Java Encode encodeParameter(String name, String value, String encoding, String lang)

Description

encode Parameter

License

Open Source License

Declaration

public static String encodeParameter(String name, String value, String encoding, String lang) 

Method Source Code

//package com.java2s;
/*/*w  ww .  j  a  v  a 2  s.  c o  m*/
 * imoten - i mode.net mail tensou(forward)
 *
 * Copyright (C) 2010 shoozhoo (http://code.google.com/p/imoten/)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 */

import java.io.UnsupportedEncodingException;

import javax.mail.internet.HeaderTokenizer;

import javax.mail.internet.MimeUtility;

public class Main {
    public static String encodeParameter(String name, String value, String encoding, String lang) {
        StringBuffer result = new StringBuffer();
        StringBuffer encodedPart = new StringBuffer();

        boolean needWriteCES = !isAllAscii(value);
        boolean CESWasWritten = false;
        boolean encoded;
        boolean needFolding = false;
        int sequenceNo = 0;
        int column;

        while (value.length() > 0) {
            // index of boundary of ascii/non ascii
            int lastIndex;
            boolean isAscii = value.charAt(0) < 0x80;
            for (lastIndex = 1; lastIndex < value.length(); lastIndex++) {
                if (value.charAt(lastIndex) < 0x80) {
                    if (!isAscii)
                        break;
                } else {
                    if (isAscii)
                        break;
                }
            }
            if (lastIndex != value.length())
                needFolding = true;

            RETRY: while (true) {
                encodedPart.delete(0, encodedPart.length());
                String target = value.substring(0, lastIndex);

                byte[] bytes;
                try {
                    if (isAscii) {
                        bytes = target.getBytes("us-ascii");
                    } else {
                        bytes = target.getBytes(encoding);
                    }
                } catch (UnsupportedEncodingException e) {
                    bytes = target.getBytes(); // use default encoding
                    encoding = MimeUtility.mimeCharset(MimeUtility.getDefaultJavaCharset());
                }

                encoded = false;
                // It is not strict.
                column = name.length() + 7; // size of " " and "*nn*=" and ";"

                for (int i = 0; i < bytes.length; i++) {
                    if (bytes[i] > ' ' && bytes[i] < 'z' && HeaderTokenizer.MIME.indexOf((char) bytes[i]) < 0) {
                        encodedPart.append((char) bytes[i]);
                        column++;
                    } else {
                        encoded = true;
                        encodedPart.append('%');
                        String hex = Integer.toString(bytes[i] & 0xff, 16);
                        if (hex.length() == 1) {
                            encodedPart.append('0');
                        }
                        encodedPart.append(hex);
                        column += 3;
                    }
                    if (column > 76) {
                        needFolding = true;
                        lastIndex /= 2;
                        continue RETRY;
                    }
                }

                result.append(";\r\n ").append(name);
                if (needFolding) {
                    result.append('*').append(sequenceNo);
                    sequenceNo++;
                }
                if (!CESWasWritten && needWriteCES) {
                    result.append("*=");
                    CESWasWritten = true;
                    result.append(encoding).append('\'');
                    if (lang != null)
                        result.append(lang);
                    result.append('\'');
                } else if (encoded) {
                    result.append("*=");
                } else {
                    result.append('=');
                }
                result.append(new String(encodedPart));
                value = value.substring(lastIndex);
                break;
            }
        }
        return new String(result);
    }

    /** check if contains only ascii characters in text. */
    public static boolean isAllAscii(String text) {
        for (int i = 0; i < text.length(); i++) {
            if (text.charAt(i) > 0x7f) { // non-ascii
                return false;
            }
        }
        return true;
    }
}

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