Merge branch 'release-0.11'

[jSite.git] / src / main / java / de / todesbaum / util / freenet / fcp2 / Command.java

diff --git a/src/main/java/de/todesbaum/util/freenet/fcp2/Command.java b/src/main/java/de/todesbaum/util/freenet/fcp2/Command.java
new file mode 100644 (file)
index 0000000..63aaa9c
--- /dev/null
+++ b/src/main/java/de/todesbaum/util/freenet/fcp2/Command.java
@@ -0,0 +1,137 @@
+/*
+ * jSite - Command.java - Copyright © 2006–2012 David Roden
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+package de.todesbaum.util.freenet.fcp2;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.Writer;
+
+/**
+ * Abstract base class for all commands.
+ * <p>
+ * In addition to the replies listed at the type comment of each specific
+ * command the node can <strong>always</strong> send the following messages:
+ * <code>ProtocolError</code> (if this library screws up),
+ * <code>CloseConnectionDuplicateClientName</code> (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 &lt;droden@gmail.com&gt;
+ * @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.
+        * <p>
+        * <strong>NOTE:</strong> Subclasses of Command <strong>must</strong> call
+        * <code>super.write(writer)</code> 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 <code>true</code> here if they need to send
+        * payload after the message.
+        *
+        * @return <code>true</code> if this command has payload to send,
+        *         <code>false</code> 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
+        * <code>false</code>.
+        *
+        * @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 <code>false</code>.
+        *
+        * @return The length of the payload
+        */
+       protected long getPayloadLength() {
+               return -1;
+       }
+
+}