objectcreator.java

linux下建立JAVA虚拟机的源码KAFFE

  /**
   * Converts the given IDL name to class name.
   * 
   * @param IDL the idl name.
   * 
   */
  protected static String toClassName(String prefix, String IDL)
  {
    String s = IDL;
    int a = s.indexOf(':') + 1;
    int b = s.lastIndexOf(':');

    s = IDL.substring(a, b);

    if (s.startsWith(OMG_PREFIX))
      s = prefix + s.substring(OMG_PREFIX.length());

    return s.replace('/', '.');
  }

  /**
   * Converts the given IDL name to class name and tries to load the matching
   * class. The OMG prefix (omg.org) is replaced by the java prefix org.omg. No
   * other prefixes are added.
   * 
   * @param IDL the idl name.
   * 
   * @return the matching class or null if no such is available.
   */
  public static Class Idl2class(String IDL)
  {
    synchronized (m_classes)
      {
        Class c = (Class) m_classes.get(IDL);

        if (c != null)
          return c;
        else
          {
            String s = IDL;
            int a = s.indexOf(':') + 1;
            int b = s.lastIndexOf(':');

            s = IDL.substring(a, b);

            if (s.startsWith(OMG_PREFIX))
              s = JAVA_PREFIX + s.substring(OMG_PREFIX.length());

            String cn = s.replace('/', '.');

            try
              {
                c = forName(cn);
                m_classes.put(IDL, c);
                return c;
              }
            catch (ClassNotFoundException ex)
              {
                return null;
              }
          }
      }
  }

  /**
   * Converts the given IDL name to class name, tries to load the matching class
   * and create an object instance with parameterless constructor. The OMG
   * prefix (omg.org) is replaced by the java prefix org.omg. No other prefixes
   * are added.
   * 
   * @param IDL the idl name.
   * 
   * @return instantiated object instance or null if such attempt was not
   * successful.
   */
  public static java.lang.Object Idl2Object(String IDL)
  {
    Class cx = Idl2class(IDL);

    try
      {
        if (cx != null)
          return cx.newInstance();
        else
          return null;
      }
    catch (Exception ex)
      {
        return null;
      }
  }

  /**
   * Convert the class name to IDL or RMI name (repository id). If the class
   * inherits from IDLEntity, ValueBase or SystemException, returns repository
   * Id in the IDL:(..) form. If it does not, returns repository Id in the
   * RMI:(..) form.
   * 
   * @param cx the class for that the name must be computed.
   * 
   * @return the idl or rmi name.
   */
  public static synchronized String getRepositoryId(Class cx)
  {
    String name = (String) m_names.get(cx);
    if (name != null)
      return name;

    String cn = cx.getName();
    if (!(IDLEntity.class.isAssignableFrom(cx)
      || ValueBase.class.isAssignableFrom(cx) || SystemException.class.isAssignableFrom(cx)))
      {
        // Not an IDL entity.
        name = Util.createValueHandler().getRMIRepositoryID(cx);
      }
    else
      {
        if (cn.startsWith(JAVA_PREFIX))
          cn = OMG_PREFIX
            + cn.substring(JAVA_PREFIX.length()).replace('.', '/');
        else if (cn.startsWith(CLASSPATH_PREFIX))
          cn = OMG_PREFIX
            + cn.substring(CLASSPATH_PREFIX.length()).replace('.', '/');

        name = "IDL:" + cn + ":1.0";
      }
    m_names.put(cx, name);
    return name;
  }

  /**
   * Insert the passed parameter into the given Any, assuming that the helper
   * class is available. The helper class must have the "Helper" suffix and be
   * in the same package as the class of the object being inserted.
   * 
   * @param into the target to insert.
   * 
   * @param object the object to insert. It can be any object as far as the
   * corresponding helper is provided.
   * 
   * @return true on success, false otherwise.
   */
  public static boolean insertWithHelper(Any into, Object object)
  {
    try
      {
        String helperClassName = object.getClass().getName() + "Helper";
        Class helperClass = forName(helperClassName);

        Method insert = helperClass.getMethod("insert", new Class[] {
          Any.class, object.getClass() });

        insert.invoke(null, new Object[] { into, object });

        return true;
      }
    catch (Exception exc)
      {
        // Failed due some reason.
        return false;
      }
  }

  /**
   * Insert the system exception into the given Any.
   */
  public static boolean insertSysException(Any into, SystemException exception)
  {
    try
      {
        BufferedCdrOutput output = new BufferedCdrOutput();

        String m_exception_id = getRepositoryId(exception.getClass());
        output.write_string(m_exception_id);
        output.write_ulong(exception.minor);
        CompletionStatusHelper.write(output, exception.completed);

        String name = getDefaultName(m_exception_id);

        GeneralHolder h = new GeneralHolder(output);

        into.insert_Streamable(h);

        RecordTypeCode r = new RecordTypeCode(TCKind.tk_except);
        r.setId(m_exception_id);
        r.setName(name);
        into.type(r);

        return true;
      }
    catch (Exception ex)
      {
        ex.printStackTrace();
        return false;
      }
  }

  /**
   * Get the type name from the IDL string.
   */
  public static String getDefaultName(String idl)
  {
    int f1 = idl.lastIndexOf("/");
    int p1 = (f1 < 0) ? 0 : f1;
    int p2 = idl.indexOf(":", p1);
    if (p2 < 0)
      p2 = idl.length();

    String name = idl.substring(f1 + 1, p2);
    return name;
  }

  /**
   * Insert this exception into the given Any. On failure, insert the UNKNOWN
   * exception.
   */
  public static void insertException(Any into, Throwable exception)
  {
    boolean ok = false;
    if (exception instanceof SystemException)
      ok = insertSysException(into, (SystemException) exception);
    else if (exception instanceof UserException)
      ok = insertWithHelper(into, exception);

    if (!ok)
      ok = insertSysException(into, new UNKNOWN());
    if (!ok)
      throw new InternalError("Exception wrapping broken");
  }

  /**
   * Find helper for the class with the given name.
   */
  public static Class findHelper(String idl)
  {
    synchronized (m_helpers)
      {
        Class c = (Class) m_helpers.get(idl);
        if (c != null)
          return c;
        try
          {
            String helper = toHelperName(idl);
            c = forName(helper);

            m_helpers.put(idl, c);
            return c;
          }
        catch (Exception ex)
          {
            return null;
          }
      }
  }
  
  /**
   * Load the class with the given name. This method tries to use the context
   * class loader first. If this fails, it searches for the suitable class
   * loader in the caller stack trace. This method is a central point where all
   * requests to find a class by name are delegated.
   */
  public static Class forName(String className) throws ClassNotFoundException
  {
    try
      {
        return Class.forName(className, true,
                             Thread.currentThread().getContextClassLoader());
      }
    catch (ClassNotFoundException nex)
      {
        /**
         * Returns the first user defined class loader on the call stack, or
         * null when no non-null class loader was found.
         */
        Class[] ctx = VMStackWalker.getClassContext();
        for (int i = 0; i < ctx.length; i++)
          {
            // Since we live in a class loaded by the bootstrap
            // class loader, getClassLoader is safe to call without
            // needing to be wrapped in a privileged action.
            ClassLoader cl = ctx[i].getClassLoader();
            try
              {
                if (cl != null)
                  return Class.forName(className, true, cl);
              }
            catch (ClassNotFoundException nex2)
              {
                // Try next.
              }
          }
      }
    throw new ClassNotFoundException(className);
  }
}