001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.text.translate; 018 019import java.io.IOException; 020import java.io.Writer; 021 022import org.apache.commons.lang3.CharUtils; 023import org.apache.commons.lang3.StringUtils; 024 025/** 026 * This class holds inner classes for escaping/unescaping Comma Separated Values. 027 * <p> 028 * In general the use a high level API like <a href="http://commons.apache.org/proper/commons-csv/">Apache Commons 029 * CSV</a> should be preferred over these low level classes. 030 * </p> 031 * 032 * @see <a href="http://commons.apache.org/proper/commons-csv/apidocs/index.html">Apache Commons CSV</a> 033 */ 034public final class CsvTranslators { 035 036 /** Comma character. */ 037 private static final char CSV_DELIMITER = ','; 038 /** Quote character. */ 039 private static final char CSV_QUOTE = '"'; 040 /** Quote character converted to string. */ 041 private static final String CSV_QUOTE_STR = String.valueOf(CSV_QUOTE); 042 /** Escaped quote string. */ 043 private static final String CSV_ESCAPED_QUOTE_STR = CSV_QUOTE_STR + CSV_QUOTE_STR; 044 /** CSV key characters in an array. */ 045 private static final char[] CSV_SEARCH_CHARS = 046 new char[] {CSV_DELIMITER, CSV_QUOTE, CharUtils.CR, CharUtils.LF}; 047 048 /** Hidden constructor. */ 049 private CsvTranslators() { } 050 051 /** 052 * Translator for escaping Comma Separated Values. 053 */ 054 public static class CsvEscaper extends SinglePassTranslator { 055 056 @Override 057 void translateWhole(final CharSequence input, final Writer out) throws IOException { 058 final String inputSting = input.toString(); 059 if (StringUtils.containsNone(inputSting, CSV_SEARCH_CHARS)) { 060 out.write(inputSting); 061 } else { 062 // input needs quoting 063 out.write(CSV_QUOTE); 064 out.write(StringUtils.replace(inputSting, CSV_QUOTE_STR, CSV_ESCAPED_QUOTE_STR)); 065 out.write(CSV_QUOTE); 066 } 067 } 068 } 069 070 /** 071 * Translator for unescaping escaped Comma Separated Value entries. 072 */ 073 public static class CsvUnescaper extends SinglePassTranslator { 074 075 @Override 076 void translateWhole(final CharSequence input, final Writer out) throws IOException { 077 // is input not quoted? 078 if (input.charAt(0) != CSV_QUOTE || input.charAt(input.length() - 1) != CSV_QUOTE) { 079 out.write(input.toString()); 080 return; 081 } 082 083 // strip quotes 084 final String quoteless = input.subSequence(1, input.length() - 1).toString(); 085 086 if (StringUtils.containsAny(quoteless, CSV_SEARCH_CHARS)) { 087 // deal with escaped quotes; ie) "" 088 out.write(StringUtils.replace(quoteless, CSV_ESCAPED_QUOTE_STR, CSV_QUOTE_STR)); 089 } else { 090 out.write(input.toString()); 091 } 092 } 093 } 094}