1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27 package org.apache.http.pool;
28
29 import java.util.concurrent.Future;
30
31 import org.apache.http.concurrent.FutureCallback;
32
33 /**
34 * {@code ConnPool} represents a shared pool connections can be leased from
35 * and released back to.
36 *
37 * @param <T> the route type that represents the opposite endpoint of a pooled
38 * connection.
39 * @param <E> the type of the pool entry containing a pooled connection.
40 * @since 4.2
41 */
42 public interface ConnPool<T, E> {
43
44 /**
45 * Attempts to lease a connection for the given route and with the given
46 * state from the pool.
47 *
48 * @param route route of the connection.
49 * @param state arbitrary object that represents a particular state
50 * (usually a security principal or a unique token identifying
51 * the user whose credentials have been used while establishing the connection).
52 * May be {@code null}.
53 * @param callback operation completion callback.
54 *
55 * @return future for a leased pool entry.
56 */
57 Future<E> lease(final T route, final Object state, final FutureCallback<E> callback);
58
59 /**
60 * Releases the pool entry back to the pool.
61 *
62 * @param entry pool entry leased from the pool
63 * @param reusable flag indicating whether or not the released connection
64 * is in a consistent state and is safe for further use.
65 */
66 void release(E entry, boolean reusable);
67
68 }