P1TelegramParserState.java

/**
 * Copyright (c) 2010-2016 by the respective copyright holders.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.openhab.binding.dsmr.internal.p1telegram;

/**
 * P1TelegramParserState stores the state of the P1TelegramParser The state
 * consists of the following attributes:
 * <ul>
 * <li>receivedData (all parsed data of a single P1 telegram)
 * <li>header (the header string of a single P1 telegram)
 * <li>obisId (the last OBIS Identifier seen or parsing)
 * <li>obisValue (the last OBIS value seen or parsing)
 * <li>crcValue (the last crc value seen or parsing)
 * <li>state (state in the P1 telegram)
 * </ul>
 *
 * @author mvolaart
 * @since 1.7.0
 */
class P1TelegramParserState {
    static enum State {
        // Wait for the '/' character
        WAIT_FOR_START,
        // '/' character seen
        STARTED,
        // Parsing data after the '/' character
        HEADER,
        // Waiting for the header to end with a CR & LF
        CRLF,
        // Handling OBIS Identifier
        DATA_OBIS_ID,
        // OBIS value start seen '('
        DATA_OBIS_VALUE_START,
        // Parsing OBIS value
        DATA_OBIS_VALUE,
        // OBIS value end seen ')'
        DATA_OBIS_VALUE_END,
        // Parsing CRC value following '!'
        CRC_VALUE
    };

    /* internal state variables */
    private String receivedData = "";
    private String header = "";
    private String obisId = "";
    private String obisValue = "";
    private String crcValue = "";
    private State state = State.WAIT_FOR_START;

    /**
     * Creates a new P1TelegramParser object
     */
    P1TelegramParserState() {
    }

    /**
     * Stores a single character
     * 
     * @param c
     *            the character to store
     */
    void handleCharacter(char c) {

        switch (state) {
            case WAIT_FOR_START:
                // ignore the data
                break;
            case STARTED:
                header += c;
                receivedData += c;
                break;
            case HEADER:
                header += c;
                receivedData += c;
                break;
            case CRLF:
                receivedData += c;
                break;
            case DATA_OBIS_ID:
                obisId += c;
                receivedData += c;
                break;
            case DATA_OBIS_VALUE_START:
                receivedData += c;
                break;
            case DATA_OBIS_VALUE:
                obisValue += c;
                receivedData += c;
                break;
            case DATA_OBIS_VALUE_END:
                receivedData += c;
                break;
            case CRC_VALUE:
                crcValue += c;
                // CRC data is not part of received data
                break;
            default:
                break;
        }
    }

    /**
     * Clear internal state
     */
    private void clearInternalData() {
        header = "";
        obisId = "";
        obisValue = "";
        receivedData = "";
        crcValue = "";
    }

    /**
     * Clears the received OBIS Identifer
     */
    private void clearObisId() {
        obisId = "";
    }

    /**
     * Clears the current OBIS value
     */
    private void clearObisValue() {
        obisValue = "";
    }

    /**
     * @return the state
     */
    State getState() {
        return state;
    }

    /**
     * @param state
     *            the state to set
     */
    void setState(State newState) {
        switch (newState) {
            case WAIT_FOR_START:
                clearInternalData();
                break;
            case DATA_OBIS_ID:
                clearObisId();
                clearObisValue();
                break;
            case DATA_OBIS_VALUE_START:
                break;
            case DATA_OBIS_VALUE:
                clearObisValue();
                break;
            default:
                break;
        }

        state = newState;
    }

    /**
     * @return the meterId
     */
    String getHeader() {
        return header;
    }

    /**
     * @return the obisId
     */
    String getObisId() {
        return obisId;
    }

    /**
     * @return the obisValue
     */
    String getObisValue() {
        return obisValue;
    }

    /**
     * @return the crcValue
     */
    String getCrcValue() {
        return crcValue;
    }

    /**
     * @return the receivedData
     */
    String getReceivedData() {
        return receivedData;
    }

    @Override
    public String toString() {
        return state + ", header = " + header + ", obisId = " + obisId + ", obisValue = " + obisValue;
    }
}