| /* ObjectInput.java -- Read object data from a stream |
| Copyright (C) 1998 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| As a special exception, if you link this library with other files to |
| produce an executable, this library does not by itself cause the |
| resulting executable to be covered by the GNU General Public License. |
| This exception does not however invalidate any other reasons why the |
| executable file might be covered by the GNU General Public License. */ |
| |
| |
| package java.io; |
| |
| /** |
| * This interface extends the <code>DataInput</code> interface to provide a |
| * facility to read objects as well as primitive types from a stream. It |
| * also has methods that allow input to be done in a manner similar to |
| * <code>InputStream</code> |
| * |
| * @version 0.0 |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| */ |
| public abstract interface ObjectInput extends DataInput |
| { |
| |
| /** |
| * This method returns the number of bytes that can be read without |
| * blocking. |
| * |
| * @return The number of bytes available before blocking |
| * |
| * @exception IOException If an error occurs |
| */ |
| public abstract int |
| available() throws IOException; |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method reading a byte of data from a stream. It returns that byte |
| * as an int. This method blocks if no data is available to be read. |
| * |
| * @return The byte of data read |
| * |
| * @exception IOException If an error occurs |
| */ |
| public abstract int |
| read() throws IOException; |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method reads raw bytes and stores them them a byte array buffer. |
| * Note that this method will block if no data is available. However, |
| * it will not necessarily block until it fills the entire buffer. That is, |
| * a "short count" is possible. |
| * |
| * @param buf The byte array to receive the data read |
| * |
| * @return The actual number fo bytes read or -1 if end of stream |
| * |
| * @exception IOException If an error occurs |
| */ |
| public abstract int |
| read(byte[] buf) throws IOException; |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method reads raw bytes and stores them in a byte array buffer |
| * <code>buf</code> starting at position <code>offset</code> into the buffer. A |
| * maximum of <code>len</code> bytes will be read. Note that this method |
| * blocks if no data is available, but will not necessarily block until |
| * it can read <code>len</code> bytes of data. That is, a "short count" is |
| * possible. |
| * |
| * @param buf The byte array to receive the data read |
| * @param offset The offset into @code{buf} to start storing data |
| * @param len The maximum number of bytes to read |
| * |
| * @return The actual number fo bytes read or -1 if end of stream |
| * |
| * @exception IOException If an error occurs |
| */ |
| public abstract int |
| read(byte[] buf, int offset, int len) throws IOException; |
| |
| /*************************************************************************/ |
| |
| /** |
| * Reads an object instance and returns it. If the class for the object |
| * being read cannot be found, then a ClassNotFoundException will |
| * be thrown. |
| * |
| * @return The object instance that was read |
| * |
| * @exception ClassNotFoundException If a class for the object cannot be found |
| * @exception IOException If an error occurs |
| */ |
| public abstract Object |
| readObject() throws ClassNotFoundException, IOException; |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method causes the specified number of bytes to be read and |
| * discarded. It is possible that fewer than the requested number of bytes |
| * will actually be skipped. |
| * |
| * @param num_bytes The number of bytes to skip |
| * |
| * @return The actual number of bytes skipped |
| * |
| * @exception IOException If an error occurs |
| */ |
| public abstract long |
| skip(long num_bytes) throws IOException; |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method closes the input source |
| * |
| * @exception IOException If an error occurs |
| */ |
| public abstract void |
| close() throws IOException; |
| |
| } // interface ObjectInput |
| |