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bFile and getBinaryStream()

Posted on 2004-10-18
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Last Modified: 2012-06-27
     
      
hi!

can anybody explain why getBinaryStream()  is used and the purpose of variable 'offset' in the following function?
++++++++++++++++++++++
      public AssessTestType select(String typeId) {
            log.debug("start");
            String sql =
                  "SELECT test_type_title, test_template_xml, test_template_xsl"
                        + " FROM Assess_Test_Types WHERE assess_test_type_id="
                        + typeId;

            AssessTestType testType = null;
            Statement stmt = null;
            ResultSet rs = null;

            try {
                  stmt = db.createStatement();
                  rs = stmt.executeQuery(sql);

                  if (rs.next()) {
                        testType = new AssessTestType();
                        testType.setTestTypeId(typeId);
                        testType.setTypeTitle(rs.getString("test_type_title"));

                        String[] bfileNames =
                              { "test_template_xml", "test_template_xsl" };
                        String[] xmlXslOut = new String[2];

                        try {
                              for (int i = 0; i < 2; i++) {
                                    StringBuffer tmpBuffer = new StringBuffer();
                                    // Note : Using Oracle Extension oracle.sql.BFILE to get BFILE Locator
                                    oracle.sql.BFILE bfile = null;
                                    bfile = ((OracleResultSet) rs).getBFILE(bfileNames[i]);
                                    
                                    if (bfile == null) {
                                          if ("test_template_xsl".equals(bfileNames[i])) {
                                                xmlXslOut[i] = getGenericXSL();
                                          }
                                    } else { // bfile is not null

                                          // Get the BFILE Locator
                                          // Open the file with openFile Method of oracle.sql.BFILE class
                                          bfile.openFile();

                                          InputStream is = bfile.getBinaryStream();
                                          int offset = 1024;
                                          int len = 0;
                                          byte[] buffer = new byte[offset];

                                          while ((len = is.read(buffer)) > 0) {
                                                tmpBuffer.append(new String(buffer, 0, len));
                                          }
                                          xmlXslOut[i] = tmpBuffer.toString();
                                          log.debug(
                                                "String Size: "
                                                      + xmlXslOut[i].getBytes().length);
                                          log.debug("Returned XML: \n" + xmlXslOut[i]);

                                          is.close();
                                          bfile.closeFile();

                                          is = null;
                                    }
                              }
                        } catch (SQLException e) {
                              log.error(e);
                        } catch (IOException e) {
                              log.error(e);
                        }

                        testType.setXmlTemplate(xmlXslOut[0]);
                        testType.setHtmlXSLFile(xmlXslOut[1]);

                  }
            } catch (SQLException e) {
                  log.error(e);
            } finally {
                  try {
                        if (rs != null)
                              rs.close();
                        if (stmt != null)
                              stmt.close();
                  } catch (SQLException e1) {
                        log.error(e1);
                  }
            }

            return testType;
      }
++++++++++++
thanks,
0
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Question by:dkim18
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5 Comments
 
LVL 86

Accepted Solution

by:
CEHJ earned 125 total points
ID: 12342372
These are binary fields to hold files that are being retrieved, hence the use of streams to get the files. Personally i think CLOB should be used or Unicode can't really be supported without doing one's own decoding
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 12342393
'offset' is a misleading name. All it does in the above is to specify the buffer size for the file read
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Expert Comment

by:objects
ID: 12342833
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