objectinputstream.java

gcc的组建

	      /* We do not want to modify transient fields. They should
	       * be left to 0.
	       */
	      try
		{
		  Field f = clazz.forClass().getDeclaredField(name);
		  if (Modifier.isTransient(f.getModifiers()))
		    throw new IllegalArgumentException
		      ("no such field (non transient) " + name);
		  if (field == null && f.getType() != type)
		    throw new IllegalArgumentException
		      ("Invalid requested type for field " + name);
		}
	      catch (NoSuchFieldException e)
		{
		  if (field == null)
		    throw new IllegalArgumentException(e.getMessage());
		}
	       
	    }
	}
      };

    fieldsAlreadyRead = true;
    return prereadFields;
  }

  /**
   * Protected constructor that allows subclasses to override
   * deserialization.  This constructor should be called by subclasses
   * that wish to override <code>readObject (Object)</code>.  This
   * method does a security check <i>NOTE: currently not
   * implemented</i>, then sets a flag that informs
   * <code>readObject (Object)</code> to call the subclasses
   * <code>readObjectOverride (Object)</code> method.
   *
   * @see #readObjectOverride()
   */
  protected ObjectInputStream()
    throws IOException, SecurityException
  {
    SecurityManager sec_man = System.getSecurityManager();
    if (sec_man != null)
      sec_man.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
    this.useSubclassMethod = true;
  }

  /**
   * This method allows subclasses to override the default
   * de serialization mechanism provided by
   * <code>ObjectInputStream</code>.  To make this method be used for
   * writing objects, subclasses must invoke the 0-argument
   * constructor on this class from their constructor.
   *
   * @see #ObjectInputStream()
   */
  protected Object readObjectOverride()
    throws ClassNotFoundException, IOException, OptionalDataException
  {
    throw new IOException("Subclass of ObjectInputStream must implement readObjectOverride");
  }

  /**
   * Assigns the next available handle to <code>obj</code>.
   *
   * @param obj The object for which we want a new handle.
   * @return A valid handle for the specified object.
   */
  private int assignNewHandle(Object obj)
  {
    this.objectLookupTable.put(new Integer(this.nextOID),
			       new ObjectIdentityWrapper(obj));
    return this.nextOID++;
  }

  private Object processResolution(ObjectStreamClass osc, Object obj, int handle)
    throws IOException
  {
    if (osc != null && obj instanceof Serializable)
      {
	try
	  {
	    Method m = osc.readResolveMethod; 
	    if(m != null)
	    {
		obj = m.invoke(obj, new Object[] {});
	    }
	  }
	catch (IllegalAccessException ignore)
	  {
	  }
	catch (InvocationTargetException exception)
	  {
	    Throwable cause = exception.getCause();
	    if (cause instanceof ObjectStreamException)
	      throw (ObjectStreamException) cause;
	    else if (cause instanceof RuntimeException)
	      throw (RuntimeException) cause;
	    else if (cause instanceof Error)
	      throw (Error) cause;
	  }
      }

    if (this.resolveEnabled)
      obj = resolveObject(obj);

    this.objectLookupTable.put(new Integer(handle),
			       new ObjectIdentityWrapper(obj));

    return obj;
  }

  private void clearHandles()
  {
    this.objectLookupTable.clear();
    this.nextOID = baseWireHandle;
  }

  private void readNextBlock() throws IOException
  {
    readNextBlock(this.realInputStream.readByte());
  }

  private void readNextBlock(byte marker) throws IOException
  {
    if (marker == TC_BLOCKDATA)
      {
	if(dump) dumpElement("BLOCK DATA SIZE=");
	this.blockDataBytes = this.realInputStream.readUnsignedByte();
	if(dump) dumpElementln (Integer.toString(this.blockDataBytes));
      }
    else if (marker == TC_BLOCKDATALONG)
      {
	if(dump) dumpElement("BLOCK DATA LONG SIZE=");
	this.blockDataBytes = this.realInputStream.readInt();
	if(dump) dumpElementln (Integer.toString(this.blockDataBytes));
      }
    else
      {
	throw new EOFException("Attempt to read primitive data, but no data block is active.");
      }

