1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.text.translate;
18
19 import java.io.IOException;
20 import java.io.Writer;
21
22 import org.apache.commons.lang3.CharUtils;
23 import org.apache.commons.lang3.StringUtils;
24
25 /**
26 * This class holds inner classes for escaping/unescaping Comma Separated Values.
27 * <p>
28 * In general the use a high level API like <a href="https://commons.apache.org/proper/commons-csv/">Apache Commons
29 * CSV</a> should be preferred over these low level classes.
30 * </p>
31 *
32 * @see <a href="https://commons.apache.org/proper/commons-csv/apidocs/index.html">Apache Commons CSV</a>
33 */
34 public final class CsvTranslators {
35
36 /**
37 * Translator for escaping Comma Separated Values.
38 */
39 public static class CsvEscaper extends SinglePassTranslator {
40
41 /**
42 * Construct a new instance.
43 */
44 public CsvEscaper() {
45 // empty
46 }
47
48 @Override
49 void translateWhole(final CharSequence input, final Writer writer) throws IOException {
50 final String inputSting = input.toString();
51 if (StringUtils.containsNone(inputSting, CSV_SEARCH_CHARS)) {
52 writer.write(inputSting);
53 } else {
54 // input needs quoting
55 writer.write(CSV_QUOTE);
56 writer.write(StringUtils.replace(inputSting, CSV_QUOTE_STR, CSV_ESCAPED_QUOTE_STR));
57 writer.write(CSV_QUOTE);
58 }
59 }
60 }
61 /**
62 * Translator for unescaping escaped Comma Separated Value entries.
63 */
64 public static class CsvUnescaper extends SinglePassTranslator {
65
66 /**
67 * Construct a new instance.
68 */
69 public CsvUnescaper() {
70 // empty
71 }
72
73 @Override
74 void translateWhole(final CharSequence input, final Writer writer) throws IOException {
75 // is input not quoted?
76 if (input.charAt(0) != CSV_QUOTE || input.charAt(input.length() - 1) != CSV_QUOTE) {
77 writer.write(input.toString());
78 return;
79 }
80
81 // strip quotes
82 final String quoteless = input.subSequence(1, input.length() - 1).toString();
83
84 if (StringUtils.containsAny(quoteless, CSV_SEARCH_CHARS)) {
85 // deal with escaped quotes; ie) ""
86 writer.write(StringUtils.replace(quoteless, CSV_ESCAPED_QUOTE_STR, CSV_QUOTE_STR));
87 } else {
88 writer.write(quoteless);
89 }
90 }
91 }
92 /** Comma character. */
93 private static final char CSV_DELIMITER = ',';
94 /** Quote character. */
95 private static final char CSV_QUOTE = '"';
96 /** Quote character converted to string. */
97 private static final String CSV_QUOTE_STR = String.valueOf(CSV_QUOTE);
98
99 /** Escaped quote string. */
100 private static final String CSV_ESCAPED_QUOTE_STR = CSV_QUOTE_STR + CSV_QUOTE_STR;
101
102 /** CSV key characters in an array. */
103 private static final char[] CSV_SEARCH_CHARS = { CSV_DELIMITER, CSV_QUOTE, CharUtils.CR, CharUtils.LF };
104
105 /** Hidden constructor. */
106 private CsvTranslators() {
107 // empty
108 }
109 }