basic/runtime/org.argeo.basic.nodeps/src/main/java/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 import org.argeo.ArgeoException;
  12
  13 /** Write in CSV format. */
  14 public class CsvWriter {
  15         private final Writer out;
  16
  17         private char separator = ',';
  18         private char quote = '\"';
  19
  20         /**
  21          * Creates a CSV writer.
  22          *
  23          * @param out
  24          *            the stream to write to. Caller is responsible for closing it.
  25          */
  26         public CsvWriter(OutputStream out) {
  27                 this.out = new OutputStreamWriter(out);
  28         }
  29
  30         /**
  31          * Creates a CSV writer.
  32          *
  33          * @param out
  34          *            the stream to write to. Caller is responsible for closing it.
  35          */
  36         public CsvWriter(OutputStream out, String encoding) {
  37                 try {
  38                         this.out = new OutputStreamWriter(out, encoding);
  39                 } catch (UnsupportedEncodingException e) {
  40                         throw new ArgeoException("Cannot initialize CSV writer", e);
  41                 }
  42         }
  43
  44         /**
  45          * Write a CSV line. Also used to write a header if needed (this is
  46          * transparent for the CSV writer): simply call it first, before writing the
  47          * lines.
  48          */
  49         public void writeLine(List<?> tokens) {
  50                 try {
  51                         Iterator<?> it = tokens.iterator();
  52                         while (it.hasNext()) {
  53                                 writeToken(it.next().toString());
  54                                 if (it.hasNext())
  55                                         out.write(separator);
  56                         }
  57                         out.write('\n');
  58                         out.flush();
  59                 } catch (IOException e) {
  60                         throw new ArgeoException("Could not write " + tokens, e);
  61                 }
  62         }
  63
  64         /**
  65          * Write a CSV line. Also used to write a header if needed (this is
  66          * transparent for the CSV writer): simply call it first, before writing the
  67          * lines.
  68          */
  69         public void writeLine(Object[] tokens) {
  70                 try {
  71                         for (int i = 0; i < tokens.length; i++) {
  72                                 if (tokens[i] == null) {
  73                                         // TODO configure how to deal with null
  74                                         writeToken("");
  75                                 } else {
  76                                         writeToken(tokens[i].toString());
  77                                 }
  78                                 if (i != (tokens.length - 1))
  79                                         out.write(separator);
  80                         }
  81                         out.write('\n');
  82                         out.flush();
  83                 } catch (IOException e) {
  84                         throw new ArgeoException("Could not write " + tokens, e);
  85                 }
  86         }
  87
  88         protected void writeToken(String token) throws IOException {
  89                 // +2 for possible quotes, another +2 assuming there would be an already
  90                 // quoted string where quotes needs to be duplicated
  91                 // another +2 for safety
  92                 // we don't want to increase buffer size while writing
  93                 StringBuffer buf = new StringBuffer(token.length() + 6);
  94                 char[] arr = token.toCharArray();
  95                 boolean shouldQuote = false;
  96                 for (char c : arr) {
  97                         if (!shouldQuote) {
  98                                 if (c == separator)
  99                                         shouldQuote = true;
 100                                 if (c == '\n')
 101                                         shouldQuote = true;
 102                         }
 103
 104                         if (c == quote) {
 105                                 shouldQuote = true;
 106                                 // duplicate quote
 107                                 buf.append(quote);
 108                         }
 109
 110                         // generic case
 111                         buf.append(c);
 112                 }
 113
 114                 if (shouldQuote == true)
 115                         out.write(quote);
 116                 out.write(buf.toString());
 117                 if (shouldQuote == true)
 118                         out.write(quote);
 119         }
 120
 121         public void setSeparator(char separator) {
 122                 this.separator = separator;
 123         }
 124
 125         public void setQuote(char quote) {
 126                 this.quote = quote;
 127         }
 128
 129 }