host = null; | ||
| 298 | private int port = 0; | ||
| 299 | private Object obj = null; // additional key, such as socketfactory | ||
| 300 | |||
| 301 | /** | ||
| 302 | * Constructor | ||
| 303 | * | ||
| 304 | * @param url the URL containing the protocol, host and port information | ||
| 305 | */ | ||
| 306 | public KeepAliveKey(URL url, Object obj) { | ||
| 307 | this.protocol = url.getProtocol(); | ||
| 308 | this.host = url.getHost(); | ||
| 309 | this.port = url.getPort(); | ||
| 310 | this.obj = obj; | ||
| 311 | } | ||
| 312 | |||
| 313 | /** | ||
| 314 | * Determine whether or not two objects of this type are equal | ||
| 315 | */ | ||
| 316 | @Override | ||
| 317 | public boolean equals(Object obj) { | ||
| 318 | if ((obj instanceof KeepAliveKey) == false) | ||
| 319 | return false; | ||
| 320 | KeepAliveKey kae = (KeepAliveKey)obj; | ||
| 321 | return host.equals(kae.host) | ||
| 322 | && (port == kae.port) | ||
| 323 | && protocol.equals(kae.protocol) | ||
| 324 | && this.obj == kae.obj; | ||
| 325 | } | ||
| 326 | |||
| 327 | /** | ||
| 328 | * The hashCode() for this object is the string hashCode() of | ||
| 329 | * concatenation of the protocol, host name and port. | ||
| 330 | */ | ||
| 331 | @Override | ||
| 332 | public int hashCode() { | ||
| 333 | String str = protocol+host+port; | ||
| 334 | return this.obj == null? str.hashCode() : | ||
| 335 | str.hashCode() + this.obj.hashCode(); | ||
| 336 | } | ||
| 337 | } | ||
| 338 | |||
| 339 | class KeepAliveEntry { | ||
| 340 | HttpClient hc; | ||
| 341 | long idleStartTime; | ||
| 342 | |||
| 343 | KeepAliveEntry(HttpClient hc, long idleStartTime) { | ||
| 344 | this.hc = hc; | ||
| 345 | this.idleStartTime = idleStartTime; | ||
| 346 | } | ||
| 347 | } | ||