ResultRegistry.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.rfxcom.internal;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Future;

import org.openhab.binding.rfxcom.internal.messages.RFXComTransmitterMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The purpose is to register and provide {@link Future futures} to conveniently receive results.
 *
 * @author Jürgen Richtsfeld
 * @since 1.7
 */
class ResultRegistry {
    private static final Logger logger = LoggerFactory.getLogger(ResultRegistry.class);

    private final Map<Byte, RFXComResponse> results = new HashMap<Byte, RFXComResponse>(40);

    public Future<RFXComTransmitterMessage> registerCommand(final byte seqNumber) {
        synchronized (results) {
            final Future<RFXComTransmitterMessage> old = results.get(seqNumber);
            assert old == null : "found a leftover future";
            if (old != null) {
                logger.warn("cancelling old future of sequence number" + seqNumber);
                old.cancel(true);
            }

            final RFXComResponse result = new RFXComResponse();
            results.put(seqNumber, result);
            return result;
        }
    }

    public void responseReceived(final RFXComTransmitterMessage response) {
        synchronized (results) {
            final RFXComResponse future = results.get(response.seqNbr);
            if (future != null) {
                logger.debug("Transmitter response received:\n{}", response.toString());
                future.set(response);
                results.remove(response.seqNbr);
            } else {
                logger.warn("Transmitter response received for sequence {} but no listener is registered:\n{}",
                        response.seqNbr, response.toString());
            }
        }
    }

}