SendRsetCodec.java

/*
 * Licensed 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 com.ok2c.lightmtp.impl.protocol;

import java.io.IOException;
import java.nio.channels.SelectionKey;

import org.apache.http.nio.reactor.IOSession;
import org.apache.http.nio.reactor.SessionInputBuffer;
import org.apache.http.nio.reactor.SessionOutputBuffer;
import org.apache.http.util.Args;

import com.ok2c.lightmtp.SMTPCommand;
import com.ok2c.lightmtp.SMTPProtocolException;
import com.ok2c.lightmtp.SMTPReply;
import com.ok2c.lightmtp.message.SMTPCommandWriter;
import com.ok2c.lightmtp.message.SMTPMessageParser;
import com.ok2c.lightmtp.message.SMTPMessageWriter;
import com.ok2c.lightmtp.message.SMTPReplyParser;
import com.ok2c.lightmtp.protocol.ProtocolCodec;
import com.ok2c.lightmtp.protocol.ProtocolCodecs;

public class SendRsetCodec implements ProtocolCodec<ClientState> {

    enum CodecState {

        RSET_READY,
        RSET_RESPONSE_EXPECTED,
        COMPLETED

    }

    private final SMTPBuffers iobuffers;
    private final SMTPMessageParser<SMTPReply> parser;
    private final SMTPMessageWriter<SMTPCommand> writer;

    private CodecState codecState;

    public SendRsetCodec(final SMTPBuffers iobuffers) {
        super();
        Args.notNull(iobuffers, "IO buffers");
        this.iobuffers = iobuffers;
        this.parser = new SMTPReplyParser();
        this.writer = new SMTPCommandWriter();
        this.codecState = CodecState.RSET_READY;
    }

    @Override
    public void cleanUp() {
    }

    @Override
    public void reset(
            final IOSession iosession,
            final ClientState sessionState) throws IOException, SMTPProtocolException {
        this.parser.reset();
        this.writer.reset();
        this.codecState = CodecState.RSET_READY;

        iosession.setEvent(SelectionKey.OP_WRITE);
    }

    @Override
    public void produceData(
            final IOSession iosession,
            final ClientState sessionState) throws IOException, SMTPProtocolException {
        Args.notNull(iosession, "IO session");
        Args.notNull(sessionState, "Session state");

        SessionOutputBuffer buf = this.iobuffers.getOutbuf();

        switch (this.codecState) {
        case RSET_READY:
            SMTPCommand quit = new SMTPCommand("RSET");
            this.writer.write(quit, buf);
            this.codecState = CodecState.RSET_RESPONSE_EXPECTED;
            break;
        }

        if (buf.hasData()) {
            buf.flush(iosession.channel());
        }
        if (!buf.hasData()) {
            iosession.clearEvent(SelectionKey.OP_WRITE);
        }
    }

    @Override
    public void consumeData(
            final IOSession iosession,
            final ClientState sessionState) throws IOException, SMTPProtocolException {
        Args.notNull(iosession, "IO session");
        Args.notNull(sessionState, "Session state");

        SessionInputBuffer buf = this.iobuffers.getInbuf();

        int bytesRead = buf.fill(iosession.channel());
        SMTPReply reply = this.parser.parse(buf, bytesRead == -1);

        if (reply != null) {
            switch (this.codecState) {
            case RSET_RESPONSE_EXPECTED:
                sessionState.reset(null);
                sessionState.setReply(reply);
                this.codecState = CodecState.COMPLETED;
                break;
            default:
                throw new SMTPProtocolException("Unexpected reply: " + reply);
            }
        }
    }

    @Override
    public boolean isCompleted() {
        return this.codecState == CodecState.COMPLETED;
    }

    @Override
    public String next(
            final ProtocolCodecs<ClientState> codecs,
            final ClientState sessionState) {
        if (this.codecState == CodecState.COMPLETED) {
            if (sessionState.isTerminated()) {
                return ProtocolState.QUIT.name();
            }
            return ProtocolState.MAIL.name();
        } else {
            return null;
        }
    }

}