//
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
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// under the License.
//
package com.cloud.utils.component;
import java.util.List;
/**
* Simple interface to represents a registry of items
*
* @param <T>
*/
public interface Registry<T> extends Named {
/**
* Registers an item. If the item has already been registered the implementation
* should detect that it is registered and not re-register it.
*
* @param type
* @return true if register, false if not registered or already exists
*/
boolean register(T type);
void unregister(T type);
/**
* Returns a list that will dynamically change as items are registered/unregister.
* The list is thread safe to iterate upon. Traversing the list using an index
* would not be safe as the size may changed during traversal.
*
* @return Unmodifiable list of registered items
*/
List<T> getRegistered();
}