org.jmqtt.core.codec.UnsubscribeDecoder.java Source code

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Here is the source code for org.jmqtt.core.codec.UnsubscribeDecoder.java

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/*
 * Copyright (c) 2012-2015 The original author or authors
 * ------------------------------------------------------
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Apache License v2.0 which accompanies this distribution.
 *
 * The Eclipse Public License is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * The Apache License v2.0 is available at
 * http://www.opensource.org/licenses/apache2.0.php
 *
 * You may elect to redistribute this code under either of these licenses.
 */
package org.jmqtt.core.codec;

import io.netty.buffer.ByteBuf;
import io.netty.handler.codec.CorruptedFrameException;
import io.netty.util.AttributeMap;
import org.jmqtt.core.constant.QosType;
import org.jmqtt.core.packet.UnsubscribePacket;
import org.jmqtt.core.util.MqttUtils;

import java.util.List;

/**
 * @author andrea
 */
class UnsubscribeDecoder extends DemuxDecoder {

    @Override
    void decode(AttributeMap ctx, ByteBuf in, List<Object> out) throws Exception {
        //Common decoding part
        in.resetReaderIndex();
        UnsubscribePacket message = new UnsubscribePacket();
        if (!decodeCommonHeader(message, 0x02, in)) {
            in.resetReaderIndex();
            return;
        }

        //check qos level
        if (message.getQos() != QosType.LEAST_ONE) {
            throw new CorruptedFrameException(
                    "Found an Unsubscribe message with qos other than LEAST_ONE, was: " + message.getQos());
        }

        int start = in.readerIndex();
        //read  messageIDs
        message.setPacketId(in.readUnsignedShort());
        int read = in.readerIndex() - start;
        while (read < message.getRemainingLength()) {
            String topicFilter = MqttUtils.decodeString(in);
            //check topic is at least one char [MQTT-4.7.3-1]
            if (topicFilter.length() == 0) {
                throw new CorruptedFrameException("Received an UNSUBSCRIBE with empty topic filter");
            }
            message.addTopicFilter(topicFilter);
            read = in.readerIndex() - start;
        }
        if (message.topicFilters().isEmpty()) {
            throw new CorruptedFrameException("unsubscribe MUST have got at least 1 topic");
        }
        out.add(message);
    }

}