    if (this.blockData.length < this.blockDataBytes)
      this.blockData = new byte[this.blockDataBytes];

    this.realInputStream.readFully (this.blockData, 0, this.blockDataBytes);
    this.blockDataPosition = 0;
  }

  private void readArrayElements (Object array, Class clazz)
    throws ClassNotFoundException, IOException
  {
    if (clazz.isPrimitive())
      {
	if (clazz == Boolean.TYPE)
	  {
	    boolean[] cast_array = (boolean[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readBoolean();
	    return;
	  }
	if (clazz == Byte.TYPE)
	  {
	    byte[] cast_array = (byte[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readByte();
	    return;
	  }
	if (clazz == Character.TYPE)
	  {
	    char[] cast_array = (char[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readChar();
	    return;
	  }
	if (clazz == Double.TYPE)
	  {
	    double[] cast_array = (double[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readDouble();
	    return;
	  }
	if (clazz == Float.TYPE)
	  {
	    float[] cast_array = (float[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readFloat();
	    return;
	  }
	if (clazz == Integer.TYPE)
	  {
	    int[] cast_array = (int[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readInt();
	    return;
	  }
	if (clazz == Long.TYPE)
	  {
	    long[] cast_array = (long[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readLong();
	    return;
	  }
	if (clazz == Short.TYPE)
	  {
	    short[] cast_array = (short[])array;
	    for (int i=0; i < cast_array.length; i++)
	      cast_array[i] = this.realInputStream.readShort();
	    return;
	  }
      }
    else
      {
	Object[] cast_array = (Object[])array;
	for (int i=0; i < cast_array.length; i++)
 	  cast_array[i] = readObject();
      }
  }

  private void readFields (Object obj, ObjectStreamClass stream_osc)
    throws ClassNotFoundException, IOException
  {
    ObjectStreamField[] fields = stream_osc.fieldMapping;

    for (int i = 0; i < fields.length; i += 2)
      {
	ObjectStreamField stream_field = fields[i];
	ObjectStreamField real_field = fields[i + 1];
	boolean read_value = (stream_field != null && stream_field.getOffset() >= 0 && stream_field.isToSet());
	boolean set_value = (real_field != null && real_field.isToSet());
	String field_name;
	char type;

	if (stream_field != null)
	  {
	    field_name = stream_field.getName();
	    type = stream_field.getTypeCode();
	  }
	else
	  {
	    field_name = real_field.getName();
	    type = real_field.getTypeCode();
	  }
	
	switch(type)
	  {
	  case 'Z':
	    {
	      boolean value =
		read_value ? this.realInputStream.readBoolean() : false;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setBooleanField(obj, value);
	      break;
	    }
	  case 'B':
	    {
	      byte value =
		read_value ? this.realInputStream.readByte() : 0;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setByteField(obj, value);
	      break;
	    }
	  case 'C':
	    {
	      char value =
		read_value ? this.realInputStream.readChar(): 0;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setCharField(obj, value);
	      break;
	    }
	  case 'D':
	    {
	      double value =
		read_value ? this.realInputStream.readDouble() : 0;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setDoubleField(obj, value);
	      break;
	    }
	  case 'F':
	    {
	      float value =
		read_value ? this.realInputStream.readFloat() : 0;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setFloatField(obj, value);
	      break;
	    }
	  case 'I':
	    {
	      int value =
		read_value ? this.realInputStream.readInt() : 0;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setIntField(obj, value);
	      break;
	    }
	  case 'J':
	    {
	      long value =
		read_value ? this.realInputStream.readLong() : 0;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setLongField(obj, value);
	      break;
	    }
	  case 'S':
	    {
	      short value =
		read_value ? this.realInputStream.readShort() : 0;
	      if (dump && read_value && set_value)
		dumpElementln("  " + field_name + ": " + value);
	      if (set_value)
		real_field.setShortField(obj, value);
	      break;
	    }
	  case 'L':
	  case '[':
	    {
	      Object value =
		read_value ? readObject() : null;
	      if (set_value)
		real_field.setObjectField(obj, value);
	      break;
	    }
	  default:
	    throw new InternalError("Invalid type code: " + type);
	  }
      }
  }
  
