DelimitedTextTableReader


1   package prefuse.data.io;
2   
3   import java.io.BufferedReader  ;
4   import java.io.IOException  ;
5   import java.io.InputStream  ;
6   import java.io.InputStreamReader  ;
7   
8   import prefuse.data.parser.DataParseException;
9   import prefuse.data.parser.ParserFactory;
10  
11  /**
12   * TableReader for delimited text files, such as tab-delimited or
13   * pipe-delimited text files. Such files typically list one row of table
14   * data per line of the file, using a designated character such as a tab
15   * (\t) or pipe (|) to demarcate different data columns. This class
16   * allows you to select any regular expression as the column
17   * delimiter.
18   * 
19   * @author <a HREF="http://jheer.org">jeffrey heer</a>
20   */
21  public class DelimitedTextTableReader extends AbstractTextTableReader {
22  
23      private String   m_delim;
24     
25      /**
26       * Create a new DelimitedTextTableReader for reading tab-delimited files
27       * using a default parser factory.
28       */
29      public DelimitedTextTableReader() {
30          this("\t");
31      }
32      
33      /**
34       * Create a new DelimitedTextTableReader for reading tab-delimited files.
35       * @param parserFactory the ParserFactory to use for parsing text strings
36       * into table values.
37       */
38      public DelimitedTextTableReader(ParserFactory parserFactory) {
39          this("\t", parserFactory);
40      }
41      
42      /**
43       * Create a new DelimitedTextTableReader using a default parser factory.
44       * @param delimiterRegex a regular expression string indicating the
45       * delimiter to use to separate column values
46       */
47      public DelimitedTextTableReader(String   delimiterRegex) {
48          m_delim = delimiterRegex;
49      }
50      
51      /**
52       * Create a new DelimitedTextTableReader.
53       * @param delimiterRegex a regular expression string indicating the
54       * delimiter to use to separate column values
55       * @param pf the ParserFactory to use for parsing text strings
56       * into table values.
57       */
58      public DelimitedTextTableReader(String   delimiterRegex, ParserFactory pf) {
59          super(pf);
60          m_delim = delimiterRegex;
61      }
62      
63      // ------------------------------------------------------------------------
64      
65      /**
66       * @see prefuse.data.io.AbstractTextTableReader#read(java.io.InputStream, prefuse.data.io.TableReadListener)
67       */
68      protected void read(InputStream   is, TableReadListener trl)
69              throws IOException  , DataParseException
70      {
71          String   line;
72          int lineno   = 0;
73          
74          BufferedReader   br = new BufferedReader  (new InputStreamReader  (is));
75          while ( (line=br.readLine()) != null ) {
76              // increment the line number
77              ++lineno;
78              
79              // split on tab character
80              String  [] cols = line.split(m_delim);
81              for ( int i=0; i<cols.length; ++i ) {
82                  trl.readValue(lineno, i+1, cols[i]);
83              }
84          }
85      }
86  
87  } // end of class DelimitedTextTableReader
88
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