gvsig-scripting / org.gvsig.scripting / trunk / org.gvsig.scripting / org.gvsig.scripting.swing / org.gvsig.scripting.swing.impl / src / main / java / org / gvsig / scripting / swing / impl / FileChangesObserver.java @ 1267
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1 | 1267 | jjdelcerro | package org.gvsig.scripting.swing.impl; |
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2 | |||
3 | import java.io.File; |
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4 | import java.io.IOException; |
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5 | import java.lang.ref.WeakReference; |
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6 | import java.nio.file.FileSystem; |
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7 | import java.nio.file.FileSystems; |
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8 | import java.nio.file.Path; |
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9 | import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE; |
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10 | import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE; |
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11 | import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY; |
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12 | import static java.nio.file.StandardWatchEventKinds.OVERFLOW; |
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13 | import java.nio.file.WatchEvent; |
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14 | import java.nio.file.WatchKey; |
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15 | import java.nio.file.WatchService; |
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16 | import java.util.ArrayList; |
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17 | import java.util.HashMap; |
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18 | import java.util.List; |
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19 | import java.util.Map; |
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20 | import java.util.Objects; |
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21 | import org.gvsig.tools.observer.Observable; |
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22 | import org.gvsig.tools.observer.Observer; |
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23 | import org.slf4j.Logger; |
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24 | import org.slf4j.LoggerFactory; |
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25 | |||
26 | /**
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27 | *
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28 | * @author gvSIG Team
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29 | */
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30 | @SuppressWarnings("UseSpecificCatch") |
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31 | public class FileChangesObserver { |
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32 | private static final Logger LOGGER = LoggerFactory.getLogger(FileChangesObserver.class); |
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33 | |||
34 | private static FileChangesObserver INSTANCE = null; |
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35 | |||
36 | public static FileChangesObserver getInstance() { |
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37 | if (INSTANCE == null) { |
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38 | INSTANCE = new FileChangesObserver();
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39 | } |
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40 | return INSTANCE;
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41 | } |
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42 | |||
43 | private class FileObserver implements Observable { |
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44 | private final Path folder; |
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45 | private final WeakReference<Observer> observer; |
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46 | @SuppressWarnings("FieldMayBeFinal") |
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47 | private File file; |
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48 | |||
49 | public FileObserver(File file, Observer observer) { |
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50 | try {
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51 | this.file = file.getCanonicalFile();
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52 | } catch (IOException ex) { |
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53 | this.file = file.getAbsoluteFile();
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54 | } |
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55 | this.observer = new WeakReference<>(observer); |
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56 | FileSystem fs = FileSystems.getDefault(); |
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57 | if( file.isDirectory() ) {
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58 | this.folder = fs.getPath(file.getAbsolutePath());
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59 | } else {
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60 | this.folder = fs.getPath(file.getParentFile().getAbsolutePath());
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61 | } |
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62 | } |
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63 | |||
64 | public Path getFolder() {
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65 | return this.folder; |
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66 | } |
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67 | |||
68 | public File getFile() { |
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69 | return this.file; |
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70 | } |
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71 | |||
72 | public void notifyObserver() { |
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73 | // LOGGER.info("notifyObserver(): enter, ("+file.toString()+").");
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74 | Observer obs = this.observer.get(); |
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75 | if( obs == null ) { |
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76 | // LOGGER.info("notifyObserver(): exit, obs=null ("+file.toString()+").");
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77 | return;
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78 | } |
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79 | // LOGGER.info("notifyObserver(): obs="+obs.hashCode()+" ("+file.toString()+").");
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80 | obs.update(this, this.file); |
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81 | // LOGGER.info("notifyObserver(): exit, obs="+obs.hashCode()+" ("+file.toString()+").");
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82 | } |
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83 | |||
84 | private boolean is(Observer observer) { |
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85 | Observer obs = this.observer.get(); |
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86 | if( obs == null ) { |
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87 | return false; |
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88 | } |
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89 | return obs == observer; // Queremos comparar los punteros. |
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90 | } |
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91 | |||
92 | private boolean is(Observer observer, File file) { |
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93 | Observer obs = this.observer.get(); |
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94 | if( obs == null || obs != observer) { // Queremos comparar los punteros. |
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95 | return false; |
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96 | } |
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97 | return this.file.equals(file); |
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98 | } |
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99 | |||
100 | private boolean is(Path file) { |
