nonworddatahandler.java

jamod is an object oriented implementation of the Modbus protocol, realized 100 in Java. It allows

//License
/***
 * Java Modbus Library (jamod)
 * Copyright (c) 2002-2004, jamod development team
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
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 *
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the author nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS
 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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package net.wimpi.modbus.io;

import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.DataInput;

/**
 * Interface implementing a non word data handler for the
 * read/write multiple register commands (class 0).
 *
 * @author Dieter Wimberger
 * @version 1.2rc1 (09/11/2004)
 */
public interface NonWordDataHandler {

  /**
   * Returns the intermediate raw non-word data.
   *
   * @return the raw data as <tt>byte[]</tt>.
   */
  public byte[] getData();

  /**
   * Reads the non-word raw data based on an arbitrary
   * implemented structure.
   *
   * @param in the <tt>DataInput</tt> to read from.
   * @param reference to specify the offset as <tt>int</tt>.
   * @param count to sepcify the amount of bytes as <tt>int</tt>.
   *
   * @throws IOException if I/O fails.
   * @throws EOFException if the stream ends before all data is read.
   */
  public void readData(DataInput in, int reference, int count)
      throws IOException, EOFException;

  /**
   * Returns the word count of the data.
   * Note that this should be the length of the byte
   * array divided by two.
   *
   * @return the number of words the data consists of.
   */
  public int getWordCount();

  /**
   * Commits the data if it has been read into an intermediate
   * repository.
   * This method is called by a <tt>WriteMultipleRegistersRequest</tt>
   * instance when finished with reading, for creating a response.
   *
   * @return -1 if the commit was successful, a Modbus exception code
   *         valid for the read/write multiple registers commands
   *         otherwise.
   */
  public int commitUpdate();

  /**
   * Prepares the raw data, putting it together from a
   * backing data store.
   * This method is called by a <tt>ReadMultipleRegistersRequest</tt>
   * instance when finshed with reading, for creating a response.
   *
   * @param reference to specify the offset as <tt>int</tt>.
   * @param count to sepcify the amount of bytes as <tt>int</tt>.
   */
  public void prepareData(int reference, int count);

}//NonWordDataHandler