  // Toggles writing primitive data to block-data buffer.
  private boolean setBlockDataMode (boolean on)
  {
    boolean oldmode = this.readDataFromBlock;
    this.readDataFromBlock = on;

    if (on)
      this.dataInputStream = this.blockDataInput;
    else
      this.dataInputStream = this.realInputStream;
    return oldmode;
  }

  // returns a new instance of REAL_CLASS that has been constructed
  // only to the level of CONSTRUCTOR_CLASS (a super class of REAL_CLASS)
  private Object newObject (Class real_class, Constructor constructor)
    throws ClassNotFoundException, IOException
  {
    if (constructor == null)
        throw new InvalidClassException("Missing accessible no-arg base class constructor for " + real_class.getName()); 
    try
      {
	return allocateObject(real_class, constructor.getDeclaringClass(), constructor);
      }
    catch (InstantiationException e)
      {
        throw new ClassNotFoundException
		("Instance of " + real_class + " could not be created");
      }
  }

  // runs all registered ObjectInputValidations in prioritized order
  // on OBJ
  private void invokeValidators() throws InvalidObjectException
  {
    Object[] validators = new Object[this.validators.size()];
    this.validators.copyInto (validators);
    Arrays.sort (validators);

    try
      {
	for (int i=0; i < validators.length; i++)
	  ((ObjectInputValidation)validators[i]).validateObject();
      }
    finally
      {
	this.validators.removeAllElements();
      }
  }

  private void callReadMethod (Method readObject, Class klass, Object obj)
    throws ClassNotFoundException, IOException
  {
    try
      {
	readObject.invoke(obj, new Object[] { this });
      }
    catch (InvocationTargetException x)
      {
        /* Rethrow if possible. */
	Throwable exception = x.getTargetException();
	if (exception instanceof RuntimeException)
	  throw (RuntimeException) exception;
	if (exception instanceof IOException)
	  throw (IOException) exception;
        if (exception instanceof ClassNotFoundException)
          throw (ClassNotFoundException) exception;

	throw new IOException("Exception thrown from readObject() on " +
			       klass + ": " + exception.getClass().getName());
      }
    catch (Exception x)
      {
	throw new IOException("Failure invoking readObject() on " +
			       klass + ": " + x.getClass().getName());
      }

    // Invalidate fields which has been read through readFields.
    prereadFields = null;
  }
    
  private native Object allocateObject(Class clazz, Class constr_clazz, Constructor constructor)
    throws InstantiationException;

  private static final int BUFFER_SIZE = 1024;

  private DataInputStream realInputStream;
  private DataInputStream dataInputStream;
  private DataInputStream blockDataInput;
  private int blockDataPosition;
  private int blockDataBytes;
  private byte[] blockData;
  private boolean useSubclassMethod;
  private int nextOID;
  private boolean resolveEnabled;
  private Hashtable objectLookupTable;
  private Object currentObject;
  private ObjectStreamClass currentObjectStreamClass;
  private boolean readDataFromBlock;
  private boolean isDeserializing;
  private boolean fieldsAlreadyRead;
  private Vector validators;
  private Hashtable classLookupTable;
  private GetField prereadFields;

  private ClassLoader callersClassLoader;
  private static boolean dump;

  // The nesting depth for debugging output
  private int depth = 0;

  private void dumpElement (String msg)
  {
    System.out.print(msg);
  }
  
  private void dumpElementln (String msg)
  {
    System.out.println(msg);
    for (int i = 0; i < depth; i++)
      System.out.print (" ");
    System.out.print (Thread.currentThread() + ": ");
  }

  static
  {
    if (Configuration.INIT_LOAD_LIBRARY)
      {
	System.loadLibrary ("javaio");
      }
  }

  // used to keep a prioritized list of object validators
  private static final class ValidatorAndPriority implements Comparable
  {
    int priority;
    ObjectInputValidation validator;

    ValidatorAndPriority (ObjectInputValidation validator, int priority)
    {
      this.priority = priority;
      this.validator = validator;
    }

    public int compareTo (Object o)
    {
      ValidatorAndPriority vap = (ValidatorAndPriority)o;
      return this.priority - vap.priority;
    }
  }
}