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101 | File f = file.toAbsolutePath().toFile();
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102 | try {
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103 | f = f.getCanonicalFile(); |
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104 | } catch (IOException ex) { |
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105 | f = f.getAbsoluteFile(); |
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106 | } |
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107 | return this.file.equals(f); |
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108 | } |
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109 | |||
110 | private boolean isDead() { |
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111 | Observer obs = this.observer.get(); |
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112 | return obs == null; |
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113 | } |
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114 | |||
115 | @Override
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116 | public void addObserver(Observer obsrvr) { |
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117 | FileChangesObserver.this.addObserver(obsrvr, this.file);
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118 | } |
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119 | |||
120 | @Override
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121 | public void deleteObserver(Observer obsrvr) { |
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122 | FileChangesObserver.this.deleteObserver(obsrvr); |
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123 | } |
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124 | |||
125 | @Override
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126 | public void deleteObservers() { |
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127 | FileChangesObserver.this.deleteObservers(); |
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128 | } |
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129 | |||
130 | } |
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131 | |||
132 | |||
133 | private class Process extends Thread { |
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134 | private WatchService watcher;
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135 | private final Map<String,WatchKey> folders; |
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136 | |||
137 | public Process() { |
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138 | try {
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139 | this.watcher = FileSystems.getDefault().newWatchService();
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140 | } catch (Throwable ex) { |
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141 | LOGGER.warn("Can't create WatchService.", ex);
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142 | this.watcher = null; |
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143 | } |
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144 | this.folders = new HashMap<>(); |
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145 | this.setName("ScriptingFilesChangesObserver"); |
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146 | } |
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147 | |||
148 | @Override
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149 | public void run() { |
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150 | if( this.watcher == null ) { |
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151 | return;
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152 | } |
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153 | for (;;) {
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154 | // wait for key to be signaled
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155 | WatchKey key; |
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156 | try {
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157 | key = watcher.take(); |
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158 | } catch (InterruptedException x) { |
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159 | return;
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160 | } |
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161 | if( key == null ) { |
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162 | continue;
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163 | } |
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164 | Path folder = (Path) key.watchable(); |
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165 | if( !key.isValid() ) {
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166 | String pathname = folder.toFile().getAbsolutePath();
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167 | synchronized(folders) {
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168 | this.folders.remove(pathname);
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169 | } |
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170 | try {
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171 | key.cancel(); |
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172 | } catch(Throwable th) { |
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173 | LOGGER.debug("Cat cancel watch on '"+pathname+"'.",th); |
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174 | } |
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175 | continue;
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176 | } |
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177 | try {
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178 | for (WatchEvent<?> event : key.pollEvents()) {
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179 | WatchEvent.Kind<?> kind = event.kind(); |
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180 | // This key is registered only
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181 | // for ENTRY_CREATE events,
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182 | // but an OVERFLOW event can
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183 | // occur regardless if events
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184 | // are lost or discarded.
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185 | if (kind == OVERFLOW) {
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186 | continue;
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187 | } |
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188 | |||
189 | // The filename is the context of the event.
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190 | WatchEvent<Path> ev = (WatchEvent<Path>) event; |
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191 | Path filename = ev.context(); |
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192 | Path child = folder.resolve(filename); |
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193 | |||
194 | List<FileObserver>toNotify = new ArrayList<>(); |
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195 | synchronized(fileObservers) {
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196 | for (FileObserver fileObserver : fileObservers) {
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197 | if( fileObserver.is(child) ) {
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198 | toNotify.add(fileObserver); |
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199 | } |
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200 | } |
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201 | } |
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202 | for (FileObserver fileObserver : toNotify) {
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203 | fileObserver.notifyObserver(); |
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204 | } |
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205 | } |
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206 | } catch(Exception ex) { |
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207 | LOGGER.warn("Can't process watch event.", ex);
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208 | } finally {
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209 | // Reset the key -- this step is critical if you want to
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210 | // receive further watch events.
