/*
* Syncany, www.syncany.org
* Copyright (C) 2011-2015 Philipp C. Heckel <philipp.heckel@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.syncany.plugins.transfer.features;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.syncany.plugins.transfer.TransferManager;
import org.syncany.plugins.transfer.TransferManagerFactory;
/**
* Annotation to identify and configure {@link TransferManager} extensions.
*
* <p>Features are extensions for transfer managers, such as path awareness,
* transaction awareness or retriability. This annotation is used to mark
* a feature annotation, which in turn corresponds to a {@link FeatureTransferManager}.
*
* <p><b>Note</b>: This annotation must only be used to annotate feature
* annotations, i.e. it is an annotation annotation. It must not be used to
* mark feature transfer managers directly.
*
* @see TransferManager
* @see TransferManagerFactory
* @see FeatureTransferManager
* @author Philipp C. Heckel <philipp.heckel@gmail.com>
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface Feature {
/**
* Specifies whether or not a feature is required.
*
* <p>If a feature is required, but the concrete feature annotation
* is not present at the original transfer manager, the {@link TransferManagerFactory}
* will throw an exception.
*/
boolean required();
}