1 /* 2 * Copyright 2001-2004 The Apache Software Foundation. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.apache.commons.codec.net; 18 19 import java.io.UnsupportedEncodingException; 20 21 import org.apache.commons.codec.DecoderException; 22 import org.apache.commons.codec.EncoderException; 23 24 /** 25 * <p> 26 * Implements methods common to all codecs defined in RFC 1522. 27 * </p> 28 * 29 * <p> 30 * <a href="http://www.ietf.org/rfc/rfc1522.txt">RFC 1522</a> 31 * describes techniques to allow the encoding of non-ASCII text in 32 * various portions of a RFC 822 [2] message header, in a manner which 33 * is unlikely to confuse existing message handling software. 34 * </p> 35 36 * @see <a href="http://www.ietf.org/rfc/rfc1522.txt"> 37 * MIME (Multipurpose Internet Mail Extensions) Part Two: 38 * Message Header Extensions for Non-ASCII Text</a> 39 * </p> 40 * 41 * @author Apache Software Foundation 42 * @since 1.3 43 * @version $Id: RFC1522Codec.java,v 1.2 2004/04/09 22:21:43 ggregory Exp $ 44 * 45 * @deprecated Please use {@link java.net.URL#openConnection} instead. 46 * Please visit <a href="http://android-developers.blogspot.com/2011/09/androids-http-clients.html">this webpage</a> 47 * for further details. 48 */ 49 @Deprecated 50 abstract class RFC1522Codec { 51 52 /** 53 * Applies an RFC 1522 compliant encoding scheme to the given string of text with the 54 * given charset. This method constructs the "encoded-word" header common to all the 55 * RFC 1522 codecs and then invokes {@link #doEncoding(byte [])} method of a concrete 56 * class to perform the specific enconding. 57 * 58 * @param text a string to encode 59 * @param charset a charset to be used 60 * 61 * @return RFC 1522 compliant "encoded-word" 62 * 63 * @throws EncoderException thrown if there is an error conidition during the Encoding 64 * process. 65 * @throws UnsupportedEncodingException thrown if charset is not supported 66 * 67 * @see <a href="http://java.sun.com/j2se/1.3/docs/api/java/lang/package-summary.html#charenc">JRE character 68 * encoding names</a> 69 */ encodeText(final String text, final String charset)70 protected String encodeText(final String text, final String charset) 71 throws EncoderException, UnsupportedEncodingException 72 { 73 if (text == null) { 74 return null; 75 } 76 StringBuffer buffer = new StringBuffer(); 77 buffer.append("=?"); 78 buffer.append(charset); 79 buffer.append('?'); 80 buffer.append(getEncoding()); 81 buffer.append('?'); 82 byte [] rawdata = doEncoding(text.getBytes(charset)); 83 buffer.append(new String(rawdata, StringEncodings.US_ASCII)); 84 buffer.append("?="); 85 return buffer.toString(); 86 } 87 88 /** 89 * Applies an RFC 1522 compliant decoding scheme to the given string of text. This method 90 * processes the "encoded-word" header common to all the RFC 1522 codecs and then invokes 91 * {@link #doEncoding(byte [])} method of a concrete class to perform the specific deconding. 92 * 93 * @param text a string to decode 94 * 95 * @throws DecoderException thrown if there is an error conidition during the Decoding 96 * process. 97 * @throws UnsupportedEncodingException thrown if charset specified in the "encoded-word" 98 * header is not supported 99 */ decodeText(final String text)100 protected String decodeText(final String text) 101 throws DecoderException, UnsupportedEncodingException 102 { 103 if (text == null) { 104 return null; 105 } 106 if ((!text.startsWith("=?")) || (!text.endsWith("?="))) { 107 throw new DecoderException("RFC 1522 violation: malformed encoded content"); 108 } 109 int termnator = text.length() - 2; 110 int from = 2; 111 int to = text.indexOf("?", from); 112 if ((to == -1) || (to == termnator)) { 113 throw new DecoderException("RFC 1522 violation: charset token not found"); 114 } 115 String charset = text.substring(from, to); 116 if (charset.equals("")) { 117 throw new DecoderException("RFC 1522 violation: charset not specified"); 118 } 119 from = to + 1; 120 to = text.indexOf("?", from); 121 if ((to == -1) || (to == termnator)) { 122 throw new DecoderException("RFC 1522 violation: encoding token not found"); 123 } 124 String encoding = text.substring(from, to); 125 if (!getEncoding().equalsIgnoreCase(encoding)) { 126 throw new DecoderException("This codec cannot decode " + 127 encoding + " encoded content"); 128 } 129 from = to + 1; 130 to = text.indexOf("?", from); 131 byte[] data = text.substring(from, to).getBytes(StringEncodings.US_ASCII); 132 data = doDecoding(data); 133 return new String(data, charset); 134 } 135 136 /** 137 * Returns the codec name (referred to as encoding in the RFC 1522) 138 * 139 * @return name of the codec 140 */ getEncoding()141 protected abstract String getEncoding(); 142 143 /** 144 * Encodes an array of bytes using the defined encoding scheme 145 * 146 * @param bytes Data to be encoded 147 * 148 * @return A byte array containing the encoded data 149 * 150 * @throws EncoderException thrown if the Encoder encounters a failure condition 151 * during the encoding process. 152 */ doEncoding(byte[] bytes)153 protected abstract byte[] doEncoding(byte[] bytes) throws EncoderException; 154 155 /** 156 * Decodes an array of bytes using the defined encoding scheme 157 * 158 * @param bytes Data to be decoded 159 * 160 * @return a byte array that contains decoded data 161 * 162 * @throws DecoderException A decoder exception is thrown if a Decoder encounters a 163 * failure condition during the decode process. 164 */ doDecoding(byte[] bytes)165 protected abstract byte[] doDecoding(byte[] bytes) throws DecoderException; 166 } 167