/*
 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.nio.file;

An event or a repeated event for an object that is registered with a WatchService. 
 An event is classified by its kind and has a count to indicate the number of times that the event has been observed. This allows for efficient representation of repeated events. The context method returns any context associated with the event. In the case of a repeated event then the context is the same for all events. 
 Watch events are immutable and safe for use by multiple concurrent
threads.
Type parameters:
<T> –     The type of the context object associated with the event
Since:
1.7/**
 * An event or a repeated event for an object that is registered with a {@link
 * WatchService}.
 *
 * <p> An event is classified by its {@link #kind() kind} and has a {@link
 * #count() count} to indicate the number of times that the event has been
 * observed. This allows for efficient representation of repeated events. The
 * {@link #context() context} method returns any context associated with
 * the event. In the case of a repeated event then the context is the same for
 * all events.
 *
 * <p> Watch events are immutable and safe for use by multiple concurrent
 * threads.
 *
 * @param   <T>     The type of the context object associated with the event
 *
 * @since 1.7
 */

public interface WatchEvent<T> {

    
An event kind, for the purposes of identification.
See Also:
StandardWatchEventKinds
Since:
1.7/**
     * An event kind, for the purposes of identification.
     *
     * @since 1.7
     * @see StandardWatchEventKinds
     */
    public static interface Kind<T> {
        
Returns the name of the event kind.
Returns:
the name of the event kind/**
         * Returns the name of the event kind.
         *
         * @return the name of the event kind
         */
        String name();

        
Returns the type of the context value. 
Returns:
the type of the context value/**
         * Returns the type of the {@link WatchEvent#context context} value.
         *
         *
         * @return the type of the context value
         */
        Class<T> type();
    }

    
An event modifier that qualifies how a Watchable is registered with a WatchService. 
 This release does not define any standard modifiers.
See Also:
Watchable.register
Since:
1.7/**
     * An event modifier that qualifies how a {@link Watchable} is registered
     * with a {@link WatchService}.
     *
     * <p> This release does not define any <em>standard</em> modifiers.
     *
     * @since 1.7
     * @see Watchable#register
     */
    public static interface Modifier {
        
Returns the name of the modifier.
Returns:
the name of the modifier/**
         * Returns the name of the modifier.
         *
         * @return the name of the modifier
         */
        String name();
    }

    
Returns the event kind.
Returns:
 the event kind/**
     * Returns the event kind.
     *
     * @return  the event kind
     */
    Kind<T> kind();

    
Returns the event count. If the event count is greater than 1 then this is a repeated event. 
Returns:
 the event count/**
     * Returns the event count. If the event count is greater than {@code 1}
     * then this is a repeated event.
     *
     * @return  the event count
     */
    int count();

    
Returns the context for the event.
 In the case of ENTRY_CREATE, ENTRY_DELETE, and ENTRY_MODIFY events the context is a Path that is the relative path between the directory registered with the watch service, and the entry that is created, deleted, or modified. 
Returns:
 the event context; may be null/**
     * Returns the context for the event.
     *
     * <p> In the case of {@link StandardWatchEventKinds#ENTRY_CREATE ENTRY_CREATE},
     * {@link StandardWatchEventKinds#ENTRY_DELETE ENTRY_DELETE}, and {@link
     * StandardWatchEventKinds#ENTRY_MODIFY ENTRY_MODIFY} events the context is
     * a {@code Path} that is the {@link Path#relativize relative} path between
     * the directory registered with the watch service, and the entry that is
     * created, deleted, or modified.
     *
     * @return  the event context; may be {@code null}
     */
    T context();
}