CSVTableWriter


1   package prefuse.data.io;
2   
3   import java.io.BufferedOutputStream  ;
4   import java.io.OutputStream  ;
5   import java.io.PrintStream  ;
6   
7   import prefuse.data.Table;
8   import prefuse.util.collections.IntIterator;
9   
10  /**
11   * TableWriter that writes out a text table in the comma-separated-values
12   * format. By default, a header row containing the column names is included
13   * in the output.
14   * 
15   * @author <a HREF="http://jheer.org">jeffrey heer</a>
16   */
17  public class CSVTableWriter extends AbstractTableWriter {
18  
19      private boolean m_printHeader;
20      
21      /**
22       * Create a new CSVTableWriter that writes comma separated values files.
23       */
24      public CSVTableWriter() {
25          this(true);
26      }
27      
28      /**
29       * Create a new CSVTableWriter.
30       * @param printHeader indicates if a header row should be printed
31       */
32      public CSVTableWriter(boolean printHeader) {
33          m_printHeader = printHeader;
34      }
35  
36      // ------------------------------------------------------------------------
37  
38      /**
39       * Indicates if this writer will write a header row with the column names.
40       * @return true if a header row will be printed, false otherwise
41       */
42      public boolean isPrintHeader() {
43          return m_printHeader;
44      }
45  
46      /**
47       * Sets if this writer will write a header row with the column names.
48       * @param printHeader true to print a header row, false otherwise
49       */
50      public void setPrintHeader(boolean printHeader) {
51          m_printHeader = printHeader;
52      }    
53      
54      // ------------------------------------------------------------------------
55  
56      /**
57       * @see prefuse.data.io.TableWriter#writeTable(prefuse.data.Table, java.io.OutputStream)
58       */
59      public void writeTable(Table table, OutputStream   os) throws DataIOException {
60          try {            
61              // get print stream
62              PrintStream   out = new PrintStream  (new BufferedOutputStream  (os));
63              
64              // write out header row
65              if ( m_printHeader ) {
66                  for ( int i=0; i<table.getColumnCount(); ++i ) {
67                      if ( i>0 ) out.print(',');
68                      out.print(makeCSVSafe(table.getColumnName(i)));
69                  }
70                  out.println();
71              }
72              
73              // write out data
74              for ( IntIterator rows = table.rows(); rows.hasNext(); ) {
75                  int row = rows.nextInt();
76                  for ( int i=0; i<table.getColumnCount(); ++i ) {
77                      if ( i>0 ) out.print(',');
78                      String   str = table.getString(row, table.getColumnName(i));
79                      out.print(makeCSVSafe(str));
80                  }
81                  out.println();
82              }
83              
84              // finish up
85              out.flush();
86          } catch ( Exception   e ) {
87              throw new DataIOException(e);
88          }
89      }
90      
91      private String   makeCSVSafe(String   s) {
92          int q = -1;
93          if ( (q=s.indexOf('\"')) >= 0 ||
94               s.indexOf(',')  >= 0 || s.indexOf('\n') >= 0 ||
95               Character.isWhitespace(s.charAt(0)) ||
96               Character.isWhitespace(s.charAt(s.length()-1)) )
97          {
98              if ( q >= 0 ) s = s.replaceAll("\"", "\"\"");
99              s = "\""+s+"\"";
100         }
101         return s;
102     }
103 
104 } // end of class CSVTableWriter
105
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