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# Transport Protocols
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ActiveMQ supports multiple messaging protocols beyond standard JMS, including STOMP, AMQP, MQTT, and HTTP. This enables integration with diverse client platforms and messaging ecosystems.
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## Capabilities
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### STOMP Protocol Support
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Simple Text Oriented Messaging Protocol for interoperability with multiple platforms.
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```java { .api }
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/**
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 * STOMP protocol constants and command definitions
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 */
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public interface Stomp {
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    /** STOMP commands */
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    String CONNECT = "CONNECT";
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    String CONNECTED = "CONNECTED";
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    String SEND = "SEND";
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    String SUBSCRIBE = "SUBSCRIBE";
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    String UNSUBSCRIBE = "UNSUBSCRIBE";
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    String ACK = "ACK";
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    String NACK = "NACK";
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    String BEGIN = "BEGIN";
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    String COMMIT = "COMMIT";
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    String ABORT = "ABORT";
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    String DISCONNECT = "DISCONNECT";
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    String MESSAGE = "MESSAGE";
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    String RECEIPT = "RECEIPT";
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    String ERROR = "ERROR";
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    /** STOMP headers */
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    String DESTINATION = "destination";
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    String MESSAGE_ID = "message-id";
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    String SUBSCRIPTION = "subscription";
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    String RECEIPT_REQUESTED = "receipt";
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    String TRANSACTION = "transaction";
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    String ACK_MODE = "ack";
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    String SELECTOR = "selector";
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    String USER_ID = "login";
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    String PASSWORD = "passcode";
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    String CLIENT_ID = "client-id";
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    /** Message transformation headers */
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    String TRANSFORMATION = "transformation";
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    String TRANSFORMATION_JSON = "jms-json";
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    String TRANSFORMATION_XML = "jms-xml";
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    String TRANSFORMATION_OBJECT_JSON = "jms-object-json";
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    String TRANSFORMATION_OBJECT_XML = "jms-object-xml";
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    String TRANSFORMATION_MAP_JSON = "jms-map-json";
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    String TRANSFORMATION_MAP_XML = "jms-map-xml";
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}
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/**
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 * STOMP transport implementation
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 */
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public class StompTransport extends TcpTransport {
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    public StompTransport(WireFormat wireFormat, Socket socket) throws IOException;
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    public StompTransport(WireFormat wireFormat, Socket socket, InitBuffer initBuffer) throws IOException;
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}
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/**
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 * STOMP wire format for message serialization
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 */
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public class StompWireFormat implements WireFormat {
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    /** Get maximum data length */
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    public int getMaxDataLength();
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    public void setMaxDataLength(int maxDataLength);
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    /** Get maximum frame size */
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    public long getMaxFrameSize();
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    public void setMaxFrameSize(long maxFrameSize);
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}
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/**
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 * STOMP protocol exception
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 */
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public class ProtocolException extends IOException {
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    public ProtocolException(String message);
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    public ProtocolException(String message, Throwable cause);
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}
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```
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### AMQP Protocol Support
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Advanced Message Queuing Protocol 1.0 support for enterprise messaging.
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```java { .api }
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/**
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 * AMQP transport implementation
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 */
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public class AmqpTransport extends TransportSupport {
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    public AmqpTransport(WireFormat wireFormat, Socket socket) throws IOException;
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    public AmqpTransport(WireFormat wireFormat, SSLSocket socket) throws IOException;
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}
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/**
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 * AMQP NIO SSL transport
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 */
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public class AmqpNioSslTransport extends AmqpNioTransport {
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    public AmqpNioSslTransport(WireFormat wireFormat, SocketChannel channel, 
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                               SSLEngine engine) throws IOException;
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}
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/**
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 * AMQP wire format implementation
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 */
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public class AmqpWireFormat implements WireFormat {
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    /** AMQP version constants */
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    public static final int DEFAULT_MAX_FRAME_SIZE = 1024 * 1024;
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    public static final String QUEUE_PREFIX = "queue://";
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    public static final String TOPIC_PREFIX = "topic://";
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}
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/**
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 * AMQP utilities and support functions
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 */
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public class AmqpSupport {
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    /** Convert JMS destination to AMQP address */
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    public static String toAddress(Destination destination);
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    /** Convert AMQP address to JMS destination */
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    public static Destination toDestination(String address);
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    /** Message property conversion */
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    public static Object convertProperty(Object value);
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}
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/**
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 * SASL authentication mechanism interface
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 */
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public interface SaslMechanism {
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    /** Get mechanism name */
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    String getName();
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    /** Create initial response */
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    byte[] getInitialResponse() throws SaslException;
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    /** Process challenge response */
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    byte[] getChallengeResponse(byte[] challenge) throws SaslException;
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    /** Check if authentication is complete */
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    boolean isComplete();
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}
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```
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### MQTT Protocol Support
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Message Queuing Telemetry Transport for IoT and lightweight messaging.
