Showing the changes to java/pkg/sun/nio/fs/AbstractWatchKey.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,223 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (c) 2008, 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.nio.fs; | ||
| 27 | |||
| 28 | import java.nio.file.*; | ||
| 29 | import java.util.*; | ||
| 30 | |||
| 31 | /** | ||
| 32 | * Base implementation class for watch keys. | ||
| 33 | */ | ||
| 34 | |||
| 35 | abstract class AbstractWatchKey implements WatchKey { | ||
| 36 | |||
| 37 | /** | ||
| 38 | * Maximum size of event list (in the future this may be tunable) | ||
| 39 | */ | ||
| 40 | static final int MAX_EVENT_LIST_SIZE = 512; | ||
| 41 | |||
| 42 | /** | ||
| 43 | * Special event to signal overflow | ||
| 44 | */ | ||
| 45 | static final Event<Object> OVERFLOW_EVENT = | ||
| 46 | new Event<Object>(StandardWatchEventKinds.OVERFLOW, null); | ||
| 47 | |||
| 48 | /** | ||
| 49 | * Possible key states | ||
| 50 | */ | ||
| 51 | private static enum State { READY, SIGNALLED }; | ||
| 52 | |||
| 53 | // reference to watcher | ||
| 54 | private final AbstractWatchService watcher; | ||
| 55 | |||
| 56 | // reference to the original directory | ||
| 57 | private final Path dir; | ||
| 58 | |||
| 59 | // key state | ||
| 60 | private State state; | ||
| 61 | |||
| 62 | // pending events | ||
| 63 | private List<WatchEvent<?>> events; | ||
| 64 | |||
| 65 | // maps a context to the last event for the context (iff the last queued | ||
| 66 | // event for the context is an ENTRY_MODIFY event). | ||
| 67 | private Map<Object,WatchEvent<?>> lastModifyEvents; | ||
| 68 | |||
| 69 | protected AbstractWatchKey(Path dir, AbstractWatchService watcher) { | ||
| 70 | this.watcher = watcher; | ||
| 71 | this.dir = dir; | ||
| 72 | this.state = State.READY; | ||
| 73 | this.events = new ArrayList<WatchEvent<?>>(); | ||
| 74 | this.lastModifyEvents = new HashMap<Object,WatchEvent<?>>(); | ||
| 75 | } | ||
| 76 | |||
| 77 | final AbstractWatchService watcher() { | ||
| 78 | return watcher; | ||
| 79 | } | ||
| 80 | |||
| 81 | /** | ||
| 82 | * Return the original watchable (Path) | ||
| 83 | */ | ||
| 84 | @Override | ||
| 85 | public Path watchable() { | ||
| 86 | return dir; | ||
| 87 | } | ||
| 88 | |||
| 89 | /** | ||
| 90 | * Enqueues this key to the watch service | ||
| 91 | */ | ||
| 92 | final void signal() { | ||
| 93 | synchronized (this) { | ||
| 94 | if (state == State.READY) { | ||
| 95 | state = State.SIGNALLED; | ||
| 96 | watcher.enqueueKey(this); | ||
| 97 | } | ||
| 98 | } | ||
| 99 | } | ||
| 100 | |||
| 101 | /** | ||
| 102 | * Adds the event to this key and signals it. | ||
| 103 | */ | ||
| 104 | @SuppressWarnings("unchecked") | ||
| 105 | final void signalEvent(WatchEvent.Kind<?> kind, Object context) { | ||
| 106 | boolean isModify = (kind == StandardWatchEventKinds.ENTRY_MODIFY); | ||
| 107 | synchronized (this) { | ||
| 108 | int size = events.size(); | ||
| 109 | if (size > 0) { | ||
| 110 | // if the previous event is an OVERFLOW event or this is a | ||
| 111 | // repeated event then we simply increment the counter | ||
| 112 | WatchEvent<?> prev = events.get(size-1); | ||
| 113 | if ((prev.kind() == StandardWatchEventKinds.OVERFLOW) || | ||
| 114 | ((kind == prev.kind() && | ||
| 115 | Objects.equals(context, prev.context())))) | ||
| 116 | { | ||
| 117 | ((Event<?>)prev).increment(); | ||
