- * In addition to the replies listed at the type comment of each specific
- * command the node can always send the following messages:
- * ProtocolError (if this library screws up),
- * CloseConnectionDuplicateClientName (if a client with the same
- * name of the {@link de.todesbaum.util.freenet.fcp2.Connection} connects). So
- * when receiving messages from the node you should always be prepared for
- * something you did not expect.
- *
- * @author David Roden <droden@gmail.com>
- * @version $Id$
- */
-public abstract class Command {
-
- /** The line feed sequence used by the library. */
- protected static final String LINEFEED = "\r\n";
-
- /**
- * The name of the command. The name is sent to the node so it can not be
- * chosen arbitrarily!
- */
- private final String commandName;
-
- /**
- * The identifier of the command. This identifier is used to identify
- * replies that are caused by a command.
- */
- private final String identifier;
-
- /**
- * Creates a new command with the specified name and identifier.
- *
- * @param name
- * The name of the command
- * @param identifier
- * The identifier of the command
- */
- public Command(String name, String identifier) {
- this.commandName = name;
- this.identifier = identifier;
- }
-
- /**
- * Returns the name of this command.
- *
- * @return The name of this command
- */
- public String getCommandName() {
- return commandName;
- }
-
- /**
- * Return the identifier of this command.
- *
- * @return The identifier of this command
- */
- public String getIdentifier() {
- return identifier;
- }
-
- /**
- * Writes all parameters to the specified writer.
- *
- * NOTE: Subclasses of Command must call
- * super.write(writer) before or after writing their own
- * parameters!
- *
- * @param writer
- * The stream to write the parameters to
- * @throws IOException
- * if an I/O error occurs
- */
- protected void write(Writer writer) throws IOException {
- if (identifier != null)
- writer.write("Identifier=" + identifier + LINEFEED);
- }
-
- /**
- * Returns whether this command has payload to send after the message.
- * Subclasses need to return true here if they need to send
- * payload after the message.
- *
- * @return true if this command has payload to send,
- * false otherwise
- */
- protected boolean hasPayload() {
- return false;
- }
-
- /**
- * Returns the payload of this command as an {@link InputStream}. This
- * method is never called if {@link #hasPayload()} returns
- * false.
- *
- * @return The payload of this command
- */
- protected InputStream getPayload() {
- return null;
- }
-
- /**
- * Returns the length of the payload. This method is never called if
- * {@link #hasPayload()} returns false.
- *
- * @return The length of the payload
- */
- protected long getPayloadLength() {
- return -1;
- }
-
-}