conv.java

有关j2me的很好的例子可以研究一下

/*
 * @(#)Conv.java	1.6 01/08/21
 * Copyright (c) 1999-2001 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Sun.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 */

package com.sun.cldc.i18n.j2me;
/** 
 * Character conversion base class
 */
class Conv {
    /**
     * Native method to get a handle to specific character 
     * encoding convesrion routine.
     *
     * @param encoding character encoding
     * @return identifier for requested handler, or zero if
     * the encoding was not supported.
     */
    native static int getHandler(String encoding);

    /**
     * Native function to set the maximum length in bytes 
     * for a converted string.
     *
     * @param handler handle returned from getHandler
     * @return maximum byte length, or zero if handler
     * is not valid
     * @see #getHandler
     */
    native static int getMaxByteLength(int handler);

    /**
     * Get the length of a specific converted string.
     *
     * @param handler handle returned from getHandler
     * @param b buffer of bytes to be converted
     * @param offset offset into the provided buffer
     * @param len length of data to be processed
     * @return length of the converted string, or zero
     * if arguments were not valid
     * @see #getHandler
     */
    native static int getByteLength(int handler, 
                                    byte[] b, int offset, int len);

    /**
     * Native function to convert an array of bytes to 
     * converted array of characters.
     *
     * @param handler handle returned from getHandler
     * @param input buffer of bytes to be converted
     * @param in_offset offset into the provided buffer
     * @param in_len length of data to be processed
     * @param output buffer of converted bytes
     * @param out_offset offset into the provided output buffer
     * @param out_len length of data processed
     * @return length of the converted string, or zero if
     * the arguments were not valid
     * @see #getHandler
     */
    native static int byteToChar(int handler, 
                                 byte[] input,  int in_offset,  int in_len,
                                 char[] output, int out_offset, int out_len);
    /**
     * Native function to convert an array of characters
     * to an array of converted characters.
     *
     * @param handler handle returned from getHandler
     * @param input buffer of bytes to be converted
     * @param in_offset offset into the provided buffer
     * @param in_len length of data to be processed
     * @param output buffer of converted bytes
     * @param out_offset offset into the provided output buffer
     * @param out_len length of data processed
     * @return length of the converted string, or zero if 
     * the arguments were not valid
     * @see #getHandler
     */
    native static int charToByte(int handler, 
                                 char[] input,  int in_offset,  int in_len,
                                 byte[] output, int out_offset, int out_len);
    /**
     * Native function to get the length of a specific 
     * converted string as an array of Unicode bytes.
     *
     * @param handler handle returned from getHandler
     * @param b buffer of bytes to be converted
     * @param offset offset into the provided buffer
     * @param length length of data to be processed
     * @return length of the converted string, or zero
     * if the arguments were not valid
     * @see #getHandler
     */
    native static int sizeOfByteInUnicode(int handler,
                                          byte[] b, int offset, int length);
    /**
     * Native function to get the length of a specific 
     * converted string as an array of Unicode characters.
     *
     * @param handler handle returned from getHandler
     * @param c buffer of characters to be converted
     * @param offset offset into the provided buffer
     * @param length length of data to be processed
     * @return length of the converted string, or zero
     * if the arguments were not valid
     * @see #getHandler
     */
    native static int sizeOfUnicodeInByte(int handler,
                                          char[] c, int offset, int length);
    // debug method
    // native static void println(int handler, String str);
}