java.nio.file.Watchable Maven / Gradle / Ivy
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/*
* Copyright (c) 2007, 2011, 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.
*
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package java.nio.file;
import java.io.IOException;
/**
* An object that may be registered with a watch service so that it can be
* watched for changes and events.
*
* This interface defines the {@link #register register} method to register
* the object with a {@link WatchService} returning a {@link WatchKey} to
* represent the registration. An object may be registered with more than one
* watch service. Registration with a watch service is cancelled by invoking the
* key's {@link WatchKey#cancel cancel} method.
*
* @since 1.7
*
* @see Path#register
*/
public interface Watchable {
/**
* Registers an object with a watch service.
*
*
If the file system object identified by this object is currently
* registered with the watch service then the watch key, representing that
* registration, is returned after changing the event set or modifiers to
* those specified by the {@code events} and {@code modifiers} parameters.
* Changing the event set does not cause pending events for the object to be
* discarded. Objects are automatically registered for the {@link
* StandardWatchEventKinds#OVERFLOW OVERFLOW} event. This event is not
* required to be present in the array of events.
*
*
Otherwise the file system object has not yet been registered with the
* given watch service, so it is registered and the resulting new key is
* returned.
*
*
Implementations of this interface should specify the events they
* support.
*
* @param watcher
* the watch service to which this object is to be registered
* @param events
* the events for which this object should be registered
* @param modifiers
* the modifiers, if any, that modify how the object is registered
*
* @return a key representing the registration of this object with the
* given watch service
*
* @throws UnsupportedOperationException
* if unsupported events or modifiers are specified
* @throws IllegalArgumentException
* if an invalid of combination of events are modifiers are specified
* @throws ClosedWatchServiceException
* if the watch service is closed
* @throws IOException
* if an I/O error occurs
* @throws SecurityException
* if a security manager is installed and it denies an unspecified
* permission required to monitor this object. Implementations of
* this interface should specify the permission checks.
*/
WatchKey register(WatchService watcher,
WatchEvent.Kind[] events,
WatchEvent.Modifier... modifiers)
throws IOException;
/**
* Registers an object with a watch service.
*
*
An invocation of this method behaves in exactly the same way as the
* invocation
*
* watchable.{@link #register(WatchService,WatchEvent.Kind[],WatchEvent.Modifier[]) register}(watcher, events, new WatchEvent.Modifier[0]);
*
*
* @param watcher
* the watch service to which this object is to be registered
* @param events
* the events for which this object should be registered
*
* @return a key representing the registration of this object with the
* given watch service
*
* @throws UnsupportedOperationException
* if unsupported events are specified
* @throws IllegalArgumentException
* if an invalid of combination of events are specified
* @throws ClosedWatchServiceException
* if the watch service is closed
* @throws IOException
* if an I/O error occurs
* @throws SecurityException
* if a security manager is installed and it denies an unspecified
* permission required to monitor this object. Implementations of
* this interface should specify the permission checks.
*/
WatchKey register(WatchService watcher, WatchEvent.Kind... events)
throws IOException;
}