org.cloudata.core.commitlog.pipe.Message.java Source code

Introduction

Here is the source code for org.cloudata.core.commitlog.pipe.Message.java

Source

/**
 * 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.cloudata.core.commitlog.pipe;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

class Message {
    static final Log LOG = LogFactory.getLog(Message.class);

    static final int HEADER_SIZE = 16;
    static final byte[] MAGIC_KEY = new byte[] { 0xC, 0xA, 0xF, 0xE, 0xB, 0xA, 0xB, 0xE };

    ByteBuffer headerBuf;
    ByteBuffer buffer;
    int opCode;
    int length;
    boolean readingHeaderPhase;
    boolean writingHeaderPhase;

    int writtenPosition = 0;

    Message() {
        headerBuf = ByteBuffer.allocate(HEADER_SIZE);
        clear();
    }

    public void setMessage(int opCode, String msg) {
        headerBuf.clear();
        headerBuf.put(MAGIC_KEY);
        headerBuf.putInt(opCode);
        byte[] msgBuf = msg.getBytes();
        headerBuf.putInt(msgBuf.length);
        buffer = ByteBuffer.allocate(msgBuf.length);
        buffer.put(msgBuf);
        headerBuf.flip();
        buffer.flip();
    }

    public ByteBuffer getHeaderBuffer() {
        return headerBuf;
    }

    public ByteBuffer getBuffer() {
        return buffer;
    }

    public boolean write(SocketChannel channel) throws IOException {
        if (writingHeaderPhase) {
            ByteBuffer dupHeaderBuf = duplicate(headerBuf);
            dupHeaderBuf.position(writtenPosition);
            dupHeaderBuf.limit(headerBuf.capacity());
            channel.write(dupHeaderBuf);

            if (dupHeaderBuf.hasRemaining()) {
                writtenPosition = dupHeaderBuf.position();
                return false;
            }
            dupHeaderBuf.clear();
            writtenPosition = 0;
            writingHeaderPhase = false;
        }

        ByteBuffer dupBuffer = duplicate(buffer);
        dupBuffer.position(writtenPosition);
        dupBuffer.limit(buffer.capacity());
        channel.write(dupBuffer);

        if (dupBuffer.hasRemaining()) {
            writtenPosition = dupBuffer.position();
            return false;
        }

        writtenPosition = 0;
        writingHeaderPhase = true;
        dupBuffer.clear();
        return true;
    }

    public boolean read(SocketChannel channel) throws IOException {
        if (readingHeaderPhase) {
            if (channel.read(headerBuf) == -1) {
                throw new IOException("End of stream");
            }

            if (headerBuf.hasRemaining()) {
                return false;
            }

            decodeHeader();
            buffer = ByteBuffer.allocate(length);
            readingHeaderPhase = false;
        }

        if (channel.read(buffer) == -1) {
            throw new IOException("End of stream");
        }

        if (!buffer.hasRemaining()) {
            buffer.flip();
            readingHeaderPhase = true;
            return true;
        }

        return false;
    }

    private void decodeHeader() throws IOException {
        headerBuf.flip();

        if (hasValidHeader(headerBuf)) {
            headerBuf.position(MAGIC_KEY.length);

            opCode = headerBuf.getInt();
            length = headerBuf.getInt();
        } else {
            throw new IOException("Invalid connection with invalid header");
        }
    }

    private boolean hasValidHeader(ByteBuffer buf) {
        byte[] array = buf.array();

        for (int i = 0; i < MAGIC_KEY.length; i++) {
            if (array[i] != MAGIC_KEY[i]) {
                LOG.warn("Invalid header");
                return false;
            }
        }
        LOG.debug("Valid header");
        return true;
    }

    private ByteBuffer duplicate(ByteBuffer buf) {
        // LOG.debug("before pos : " + buf.position());
        // LOG.debug("before limit : " + buf.limit());

        ByteBuffer ret = buf.duplicate();

        if (ret.position() == ret.limit()) {
            ret.flip();
        }

        // LOG.debug("after pos : " + ret.position());
        // LOG.debug("after limit : " + ret.limit());

        return ret;
    }

    public void clear() {
        headerBuf.clear();
        buffer = null;
        readingHeaderPhase = true;
        writingHeaderPhase = true;
        writtenPosition = 0;
    }
}