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Framer.java
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Framer.java
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/*
* Copyright 2014-2016 CyberVision, Inc.
*
* 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 org.kaaproject.kaa.common.channels.protocols.kaatcp;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.ConnAck;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.Connect;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.Disconnect;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.KaaSync;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.MessageFactory;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.MessageType;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.MqttFrame;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.PingRequest;
import org.kaaproject.kaa.common.channels.protocols.kaatcp.messages.PingResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* Kaatcp Framer Class. Used to cut incoming byte stream into MQTT frames, and deliver frames to
* {@link MqttFramelistener}. Framer Class typically used from {@link MessageFactory} Class.
*
* @author Andrey Panasenko
*/
public class Framer {
public static final Logger LOG = LoggerFactory //NOSONAR
.getLogger(Framer.class);
/**
* Mqtt frame listeners list.
*/
private final List<MqttFramelistener> listeners;
/**
* Current processing frame.
*/
private MqttFrame currentFrame;
/**
* Default constructor.
*/
public Framer() {
listeners = new ArrayList<>();
}
/**
* Register Mqtt frame listener.
*
* @param listener MqttFramelistener
*/
public void registerFrameListener(MqttFramelistener listener) {
listeners.add(listener);
}
/**
* Process incoming bytes stream.
* Assumes that bytes is unprocessed bytes.
* In case of previous pushBytes() eaten not all bytes on next iterations
* bytes array should starts from unprocessed bytes.
*
* @param bytes byte[] to push
* @return number of bytes processed from this array.
* @throws KaaTcpProtocolException throws in case of protocol errors.
*/
public int pushBytes(byte[] bytes) throws KaaTcpProtocolException {
if (LOG.isTraceEnabled()) {
if (bytes != null) {
LOG.trace("Received bytes: {}", Arrays.toString(bytes));
}
}
int used = 0;
while (bytes.length > used) {
if (currentFrame == null) {
if ((bytes.length - used) >= 1) { // 1 bytes minimum header length
int intType = bytes[used] & 0xFF;
currentFrame = getFrameByType((byte) (intType >> 4));
++used;
} else {
break;
}
}
used += currentFrame.push(bytes, used);
if (currentFrame.decodeComplete()) {
callListeners(currentFrame.upgradeFrame());
currentFrame = null;
}
}
return used;
}
/**
* Notify all listeners on new Frame.
*/
private void callListeners(MqttFrame frame) {
for (MqttFramelistener listener : listeners) {
listener.onMqttFrame(frame);
}
}
/**
* Creates specific Kaatcp message by MessageType.
*
* @param type - MessageType of mqttFrame
* @return mqttFrame
* @throws KaaTcpProtocolException if specified type is unsupported
*/
private MqttFrame getFrameByType(byte type) throws KaaTcpProtocolException {
MqttFrame frame = null;
if (type == MessageType.CONNACK.getType()) {
frame = new ConnAck();
} else if (type == MessageType.CONNECT.getType()) {
frame = new Connect();
} else if (type == MessageType.DISCONNECT.getType()) {
frame = new Disconnect();
} else if (type == MessageType.KAASYNC.getType()) {
frame = new KaaSync();
} else if (type == MessageType.PINGREQ.getType()) {
frame = new PingRequest();
} else if (type == MessageType.PINGRESP.getType()) {
frame = new PingResponse();
} else {
throw new KaaTcpProtocolException("Got incorrect messageType format " + type);
}
return frame;
}
/**
* Reset Framer state by dropping currentFrame.
*/
public void flush() {
currentFrame = null;
}
}