ByteAppender.java

package com.gmail.woodyc40.common.protocol;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;

import javax.annotation.concurrent.ThreadSafe;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

/**
 * Wraps a bytebuffer which is used by the pipeline internally to send or decode bytes
 *
 * <p>Each segment is written individually</p>
 *
 * @author Pierre C
 */
@ThreadSafe
public class ByteAppender {
    /** The underlying bytebuf to append to */
    private final ConcurrentLinkedQueue<ByteBuf> bufs = new ConcurrentLinkedQueue<>();

    /**
     * Creates a new byte appender
     *
     * @param buf the buffer to wrap
     */
    private ByteAppender(ByteBuf buf) {
        bufs.add(buf);
    }

    /**
     * Wraps a bytebuf with a new appender
     *
     * @param buf the buffer to wrap
     * @return the new byte appender
     */
    public static ByteAppender wrap(ByteBuf buf) {
        return new ByteAppender(buf);
    }

    /**
     * Creates a new empty byte appender
     *
     * @return the new byte appender
     */
    public static ByteAppender empty() {
        return wrap(Unpooled.directBuffer());
    }

    /**
     * Separates the last byte entries and creates a new entry for subsequent bytes
     */
    public void segment() {
        bufs.add(Unpooled.directBuffer());
    }

    //////////////////////////////// APPENDING ////////////////////////////////

    /**
     * Appends a byte array to the buffer
     *
     * @param bytes the bytes to append
     */
    public void append(byte[] bytes) {
        bufs.peek().writeBytes(bytes);
    }

    /**
     * Appends a byte to the buffer
     *
     * @param by the byte to append
     */
    public void append(byte by) {
        bufs.peek().writeByte(by);
    }

    /**
     * Appends a byte buffer to the buffer
     *
     * @param buf the bytes to append
     */
    public void append(ByteBuf buf) {
        bufs.peek().writeBytes(buf);
    }

    /**
     * Appends a byte array to the buffer
     *
     * @param stream the bytes to append
     */
    public void append(ByteArrayOutputStream stream) {
        bufs.peek().writeBytes(stream.toByteArray());
    }

    /**
     * Appends the btyes from the given appender to this appender
     *
     * @param appender the appender to grab the bytes from
     */
    public void append(ByteAppender appender) {
        for (ByteBuf byteBuf : appender.bufs) {
            segment();
            append(byteBuf);
        }
    }

    //////////////////////////////// WRITING TO ////////////////////////////////

    /**
     * Writes the buffer to another buffer
     *
     * @param buf the buffer to write to
     */
    public void writeTo(ByteBuf buf) {
        for (ByteBuf b : bufs) {
            buf.writeBytes(b);
        }
    }

    /**
     * Writes the buffer to the stream
     *
     * @param stream the stream to write to
     */
    public void writeTo(ByteArrayOutputStream stream) {
        try {
            for (ByteBuf b : bufs) {
                stream.write(b.array());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * Writes and flushes the buffer's array to the channel
     *
     * @param ctx the channel to write to
     */
    public void writeTo(Channel ctx) {
        for (ByteBuf b : bufs) {
            ctx.writeAndFlush(b.array());
        }
    }

    //////////////////////////////// COPYING ////////////////////////////////

    /**
     * Returns the original internal buffer (non-array)
     *
     * @return the original buffer that was wrapped
     */
    public Queue<ByteBuf> wrapped() {
        return bufs;
    }

    /**
     * Copies the internal bytes to an array
     *
     * @return the copy of the byte array
     */
    public byte[] copy() {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        writeTo(stream);
        return stream.toByteArray();
    }
}