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211 | key.reset(); |
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212 | } |
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213 | } |
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214 | } |
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215 | |||
216 | public void reqisterWatch(Path folder) { |
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217 | // LOGGER.info("reqisterWatch(): enter, folder="+folder.hashCode()+", "+folder.toString()+".");
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218 | synchronized(folders) {
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219 | String pathname = folder.toFile().getAbsolutePath();
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220 | WatchKey watchkey = this.folders.get(pathname);
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221 | if( watchkey != null ) { |
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222 | return;
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223 | } |
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224 | try {
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225 | watchkey = folder.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY); |
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226 | this.folders.put(pathname, watchkey);
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227 | } catch (IOException x) { |
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228 | LOGGER.warn("Can't add watch on path '"+Objects.toString(folder), x);
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229 | } |
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230 | } |
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231 | // LOGGER.info("reqisterWatch(): exit, folder="+folder.hashCode()+", "+folder.toString()+".");
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232 | } |
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233 | |||
234 | public void cancelWatch(final Path folder) { |
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235 | // LOGGER.info("cancelWatch(): enter, folder="+folder.hashCode()+", "+folder.toString()+".");
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236 | synchronized(folders) {
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237 | String pathname = folder.toFile().getAbsolutePath();
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238 | WatchKey watchkey = this.folders.get(pathname);
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239 | if( watchkey == null ) { |
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240 | return;
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241 | } |
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242 | this.folders.remove(pathname);
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243 | try {
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244 | watchkey.cancel(); |
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245 | } catch(Throwable th) { |
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246 | LOGGER.debug("Cat cancel watch on '"+pathname+"'.",th); |
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247 | } |
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248 | } |
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249 | // LOGGER.info("cancelWatch(): exit, folder="+folder.hashCode()+", "+folder.toString()+".");
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250 | } |
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251 | |||
252 | } |
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253 | |||
254 | private final List<FileObserver> fileObservers; |
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255 | private final Process process; |
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256 | |||
257 | private FileChangesObserver() {
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258 | this.fileObservers = new ArrayList<>(); |
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259 | this.process = new Process(); |
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260 | this.process.start();
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261 | } |
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262 | |||
263 | private int getWatchCounts(Path folder) { |
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264 | int count = 0; |
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265 | for (FileObserver fo : fileObservers) {
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266 | if( folder.equals(fo.getFolder()) ) {
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267 | count++; |
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268 | } |
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269 | } |
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270 | return count;
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271 | } |
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272 | |||
273 | public void addObserver(final Observer observer, final File file) { |
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274 | // LOGGER.info("addObserver(): enter, observer="+observer.hashCode()+", f="+(file==null?"null":file.getAbsolutePath())+".");
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275 | synchronized(fileObservers) {
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276 | for (FileObserver fileObserver : fileObservers) {
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277 | if( fileObserver.is(observer,file) ) {
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278 | // LOGGER.info("addObserver(): exit, already registered, observer="+observer.hashCode()+", f="+(file==null?"null":file.getAbsolutePath())+".");
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279 | return;
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280 | } |
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281 | } |
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282 | removeDeads(); |
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283 | FileObserver fobserver = new FileObserver(file, observer);
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284 | this.process.reqisterWatch(fobserver.getFolder());
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285 | this.fileObservers.add(fobserver);
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286 | } |
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287 | // LOGGER.info("addObserver(): exit, observer="+observer.hashCode()+", f="+(file==null?"null":file.getAbsolutePath())+".");
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288 | } |
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289 | |||
290 | public void deleteObserver(final Observer observer) { |
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291 | // LOGGER.info("deleteObserver(): enter, observer="+observer.hashCode());
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292 | synchronized(fileObservers) {
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293 | for (FileObserver fileObserver : this.fileObservers) { |
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294 | if( fileObserver.is(observer) ) {
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295 | this.fileObservers.remove(fileObserver);
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296 | if( this.getWatchCounts(fileObserver.getFolder())<1 ) { |
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297 | this.process.cancelWatch(fileObserver.getFolder());
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298 | } |
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299 | return;
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300 | } |
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301 | } |
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302 | removeDeads(); |
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303 | } |
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304 | // LOGGER.info("deleteObserver(): exit, observer="+observer.hashCode());
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305 | } |
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306 | |||
307 | public synchronized void removeDeads() { |
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308 | // LOGGER.info("removeDeads(): enter");
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309 | synchronized(fileObservers) {
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310 | int deads = 0; |
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311 | for (FileObserver fileObserver : this.fileObservers) { |
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312 | if( fileObserver.isDead() ) {
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313 | deads++; |
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314 | } |
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315 | } |
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316 | if( deads == 0 ) { |
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317 | return;
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318 | } |
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319 | if( deads >= this.fileObservers.size() ) { |
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320 | this.fileObservers.clear();
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321 | return;
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322 | } |
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323 | List<FileObserver> lives = new ArrayList<>(this.fileObservers.size()-deads); |
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324 | for (FileObserver fileObserver : this.fileObservers) { |
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325 | if( fileObserver.isDead() ) {
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326 | if( this.getWatchCounts(fileObserver.getFolder())<1 ) { |
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327 | this.process.cancelWatch(fileObserver.getFolder());
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328 | } |
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329 | } else {
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330 | lives.add(fileObserver); |
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331 | } |
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332 | } |
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333 | this.fileObservers.clear();
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334 | this.fileObservers.addAll(lives);
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335 | } |
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336 | // LOGGER.info("removeDeads(): exit");
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337 | } |
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338 | |||
339 | public void deleteObservers() { |
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340 | // LOGGER.info("deleteObservers(): enter");
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341 | List<FileObserver> x;
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342 | synchronized(fileObservers) {
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343 | x = this.fileObservers;
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344 | this.fileObservers.clear();
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345 | } |
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346 | for (FileObserver fileObserver : x) {
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347 | this.process.cancelWatch(fileObserver.getFolder());
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348 | } |
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349 | // LOGGER.info("deleteObservers(): exit");
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350 | } |
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351 | |||
352 | } |