javax.management.remote.message.HandshakeBeginMessage Maven / Gradle / Ivy

/*
 * @(#)file      HandshakeBeginMessage.java
 * @(#)author    Sun Microsystems, Inc.
 * @(#)version   1.17
 * @(#)lastedit  07/03/08
 * @(#)build     @BUILD_TAG_PLACEHOLDER@
 *
 * 
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package javax.management.remote.message;

/**
 * Handshake begin message exchanged between the
 * server and the client.
 *
 * First of all, when the connection between the client and the
 * server is established the server sends this message to the client
 * with all the server's supported profiles and the server version of
 * the JMXMP protocol.
 *
 * The first thing the client does is to compare the version of the JMXMP
 * protocol supported by the server against the version supported by the
 * client. As a result of this comparison the following things can happen:
 * 

 * Both versions are equal, in which case the client continues with the
 *     profiles' negotiation.
 * The client version is greater than the server version and:
 *     
 *     The client can work with a lower version that matches the
 *         server's version, in which case it switches to the server's version
 *         and continues with the profiles' negotiation.
 *     The client cannot work with a lower version that matches the server's
 *         version, in which case it sends a
 *         {@link HandshakeErrorMessage HandshakeErrorMessage} and closes the
 *         connection.
 *     
 * The server version is greater than the client version so the client sends
 *     a {@link VersionMessage VersionMessage} specifying the client version
 *     and:
 *     
 *     The server can work with a lower version that matches the client's
 *         version, in which case it sends a
 *         {@link VersionMessage VersionMessage}
 *         specifying the client's version. Upon reception of this message the
 *         client continues with the profiles' negotiation.
 *     The server cannot work with a lower version that matches the client's
 *         version, in which case it sends a
 *         {@link HandshakeErrorMessage HandshakeErrorMessage} and closes the
 *         connection. Upon reception of this message the client should close
 *         the connection immediately.
 *     
 * 
 *
 * Once the JMXMP protocol versions to use have been negotiated,
 * the client and the server start the profile negotiation phase. The
 * server's supported profiles are configured by specifying the
 * jmx.remote.profiles property in the environment map
 * passed into the {@link javax.management.remote.JMXConnectorServer
 * JMXConnectorServer}.  Upon reception of the {@link
 * HandshakeBeginMessage HandshakeBeginMessage} the client verifies
 * that the profiles it wants to use, namely the ones specified through
 * the jmx.remote.profiles property in the environment
 * map passed into the {@link javax.management.remote.JMXConnector
 * JMXConnector} are all present in the server's supported profile
 * list. If false, the client sends a {@link HandshakeErrorMessage
 * HandshakeErrorMessage} to the server and closes
 * the connection. Otherwise, the client starts exchanging profile messages
 * with the server for the selected profiles following the order specified in
 * the client's profile list.  Once the
 * profile exchanges between the client and the server are completed
 * the client sends a {@link HandshakeEndMessage HandshakeEndMessage}
 * to notify the server that the handshake exchanges have been
 * successfully completed with regards to the client. Then the server
 * verifies that the negotiated profiles do not compromise the server's minimum
 * required security level and if the server agrees it sends
 * a {@link HandshakeEndMessage HandshakeEndMessage} to notify the
 * client that the handshake exchanges have been successfully
 * completed with regards to the server. If the server does not agree
 * on the negotiated profiles it sends a {@link HandshakeErrorMessage
 * HandshakeErrorMessage} to the client and closes the connection.
 *
 * 
If an error is encountered at any time, either on the client or
 * the server side, either peer can then send an {@link
 * HandshakeErrorMessage indication} as to why the operation failed.
 *
 * The server's supported profiles contained in this message are
 * formatted as a space-separated list.
 *
 * The server's JMXMP
 * protocol version describes the version of the JMXMP protocol
 * supported by the server.
 */
public class HandshakeBeginMessage implements Message {

    private static final long serialVersionUID = 293823783004524086L;

    /**
     * @serial The space-separated list of the server's supported 
     *         profile names.
     * @see #getProfiles()
     **/
    private String profiles;

    /**
     * @serial The server version of the JMXMP protocol.
     * @see #getVersion()
     **/
    private String version;

    /**
     * Constructs a new HandshakeBeginMessage with the space-separated list
     * of server's supported profile names and the server version of the JMXMP
     * protocol.
     *
     * @param profiles a space-separated list of the server's
     * supported profile names.
     * @param version the server's version of the JMXMP protocol.
     */
    public HandshakeBeginMessage(String profiles, String version) {
        this.profiles = profiles;
        this.version = version;
    }

    /**
     * A space-separated list containing the server's supported profile names.
     * @return The space-separated list of the server's supported 
     *         profile names.
     */
    public String getProfiles() {
        return profiles;
    }

    /**
     * The version of the JMXMP protocol supported by the server.
     * @return The server version of the JMXMP protocol.
     */
    public String getVersion() {
        return version;
    }
}