com.ghgande.j2mod.modbus.io.NonWordDataHandler Maven / Gradle / Ivy
/*
* Copyright 2002-2016 jamod & j2mod development teams
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.ghgande.j2mod.modbus.io;
import java.io.DataInput;
import java.io.EOFException;
import java.io.IOException;
/**
* Interface implementing a non word data handler for the read/write multiple
* register commands.
*
* This interface can be used by any class which works with multiple words of
* data for a non-standard data item. For example, message may involve data
* items which are floating point values or string.
*
* @author Dieter Wimberger
* @author Steve O'Hara (4energy)
* @version 2.0 (March 2016)
*/
public interface NonWordDataHandler {
/**
* Returns the intermediate raw non-word data.
*
*
* An implementation would need to provide a means of converting between the
* raw byte data and the registers that are present in actual messages.
*
* @return the raw data as byte[].
*/
byte[] getData();
/**
* Reads the non-word raw data based on an arbitrary implemented structure.
*
* @param in the DataInput to read from.
* @param reference to specify the offset as int.
* @param count to specify the amount of bytes as int.
*
* @throws IOException if I/O fails.
* @throws EOFException if the stream ends before all data is read.
*/
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.
*/
int getWordCount();
/**
* Commits the data if it has been read into an intermediate repository.
*
*
* This method is called for a message (for example, a
* WriteMultipleRegistersRequest 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.
*/
int commitUpdate();
/**
* Prepares the raw data, putting it together from a backing data store.
*
*
* This method is called for a message (for example, * ReadMultipleRegistersRequest) when finished with reading, for
* creating a response.
*
* @param reference to specify the offset as int.
* @param count to specify the number of bytes as int.
*/
void prepareData(int reference, int count);
}