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```java { .api }
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/**
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 * MQTT transport implementation
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 */
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public class MQTTTransport extends TcpTransport {
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    public MQTTTransport(WireFormat wireFormat, Socket socket) throws IOException;
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    public MQTTTransport(WireFormat wireFormat, Socket socket, InitBuffer initBuffer) throws IOException;
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}
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/**
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 * MQTT NIO SSL transport
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 */
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public class MQTTNIOSSLTransport extends MQTTNIOTransport {
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    public MQTTNIOSSLTransport(WireFormat wireFormat, SocketChannel channel, 
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                               SSLEngine engine) throws IOException;
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}
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/**
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 * MQTT wire format for message serialization
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 */
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public class MQTTWireFormat implements WireFormat {
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    /** MQTT protocol version */
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    public void setVersion(int version);
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    public int getVersion();
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    /** Keep alive interval */
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    public void setKeepAlive(int keepAlive);
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    public int getKeepAlive();
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}
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/**
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 * MQTT subscription management
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 */
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public class MQTTSubscription {
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    /** Get topic filter */
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    public String getTopicFilter();
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    public void setTopicFilter(String topicFilter);
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    /** Get quality of service level */
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    public QoS getQoS();
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    public void setQoS(QoS qos);
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    /** MQTT QoS levels */
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    public enum QoS {
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        AT_MOST_ONCE(0),
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        AT_LEAST_ONCE(1),
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        EXACTLY_ONCE(2);
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        private final int value;
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        QoS(int value) { this.value = value; }
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        public int getValue() { return value; }
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    }
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}
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/**
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 * MQTT protocol exception
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 */
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public class MQTTProtocolException extends IOException {
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    public MQTTProtocolException(String message);
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    public MQTTProtocolException(String message, Throwable cause);
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}
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```
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### HTTP Transport Support
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HTTP tunneling and WebSocket support for web-based messaging.
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```java { .api }
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/**
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 * HTTP tunnel servlet for JMS over HTTP
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 */
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public class HttpTunnelServlet extends HttpServlet {
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    /** Handle HTTP GET requests */
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    protected void doGet(HttpServletRequest request, HttpServletResponse response) 
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        throws ServletException, IOException;
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    /** Handle HTTP POST requests */
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    protected void doPost(HttpServletRequest request, HttpServletResponse response) 
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        throws ServletException, IOException;
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    /** Configure tunnel parameters */
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    public void setMaxReadTimeoutMillis(long maxReadTimeoutMillis);
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    public long getMaxReadTimeoutMillis();
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}
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/**
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 * HTTP client transport implementation
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 */
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public class HttpClientTransport extends HttpTransportSupport {
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    public HttpClientTransport(TextWireFormat wireFormat, URI uri) throws IOException;
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    public HttpClientTransport(TextWireFormat wireFormat, URI uri, HttpClient httpClient) throws IOException;
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}
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/**
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 * HTTP transport server
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 */
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public class HttpTransportServer extends TransportServerSupport {
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    /** Set HTTP server configuration */
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    public void setHttpServer(Server httpServer);
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    public Server getHttpServer();
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    /** Bind to address */
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    public void bind() throws Exception;
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    /** Start HTTP server */
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    public void start() throws Exception;
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    /** Stop HTTP server */
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    public void stop() throws Exception;
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}
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/**
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 * HTTP discovery agent for broker discovery
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public class HTTPDiscoveryAgent extends DiscoveryAgentSupport {
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    /** Set registry URL */
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    public void setRegistryURL(String registryURL);
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    public String getRegistryURL();
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    /** Start discovery */
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    public void start() throws Exception;
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    /** Stop discovery */
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    public void stop() throws Exception;
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    /** Advertise service */
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    public void serviceFailed(DiscoveryEvent event) throws IOException;
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    public void serviceAdded(DiscoveryEvent event);
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    public void serviceRemoved(DiscoveryEvent event);
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}
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```
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**Usage Examples:**
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```java
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// STOMP transport configuration
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BrokerService broker = new BrokerService();
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broker.addConnector("stomp://localhost:61613");
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// AMQP transport
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broker.addConnector("amqp://localhost:5672");
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// MQTT transport  
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broker.addConnector("mqtt://localhost:1883");
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// HTTP transport
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broker.addConnector("http://localhost:8080");
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// Multiple transports with SSL
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broker.addConnector("stomp+ssl://localhost:61614");
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broker.addConnector("mqtt+ssl://localhost:8883");
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// Auto-detection transport (detects protocol automatically)
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broker.addConnector("auto://localhost:5555");
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```
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## Types
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```java { .api }
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/**
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 * Wire format interface for protocol serialization
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 */
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public interface WireFormat {
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    /** Marshal object to byte array */
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    ByteSequence marshal(Object command) throws IOException;
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    /** Unmarshal byte array to object */
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    Object unmarshal(ByteSequence packet) throws IOException;
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    /** Set version */
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    void setVersion(int version);
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    int getVersion();
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}
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/**
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 * Text-based wire format for HTTP/WebSocket
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 */
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public interface TextWireFormat extends WireFormat {
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    /** Marshal to text */
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    String marshalText(Object command) throws IOException;
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    /** Unmarshal from text */
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    Object unmarshalText(String text) throws IOException;
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}
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/**
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 * Discovery event for service discovery
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 */
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public class DiscoveryEvent {
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    /** Get service name */
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    public String getServiceName();
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    /** Get service URI */
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    public URI getUri();
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    /** Check if service failed */
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    public boolean isFailed();
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}
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```