/*
* 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 specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.concurrent;
/**
* <p>
* Definition of an interface for the thread-safe initialization of objects.
* </p>
* <p>
* The idea behind this interface is to provide access to an object in a
* thread-safe manner. A {@code ConcurrentInitializer} can be passed to multiple
* threads which can all access the object produced by the initializer. Through
* the {@link #get()} method the object can be queried.
* </p>
* <p>
* Concrete implementations of this interface will use different strategies for
* the creation of the managed object, e.g. lazy initialization or
* initialization in a background thread. This is completely transparent to
* client code, so it is possible to change the initialization strategy without
* affecting clients.
* </p>
*
* @since 3.0
* @version $Id: ConcurrentInitializer.java 1088899 2011-04-05 05:31:27Z bayard $
* @param <T> the type of the object managed by this initializer class
*/
public interface ConcurrentInitializer<T> {
/**
* Returns the fully initialized object produced by this {@code
* ConcurrentInitializer}. A concrete implementation here returns the
* results of the initialization process. This method may block until
* results are available. Typically, once created the result object is
* always the same.
*
* @return the object created by this {@code ConcurrentException}
* @throws ConcurrentException if an error occurred during initialization of
* the object
*/
T get() throws ConcurrentException;
}
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