| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.solr.internal.csv; |
| |
| import java.io.StringWriter; |
| import java.io.StringReader; |
| import java.io.IOException; |
| |
| /** |
| * Utility methods for dealing with CSV files |
| */ |
| public class CSVUtils { |
| |
| private static final String[] EMPTY_STRING_ARRAY = new String[0]; |
| private static final String[][] EMPTY_DOUBLE_STRING_ARRAY = new String[0][0]; |
| |
| /** |
| * <p><code>CSVUtils</code> instances should NOT be constructed in |
| * standard programming. |
| * |
| * <p>This constructor is public to permit tools that require a JavaBean |
| * instance to operate.</p> |
| */ |
| public CSVUtils() { |
| } |
| |
| /** |
| * Converts an array of string values into a single CSV line. All |
| * <code>null</code> values are converted to the string <code>"null"</code>, |
| * all strings equal to <code>"null"</code> will additionally get quotes |
| * around. |
| * |
| * @param values the value array |
| * @return the CSV string, will be an empty string if the length of the |
| * value array is 0 |
| */ |
| public static String printLine(String[] values, CSVStrategy strategy) { |
| // set up a CSVUtils |
| StringWriter stringWriter = new StringWriter(); |
| CSVPrinter csvPrinter = new CSVPrinter(stringWriter, strategy); |
| |
| // check for null values an "null" as strings and convert them |
| // into the strings "null" and "\"null\"" |
| for (int i = 0; i < values.length; i++) { |
| if (values[i] == null) { |
| values[i] = "null"; |
| } else if (values[i].equals("null")) { |
| values[i] = "\"null\""; |
| } |
| } |
| |
| // convert to CSV |
| try { |
| csvPrinter.println(values); |
| } catch (IOException e) { |
| // should not happen with StringWriter |
| } |
| // as the resulting string has \r\n at the end, we will trim that away |
| return stringWriter.toString().trim(); |
| } |
| |
| // ====================================================== |
| // static parsers |
| // ====================================================== |
| |
| /** |
| * Parses the given String according to the default {@link CSVStrategy}. |
| * |
| * @param s CSV String to be parsed. |
| * @return parsed String matrix (which is never null) |
| * @throws IOException in case of error |
| */ |
| public static String[][] parse(String s) throws IOException { |
| if (s == null) { |
| throw new IllegalArgumentException("Null argument not allowed."); |
| } |
| String[][] result = (new CSVParser(new StringReader(s))).getAllValues(); |
| if (result == null) { |
| // since CSVStrategy ignores empty lines an empty array is returned |
| // (i.e. not "result = new String[][] {{""}};") |
| result = EMPTY_DOUBLE_STRING_ARRAY; |
| } |
| return result; |
| } |
| |
| /** |
| * Parses the first line only according to the default {@link CSVStrategy}. |
| * |
| * Parsing empty string will be handled as valid records containing zero |
| * elements, so the following property holds: parseLine("").length == 0. |
| * |
| * @param s CSV String to be parsed. |
| * @return parsed String vector (which is never null) |
| * @throws IOException in case of error |
| */ |
| public static String[] parseLine(String s) throws IOException { |
| if (s == null) { |
| throw new IllegalArgumentException("Null argument not allowed."); |
| } |
| // uh,jh: make sure that parseLine("").length == 0 |
| if (s.length() == 0) { |
| return EMPTY_STRING_ARRAY; |
| } |
| return (new CSVParser(new StringReader(s))).getLine(); |
| } |
| |
| } |