/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.mina.example.tapedeck;
import java.nio.charset.Charset;
import java.util.LinkedList;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.filterchain.IoFilter.NextFilter;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.apache.mina.filter.codec.textline.LineDelimiter;
import org.apache.mina.filter.codec.textline.TextLineDecoder;
/**
* MINA {@link ProtocolDecoder} which decodes bytes into {@link Command}
* objects.
*
* @author The Apache MINA Project (dev@mina.apache.org)
* @version $Rev: 713125 $, $Date: 2008-11-11 20:32:26 +0100 (Tue, 11 Nov 2008) $
*/
public class CommandDecoder extends TextLineDecoder {
public CommandDecoder() {
super(Charset.forName("UTF8"), LineDelimiter.WINDOWS);
}
private Object parseCommand(String line) throws CommandSyntaxException {
String[] temp = line.split(" +", 2);
String cmd = temp[0].toLowerCase();
String arg = temp.length > 1 ? temp[1] : null;
if (LoadCommand.NAME.equals(cmd)) {
if (arg == null) {
throw new CommandSyntaxException("No tape number specified");
}
try {
return new LoadCommand(Integer.parseInt(arg));
} catch (NumberFormatException nfe) {
throw new CommandSyntaxException("Illegal tape number: " + arg);
}
} else if (PlayCommand.NAME.equals(cmd)) {
return new PlayCommand();
} else if (PauseCommand.NAME.equals(cmd)) {
return new PauseCommand();
} else if (StopCommand.NAME.equals(cmd)) {
return new StopCommand();
} else if (ListCommand.NAME.equals(cmd)) {
return new ListCommand();
} else if (EjectCommand.NAME.equals(cmd)) {
return new EjectCommand();
} else if (QuitCommand.NAME.equals(cmd)) {
return new QuitCommand();
} else if (InfoCommand.NAME.equals(cmd)) {
return new InfoCommand();
} else if (UserCommand.NAME.equals(cmd)) {
if (arg == null) {
throw new CommandSyntaxException("No username specified");
}
return new UserCommand(arg);
} else if (PasswordCommand.NAME.equals(cmd)) {
if (arg == null) {
throw new CommandSyntaxException("No password specified");
}
return new PasswordCommand(arg);
}
throw new CommandSyntaxException("Unknown command: " + cmd);
}
@Override
public void decode(IoSession session, IoBuffer in, final ProtocolDecoderOutput out)
throws Exception {
final LinkedList<String> lines = new LinkedList<String>();
super.decode(session, in, new ProtocolDecoderOutput() {
public void write(Object message) {
lines.add((String) message);
}
public void flush(NextFilter nextFilter, IoSession session) {}
});
for (String s: lines) {
out.write(parseCommand(s));
}
}
}