Beispiel #1
0
 /**
  * Decodes a String from the database representing a clob object. See getDbDescription().
  *
  * @param os an ObjectStore that the clob is stored in
  * @param description the description from the database
  * @return a ClobAccess object, or a subclass
  */
 public static ClobAccess decodeDbDescription(ObjectStore os, String description) {
   String[] parts = description.split(",");
   ClobAccess clob = new ClobAccess(os, new Clob(Integer.parseInt(parts[0])));
   if (parts.length >= 3) {
     int offset = Integer.parseInt(parts[1]);
     int length = Integer.parseInt(parts[2]);
     clob = clob.subSequence(offset, offset + length);
   }
   String className = null;
   if (parts.length == 2) {
     className = parts[1];
   } else if (parts.length == 4) {
     className = parts[3];
   }
   if (className != null) {
     // So, className is a class that extends ClobAccess. We expect there to be a static
     // method called getFactory() that returns a ClobAccessSubclassFactory object that we
     // can store in a cache, which will call the constructor quickly.
     Map<String, ClobAccessSubclassFactory> factoryCache = subclassFactoryCache.get();
     ClobAccessSubclassFactory factory = factoryCache.get(className);
     if (factory == null) {
       try {
         Class<?> subclass = Class.forName(className);
         Method subMethod = subclass.getMethod("getFactory");
         factory = (ClobAccessSubclassFactory) subMethod.invoke(null);
         factoryCache.put(className, factory);
       } catch (ClassNotFoundException e) {
         throw new RuntimeException(
             "Could not read Clob subclass " + className + " from database.", e);
       } catch (NoSuchMethodException e) {
         throw new RuntimeException(
             "Could not read Clob subclass " + className + " from database.", e);
       } catch (InvocationTargetException e) {
         throw new RuntimeException(
             "Could not read Clob subclass " + className + " from database.", e);
       } catch (IllegalAccessException e) {
         throw new RuntimeException(
             "Could not read Clob subclass " + className + " from database.", e);
       }
     }
     clob = factory.invokeConstructor(clob);
   }
   return clob;
 }
 public void testClob() throws Exception {
   Clob clob = writer.createClob();
   writer.replaceClob(clob, "Monkey");
   ClobAccess ca = new ClobAccess(writer, clob);
   assertEquals("Monkey", ca.toString());
   StringBuilder longString = new StringBuilder();
   for (int i = 0; i < 10000; i++) {
     longString.append("Lots of monkeys. ");
   }
   writer.replaceClob(clob, longString.toString());
   assertEquals("Monkey", ca.toString());
   ca = new ClobAccess(writer, clob);
   assertEquals(170000, ca.length());
   assertEquals(longString.toString(), ca.toString());
   assertEquals('L', ca.charAt(1700));
   assertEquals('L', ca.charAt(16983));
   ClobAccess sub = ca.subSequence(85000, 85016);
   assertEquals("Lots of monkeys.", sub.toString());
   assertEquals(16, sub.length());
 }