/*

* Copyright (c) 2004-2019 Tada AB and other contributors, as listed below.

*

* All rights reserved. This program and the accompanying materials

* are made available under the terms of the The BSD 3-Clause License

* which accompanies this distribution, and is available at

* http://opensource.org/licenses/BSD-3-Clause

*

* Contributors:

* Tada AB

* Purdue University

*/

package org.postgresql.pljava;

import java.sql.SQLException;

/**

* A pool of objects of a single class.

* Obtain an <code>ObjectPool</code> from the {@link Session} by calling

* {@link Session#getObjectPool getObjectPool} with a {@link Class} object

* for the class to be pooled, which must implement {@link PooledObject}.

* @author Thomas Hallgren

*/

public interface ObjectPool<T extends PooledObject>

{

/**

* Obtain a pooled object, calling its {@link PooledObject#activate()}

* method. A new instance is created if needed. The pooled

* object is removed from the pool and activated.

*

* @return A new object or an object found in the pool.

*/

T activateInstance()

throws SQLException;

/**

* Call the {@link PooledObject#passivate()} method and return the object

* to the pool.

* @param instance The instance to passivate.

*/

void passivateInstance(T instance)

throws SQLException;

/**

* Call the {@link PooledObject#remove()} method and evict the object

* from the pool.

*/

void removeInstance(T instance)

throws SQLException;

}