Tomcat example source code file (Library.java)

This example Tomcat source code file (Library.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

apr_has_fork, apr_has_threads, apr_has_threads, apr_has_user, apr_is_dev_version, apr_major_version, apr_major_version, apr_o_nonblock_inherited, library, library, string, string, tcn_minor_version, unsatisfiedlinkerror

The Tomcat Library.java source code

/*
 *  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.tomcat.jni;

/** Library
 *
 * @author Mladen Turk
 * @version $Revision: 467222 $, $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */

public final class Library {

    /* Default library names */
    private static String [] NAMES = {"tcnative-1", "libtcnative-1"};
    /*
     * A handle to the unique Library singleton instance.
     */
    static private Library _instance = null;

    private Library()
    {
        boolean loaded = false;
        String err = "";
        for (int i = 0; i < NAMES.length; i++) {
            try {
                System.loadLibrary(NAMES[i]);
                loaded = true;
            }
            catch (Throwable e) {
                if ( i > 0)
                    err += ", ";
                err +=  e.getMessage();
            }
            if (loaded)
                break;
        }
        if (!loaded) {
            err += "(";
            err += System.getProperty("java.library.path");
            err += ")";
            throw new UnsatisfiedLinkError(err);
        }
    }

    private Library(String libraryName)
    {
        System.loadLibrary(libraryName);
    }

    /* create global TCN's APR pool
     * This has to be the first call to TCN library.
     */
    private static native boolean initialize();
    /* destroy global TCN's APR pool
     * This has to be the last call to TCN library.
     */
    public static native void terminate();
    /* Internal function for loading APR Features */
    private static native boolean has(int what);
    /* Internal function for loading APR Features */
    private static native int version(int what);
    /* Internal function for loading APR sizes */
    private static native int size(int what);

    /* TCN_MAJOR_VERSION */
    public static int TCN_MAJOR_VERSION  = 0;
    /* TCN_MINOR_VERSION */
    public static int TCN_MINOR_VERSION  = 0;
    /* TCN_PATCH_VERSION */
    public static int TCN_PATCH_VERSION  = 0;
    /* TCN_IS_DEV_VERSION */
    public static int TCN_IS_DEV_VERSION = 0;
    /* APR_MAJOR_VERSION */
    public static int APR_MAJOR_VERSION  = 0;
    /* APR_MINOR_VERSION */
    public static int APR_MINOR_VERSION  = 0;
    /* APR_PATCH_VERSION */
    public static int APR_PATCH_VERSION  = 0;
    /* APR_IS_DEV_VERSION */
    public static int APR_IS_DEV_VERSION = 0;

    /* TCN_VERSION_STRING */
    public static native String versionString();
    /* APR_VERSION_STRING */
    public static native String aprVersionString();

    /*  APR Feature Macros */
    public static boolean APR_HAVE_IPV6           = false;
    public static boolean APR_HAS_SHARED_MEMORY   = false;
    public static boolean APR_HAS_THREADS         = false;
    public static boolean APR_HAS_SENDFILE        = false;
    public static boolean APR_HAS_MMAP            = false;
    public static boolean APR_HAS_FORK            = false;
    public static boolean APR_HAS_RANDOM          = false;
    public static boolean APR_HAS_OTHER_CHILD     = false;
    public static boolean APR_HAS_DSO             = false;
    public static boolean APR_HAS_SO_ACCEPTFILTER = false;
    public static boolean APR_HAS_UNICODE_FS      = false;
    public static boolean APR_HAS_PROC_INVOKED    = false;
    public static boolean APR_HAS_USER            = false;
    public static boolean APR_HAS_LARGE_FILES     = false;
    public static boolean APR_HAS_XTHREAD_FILES   = false;
    public static boolean APR_HAS_OS_UUID         = false;
    /* Are we big endian? */
    public static boolean APR_IS_BIGENDIAN        = false;
    /* APR sets APR_FILES_AS_SOCKETS to 1 on systems where it is possible
     * to poll on files/pipes.
     */
    public static boolean APR_FILES_AS_SOCKETS    = false;
    /* This macro indicates whether or not EBCDIC is the native character set.
     */
    public static boolean APR_CHARSET_EBCDIC      = false;
    /* Is the TCP_NODELAY socket option inherited from listening sockets?
     */
    public static boolean APR_TCP_NODELAY_INHERITED = false;
    /* Is the O_NONBLOCK flag inherited from listening sockets?
     */
    public static boolean APR_O_NONBLOCK_INHERITED  = false;


    public static int APR_SIZEOF_VOIDP;
    public static int APR_PATH_MAX;
    public static int APRMAXHOSTLEN;
    public static int APR_MAX_IOVEC_SIZE;
    public static int APR_MAX_SECS_TO_LINGER;
    public static int APR_MMAP_THRESHOLD;
    public static int APR_MMAP_LIMIT;

    /* return global TCN's APR pool */
    public static native long globalPool();

    /**
     * Setup any APR internal data structures.  This MUST be the first function
     * called for any APR library.
     * @param libraryName the name of the library to load
     */
    static public boolean initialize(String libraryName)
        throws Exception
    {
        if (_instance == null) {
            if (libraryName == null)
                _instance = new Library();
            else
                _instance = new Library(libraryName);
            TCN_MAJOR_VERSION  = version(0x01);
            TCN_MINOR_VERSION  = version(0x02);
            TCN_PATCH_VERSION  = version(0x03);
            TCN_IS_DEV_VERSION = version(0x04);
            APR_MAJOR_VERSION  = version(0x11);
            APR_MINOR_VERSION  = version(0x12);
            APR_PATCH_VERSION  = version(0x13);
            APR_IS_DEV_VERSION = version(0x14);

            APR_SIZEOF_VOIDP        = size(1);
            APR_PATH_MAX            = size(2);
            APRMAXHOSTLEN           = size(3);
            APR_MAX_IOVEC_SIZE      = size(4);
            APR_MAX_SECS_TO_LINGER  = size(5);
            APR_MMAP_THRESHOLD      = size(6);
            APR_MMAP_LIMIT          = size(7);

            APR_HAVE_IPV6           = has(0);
            APR_HAS_SHARED_MEMORY   = has(1);
            APR_HAS_THREADS         = has(2);
            APR_HAS_SENDFILE        = has(3);
            APR_HAS_MMAP            = has(4);
            APR_HAS_FORK            = has(5);
            APR_HAS_RANDOM          = has(6);
            APR_HAS_OTHER_CHILD     = has(7);
            APR_HAS_DSO             = has(8);
            APR_HAS_SO_ACCEPTFILTER = has(9);
            APR_HAS_UNICODE_FS      = has(10);
            APR_HAS_PROC_INVOKED    = has(11);
            APR_HAS_USER            = has(12);
            APR_HAS_LARGE_FILES     = has(13);
            APR_HAS_XTHREAD_FILES   = has(14);
            APR_HAS_OS_UUID         = has(15);
            APR_IS_BIGENDIAN        = has(16);
            APR_FILES_AS_SOCKETS    = has(17);
            APR_CHARSET_EBCDIC      = has(18);
            APR_TCP_NODELAY_INHERITED = has(19);
            APR_O_NONBLOCK_INHERITED  = has(20);
            if (APR_MAJOR_VERSION < 1) {
                throw new UnsatisfiedLinkError("Unsupported APR Version (" +
                                               aprVersionString() + ")");
            }
            if (!APR_HAS_THREADS) {
                throw new UnsatisfiedLinkError("Missing APR_HAS_THREADS");
            }
        }
        return initialize();
    }
}