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25 
26 package java.nio.file;
27 
28 /**
29  * Defines the <em>standard</em> event kinds.
30  *
31  * @since 1.7
32  */
33 
34 public final class StandardWatchEventKinds {
StandardWatchEventKinds()35     private StandardWatchEventKinds() { }
36 
37     /**
38      * A special event to indicate that events may have been lost or
39      * discarded.
40      *
41      * <p> The {@link WatchEvent#context context} for this event is
42      * implementation specific and may be {@code null}. The event {@link
43      * WatchEvent#count count} may be greater than {@code 1}.
44      *
45      * @see WatchService
46      */
47     public static final WatchEvent.Kind<Object> OVERFLOW =
48         new StdWatchEventKind<Object>("OVERFLOW", Object.class);
49 
50     /**
51      * Directory entry created.
52      *
53      * <p> When a directory is registered for this event then the {@link WatchKey}
54      * is queued when it is observed that an entry is created in the directory
55      * or renamed into the directory. The event {@link WatchEvent#count count}
56      * for this event is always {@code 1}.
57      */
58     public static final WatchEvent.Kind<Path> ENTRY_CREATE =
59         new StdWatchEventKind<Path>("ENTRY_CREATE", Path.class);
60 
61     /**
62      * Directory entry deleted.
63      *
64      * <p> When a directory is registered for this event then the {@link WatchKey}
65      * is queued when it is observed that an entry is deleted or renamed out of
66      * the directory. The event {@link WatchEvent#count count} for this event
67      * is always {@code 1}.
68      */
69     public static final WatchEvent.Kind<Path> ENTRY_DELETE =
70         new StdWatchEventKind<Path>("ENTRY_DELETE", Path.class);
71 
72     /**
73      * Directory entry modified.
74      *
75      * <p> When a directory is registered for this event then the {@link WatchKey}
76      * is queued when it is observed that an entry in the directory has been
77      * modified. The event {@link WatchEvent#count count} for this event is
78      * {@code 1} or greater.
79      */
80     public static final WatchEvent.Kind<Path> ENTRY_MODIFY =
81         new StdWatchEventKind<Path>("ENTRY_MODIFY", Path.class);
82 
83     private static class StdWatchEventKind<T> implements WatchEvent.Kind<T> {
84         private final String name;
85         private final Class<T> type;
StdWatchEventKind(String name, Class<T> type)86         StdWatchEventKind(String name, Class<T> type) {
87             this.name = name;
88             this.type = type;
89         }
name()90         @Override public String name() { return name; }
type()91         @Override public Class<T> type() { return type; }
toString()92         @Override public String toString() { return name; }
93     }
94 }
95