| 118 | return; | ||
| 119 | } | ||
| 120 | |||
| 121 | // if this is a modify event and the last entry for the context | ||
| 122 | // is a modify event then we simply increment the count | ||
| 123 | if (!lastModifyEvents.isEmpty()) { | ||
| 124 | if (isModify) { | ||
| 125 | WatchEvent<?> ev = lastModifyEvents.get(context); | ||
| 126 | if (ev != null) { | ||
| 127 | assert ev.kind() == StandardWatchEventKinds.ENTRY_MODIFY; | ||
| 128 | ((Event<?>)ev).increment(); | ||
| 129 | return; | ||
| 130 | } | ||
| 131 | } else { | ||
| 132 | // not a modify event so remove from the map as the | ||
| 133 | // last event will no longer be a modify event. | ||
| 134 | lastModifyEvents.remove(context); | ||
| 135 | } | ||
| 136 | } | ||
| 137 | |||
| 138 | // if the list has reached the limit then drop pending events | ||
| 139 | // and queue an OVERFLOW event | ||
| 140 | if (size >= MAX_EVENT_LIST_SIZE) { | ||
| 141 | kind = StandardWatchEventKinds.OVERFLOW; | ||
| 142 | isModify = false; | ||
| 143 | context = null; | ||
| 144 | } | ||
| 145 | } | ||
| 146 | |||
| 147 | // non-repeated event | ||
| 148 | Event<Object> ev = | ||
| 149 | new Event<Object>((WatchEvent.Kind<Object>)kind, context); | ||
| 150 | if (isModify) { | ||
| 151 | lastModifyEvents.put(context, ev); | ||
| 152 | } else if (kind == StandardWatchEventKinds.OVERFLOW) { | ||
| 153 | // drop all pending events | ||
| 154 | events.clear(); | ||
| 155 | lastModifyEvents.clear(); | ||
| 156 | } | ||
| 157 | events.add(ev); | ||
| 158 | signal(); | ||
| 159 | } | ||
| 160 | } | ||
| 161 | |||
| 162 | @Override | ||
| 163 | public final List<WatchEvent<?>> pollEvents() { | ||
| 164 | synchronized (this) { | ||
| 165 | List<WatchEvent<?>> result = events; | ||
| 166 | events = new ArrayList<WatchEvent<?>>(); | ||
| 167 | lastModifyEvents.clear(); | ||
| 168 | return result; | ||
| 169 | } | ||
| 170 | } | ||
| 171 | |||
| 172 | @Override | ||
| 173 | public final boolean reset() { | ||
| 174 | synchronized (this) { | ||
| 175 | if (state == State.SIGNALLED && isValid()) { | ||
| 176 | if (events.isEmpty()) { | ||
| 177 | state = State.READY; | ||
| 178 | } else { | ||
| 179 | // pending events so re-queue key | ||
| 180 | watcher.enqueueKey(this); | ||
| 181 | } | ||
| 182 | } | ||
| 183 | return isValid(); | ||
| 184 | } | ||
| 185 | } | ||
| 186 | |||
| 187 | /** | ||
| 188 | * WatchEvent implementation | ||
| 189 | */ | ||
| 190 | private static class Event<T> implements WatchEvent<T> { | ||
| 191 | private final WatchEvent.Kind<T> kind; | ||
| 192 | private final T context; | ||
| 193 | |||
| 194 | // synchronize on watch key to access/increment count | ||
| 195 | private int count; | ||
| 196 | |||
| 197 | Event(WatchEvent.Kind<T> type, T context) { | ||
| 198 | this.kind = type; | ||
| 199 | this.context = context; | ||
| 200 | this.count = 1; | ||
| 201 | } | ||
| 202 | |||
| 203 | @Override | ||
| 204 | public WatchEvent.Kind<T> kind() { | ||
| 205 | return kind; | ||
| 206 | } | ||
| 207 | |||
| 208 | @Override | ||
| 209 | public T context() { | ||
| 210 | return context; | ||
| 211 | } | ||
| 212 | |||
| 213 | @Override | ||
| 214 | public int count() { | ||
| 215 | return count; | ||
| 216 | } | ||
| 217 | |||
| 218 | // for repeated events | ||
| 219 | void increment() { | ||
| 220 | count++; | ||
| 221 | } | ||
| 222 | } | ||
| 223 | } | ||