1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.mina.transport.socket.apr;
21
22 import org.apache.tomcat.jni.Library;
23 import org.apache.tomcat.jni.Pool;
24
25
26 /**
27 * Internal singleton used for initializing correctly the APR native library
28 * and the associated root memory pool.
29 *
30 * It'll finalize nicely the native resources (libraries and memory pools).
31 *
32 * Each memory pool used in the APR transport module needs to be children of the
33 * root pool {@link AprLibrary#getRootPool()}.
34 *
35 * @author The Apache MINA Project (dev@mina.apache.org)
36 */
37 class AprLibrary {
38
39 // is APR library was initialized (load of native libraries)
40 private static AprLibrary library = null;
41
42 /**
43 * get the shared instance of APR library, if none, initialize one
44 * @return the current APR library singleton
45 */
46 static synchronized AprLibrary getInstance() {
47 if (!isInitialized())
48 initialize();
49 return library;
50 }
51
52 /**
53 * initialize the APR Library by loading the associated native libraries
54 * and creating the associated singleton
55 */
56 private static synchronized void initialize() {
57 if (library == null)
58 library = new AprLibrary();
59 }
60
61 /**
62 * is the APR library was initialized.
63 * @return true if the Library is initialized, false otherwise
64 */
65 static synchronized boolean isInitialized() {
66 return library != null;
67 }
68
69 // APR memory pool (package wide mother pool)
70 private final long pool;
71
72 /**
73 * APR library singleton constructor. Called only when accessing the
74 * singleton the first time.
75 * It's initializing an APR memory pool for the whole package (a.k.a mother or root pool).
76 */
77 private AprLibrary() {
78 try {
79 Library.initialize(null);
80 } catch (Exception e) {
81 throw new RuntimeException(
82 "Error loading Apache Portable Runtime (APR).", e);
83 }
84 pool = Pool.create(0);
85 }
86
87 @Override
88 protected void finalize() throws Throwable {
89 super.finalize();
90 Pool.destroy(pool);
91 }
92
93 /**
94 * get the package wide root pool, the mother of all the pool created
95 * in APR transport module.
96 * @return number identifying the root pool
97 */
98 long getRootPool() {
99 return pool;
100 }
101 }