AsciiStreamConverter


1   
2   /*
3    * Copyright (c) 1998 - 2005 Versant Corporation
4    * All rights reserved. This program and the accompanying materials
5    * are made available under the terms of the Eclipse Public License v1.0
6    * which accompanies this distribution, and is available at
7    * http://www.eclipse.org/legal/epl-v10.html
8    *
9    * Contributors:
10   * Versant Corporation - initial API and implementation
11   */
12  package com.versant.core.jdbc.sql.conv;
13  
14  import com.versant.core.jdbc.JdbcConverter;
15  import com.versant.core.jdbc.JdbcConverterFactory;
16  import com.versant.core.jdbc.JdbcTypeRegistry;
17  import com.versant.core.jdbc.metadata.JdbcColumn;
18  
19  import java.sql.PreparedStatement  ;
20  import java.sql.SQLException  ;
21  import java.sql.ResultSet  ;
22  import java.io.*;
23  
24  import javax.jdo.JDOFatalDataStoreException;    //todo: appears only in throws-clause
25  
26  import com.versant.core.common.BindingSupportImpl;
27  
28  /**
29   * This converter converts Strings stored in TEXT or LONGVARCHAR columns to
30   * and from SQL using rs.getAsciiStream and ps.setAsciiStream.
31   * @keep-all
32   */
33  public class AsciiStreamConverter extends JdbcConverterBase {
34  
35      public static class Factory extends NoArgJdbcConverterFactory {
36  
37          private AsciiStreamConverter converter;
38  
39          /**
40           * Create a converter for col using args as parameters. Return null if
41           * no converter is required.
42           */
43          public JdbcConverter createJdbcConverter(JdbcColumn col, Object   args,
44                  JdbcTypeRegistry jdbcTypeRegistry) {
45              if (converter == null) converter = new AsciiStreamConverter();
46              return converter;
47          }
48  
49      }
50  
51      /**
52       * Get the value of col from rs at position index.
53       * @exception SQLException on SQL errors
54       * @exception JDOFatalDataStoreException if the ResultSet value is invalid
55       */
56      public Object   get(ResultSet   rs, int index, JdbcColumn col)
57              throws SQLException  , JDOFatalDataStoreException {
58          try {
59              InputStream in = rs.getAsciiStream(index);
60              if (in == null) return null;
61              return StreamUtils.readAll(in, "UTF8");
62          } catch (IOException x) {
63              throw BindingSupportImpl.getInstance().fatalDatastore(
64                  "Error reading " + col + ": " +
65                  x.getClass().getName() + ": " + x.getMessage(), x);
66          }
67      }
68  
69      /**
70       * Set parameter index on ps to value (for col).
71       * @exception SQLException on SQL errors
72       * @exception JDOFatalDataStoreException if value is invalid
73       */
74      public void set(PreparedStatement   ps, int index, JdbcColumn col, Object   value)
75              throws SQLException  , JDOFatalDataStoreException {
76          if (value == null) {
77              ps.setNull(index, col.jdbcType);
78              return;
79          }
80          String   s = (String  )value;
81          byte[] b = s.getBytes();
82          ps.setAsciiStream(index, new ByteArrayInputStream(b), b.length);
83      }
84  
85      /**
86       * Get the type of our expected value objects (e.g. java.util.Locale
87       * for a converter for Locale's).
88       */
89      public Class   getValueType() {
90          return String  .class;
91      }
92  }
93  
94
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