org.argeo.util/src/org/argeo/util/CsvWriter.java

   1 package org.argeo.util;
   2
   3 import java.io.IOException;
   4 import java.io.OutputStream;
   5 import java.io.OutputStreamWriter;
   6 import java.io.UnsupportedEncodingException;
   7 import java.io.Writer;
   8 import java.util.Iterator;
   9 import java.util.List;
  10
  11 /** Write in CSV format. */
  12 public class CsvWriter {
  13         private final Writer out;
  14
  15         private char separator = ',';
  16         private char quote = '\"';
  17
  18         /**
  19          * Creates a CSV writer.
  20          *
  21          * @param out
  22          *            the stream to write to. Caller is responsible for closing it.
  23          */
  24         public CsvWriter(OutputStream out) {
  25                 this.out = new OutputStreamWriter(out);
  26         }
  27
  28         /**
  29          * Creates a CSV writer.
  30          *
  31          * @param out
  32          *            the stream to write to. Caller is responsible for closing it.
  33          */
  34         public CsvWriter(OutputStream out, String encoding) {
  35                 try {
  36                         this.out = new OutputStreamWriter(out, encoding);
  37                 } catch (UnsupportedEncodingException e) {
  38                         throw new UtilsException("Cannot initialize CSV writer", e);
  39                 }
  40         }
  41
  42         /**
  43          * Write a CSV line. Also used to write a header if needed (this is
  44          * transparent for the CSV writer): simply call it first, before writing the
  45          * lines.
  46          */
  47         public void writeLine(List<?> tokens) {
  48                 try {
  49                         Iterator<?> it = tokens.iterator();
  50                         while (it.hasNext()) {
  51                                 writeToken(it.next().toString());
  52                                 if (it.hasNext())
  53                                         out.write(separator);
  54                         }
  55                         out.write('\n');
  56                         out.flush();
  57                 } catch (IOException e) {
  58                         throw new UtilsException("Could not write " + tokens, e);
  59                 }
  60         }
  61
  62         /**
  63          * Write a CSV line. Also used to write a header if needed (this is
  64          * transparent for the CSV writer): simply call it first, before writing the
  65          * lines.
  66          */
  67         public void writeLine(Object[] tokens) {
  68                 try {
  69                         for (int i = 0; i < tokens.length; i++) {
  70                                 if (tokens[i] == null) {
  71                                         // TODO configure how to deal with null
  72                                         writeToken("");
  73                                 } else {
  74                                         writeToken(tokens[i].toString());
  75                                 }
  76                                 if (i != (tokens.length - 1))
  77                                         out.write(separator);
  78                         }
  79                         out.write('\n');
  80                         out.flush();
  81                 } catch (IOException e) {
  82                         throw new UtilsException("Could not write " + tokens, e);
  83                 }
  84         }
  85
  86         protected void writeToken(String token) throws IOException {
  87                 // +2 for possible quotes, another +2 assuming there would be an already
  88                 // quoted string where quotes needs to be duplicated
  89                 // another +2 for safety
  90                 // we don't want to increase buffer size while writing
  91                 StringBuffer buf = new StringBuffer(token.length() + 6);
  92                 char[] arr = token.toCharArray();
  93                 boolean shouldQuote = false;
  94                 for (char c : arr) {
  95                         if (!shouldQuote) {
  96                                 if (c == separator)
  97                                         shouldQuote = true;
  98                                 if (c == '\n')
  99                                         shouldQuote = true;
 100                         }
 101
 102                         if (c == quote) {
 103                                 shouldQuote = true;
 104                                 // duplicate quote
 105                                 buf.append(quote);
 106                         }
 107
 108                         // generic case
 109                         buf.append(c);
 110                 }
 111
 112                 if (shouldQuote == true)
 113                         out.write(quote);
 114                 out.write(buf.toString());
 115                 if (shouldQuote == true)
 116                         out.write(quote);
 117         }
 118
 119         public void setSeparator(char separator) {
 120                 this.separator = separator;
 121         }
 122
 123         public void setQuote(char quote) {
 124                 this.quote = quote;
 125         }
 126
 127 }