/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.resource;
import java.io.Closeable;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* Interface representing a pool of resources to be temporarily used and returned.
*
* @param <T> the type of resource this pool manages
*/
public interface Pool<T> extends Closeable {
/**
* Acquires a resource from the pool.
*
* @return the acquired resource which should not be null
*/
T acquire() throws IOException;
/**
* Acquires a resource from the pool.
*
* @param time time it takes before timeout if no resource is available
* @param unit the unit of the time
* @return the acquired resource which should not be null
*/
T acquire(long time, TimeUnit unit) throws TimeoutException, IOException;
/**
* Releases the resource to the pool.
*
* @param resource the resource to release
*/
void release(T resource);
/**
* @return the current pool size
*/
int size();
}