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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;

import java.util.List;

/**
 * A decoder that splits the received {@link ByteBuf}s by one or more
 * delimiters.  It is particularly useful for decoding the frames which ends
 * with a delimiter such as {@link Delimiters#nulDelimiter() NUL} or
 * {@linkplain Delimiters#lineDelimiter() newline characters}.
 *
 * 
Predefined delimiters

 * 

 * {@link Delimiters} defines frequently used delimiters for convenience' sake.
 *
 * 
Specifying more than one delimiter

 * 

 * {@link DelimiterBasedFrameDecoder} allows you to specify more than one
 * delimiter.  If more than one delimiter is found in the buffer, it chooses
 * the delimiter which produces the shortest frame.  For example, if you have
 * the following data in the buffer:
 * 
 * +--------------+
 * | ABC\nDEF\r\n |
 * +--------------+
 * 

 * a {@link DelimiterBasedFrameDecoder}({@link Delimiters#lineDelimiter() Delimiters.lineDelimiter()})
 * will choose {@code '\n'} as the first delimiter and produce two frames:
 * 
 * +-----+-----+
 * | ABC | DEF |
 * +-----+-----+
 * 

 * rather than incorrectly choosing {@code '\r\n'} as the first delimiter:
 * 
 * +----------+
 * | ABC\nDEF |
 * +----------+
 * 

 */
public class DelimiterBasedFrameDecoder extends ByteToMessageDecoder {

    private final ByteBuf[] delimiters;
    private final int maxFrameLength;
    private final boolean stripDelimiter;
    private final boolean failFast;
    private boolean discardingTooLongFrame;
    private int tooLongFrameLength;
    /** Set only when decoding with "\n" and "\r\n" as the delimiter.  */
    private final LineBasedFrameDecoder lineBasedDecoder;

    /**
     * Creates a new instance.
     *
     * @param maxFrameLength  the maximum length of the decoded frame.
     *                        A {@link TooLongFrameException} is thrown if
     *                        the length of the frame exceeds this value.
     * @param delimiter  the delimiter
     */
    public DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf delimiter) {
        this(maxFrameLength, true, delimiter);
    }

    /**
     * Creates a new instance.
     *
     * @param maxFrameLength  the maximum length of the decoded frame.
     *                        A {@link TooLongFrameException} is thrown if
     *                        the length of the frame exceeds this value.
     * @param stripDelimiter  whether the decoded frame should strip out the
     *                        delimiter or not
     * @param delimiter  the delimiter
     */
    public DelimiterBasedFrameDecoder(
            int maxFrameLength, boolean stripDelimiter, ByteBuf delimiter) {
        this(maxFrameLength, stripDelimiter, true, delimiter);
    }

    /**
     * Creates a new instance.
     *
     * @param maxFrameLength  the maximum length of the decoded frame.
     *                        A {@link TooLongFrameException} is thrown if
     *                        the length of the frame exceeds this value.
     * @param stripDelimiter  whether the decoded frame should strip out the
     *                        delimiter or not
     * @param failFast  If true, a {@link TooLongFrameException} is
     *                  thrown as soon as the decoder notices the length of the
     *                  frame will exceed maxFrameLength regardless of
     *                  whether the entire frame has been read.
     *                  If false, a {@link TooLongFrameException} is
     *                  thrown after the entire frame that exceeds
     *                  maxFrameLength has been read.
     * @param delimiter  the delimiter
     */
    public DelimiterBasedFrameDecoder(
            int maxFrameLength, boolean stripDelimiter, boolean failFast,
            ByteBuf delimiter) {
        this(maxFrameLength, stripDelimiter, failFast, new ByteBuf[] {
                delimiter.slice(delimiter.readerIndex(), delimiter.readableBytes())});
    }

    /**
     * Creates a new instance.
     *
     * @param maxFrameLength  the maximum length of the decoded frame.
     *                        A {@link TooLongFrameException} is thrown if
     *                        the length of the frame exceeds this value.
     * @param delimiters  the delimiters
     */
    public DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf... delimiters) {
        this(maxFrameLength, true, delimiters);
    }

    /**
     * Creates a new instance.
     *
     * @param maxFrameLength  the maximum length of the decoded frame.
     *                        A {@link TooLongFrameException} is thrown if
     *                        the length of the frame exceeds this value.
     * @param stripDelimiter  whether the decoded frame should strip out the
     *                        delimiter or not
     * @param delimiters  the delimiters
     */
    public DelimiterBasedFrameDecoder(
            int maxFrameLength, boolean stripDelimiter, ByteBuf... delimiters) {
        this(maxFrameLength, stripDelimiter, true, delimiters);
    }

    /**
     * Creates a new instance.
     *
     * @param maxFrameLength  the maximum length of the decoded frame.
     *                        A {@link TooLongFrameException} is thrown if
     *                        the length of the frame exceeds this value.
     * @param stripDelimiter  whether the decoded frame should strip out the
     *                        delimiter or not
     * @param failFast  If true, a {@link TooLongFrameException} is
     *                  thrown as soon as the decoder notices the length of the
     *                  frame will exceed maxFrameLength regardless of
     *                  whether the entire frame has been read.
     *                  If false, a {@link TooLongFrameException} is
     *                  thrown after the entire frame that exceeds
     *                  maxFrameLength has been read.
     * @param delimiters  the delimiters
     */
    public DelimiterBasedFrameDecoder(
            int maxFrameLength, boolean stripDelimiter, boolean failFast, ByteBuf... delimiters) {
        validateMaxFrameLength(maxFrameLength);
        if (delimiters == null) {
            throw new NullPointerException("delimiters");
        }
        if (delimiters.length == 0) {
            throw new IllegalArgumentException("empty delimiters");
        }

        if (isLineBased(delimiters) && !isSubclass()) {
            lineBasedDecoder = new LineBasedFrameDecoder(maxFrameLength, stripDelimiter, failFast);
            this.delimiters = null;
        } else {
            this.delimiters = new ByteBuf[delimiters.length];
            for (int i = 0; i < delimiters.length; i ++) {
                ByteBuf d = delimiters[i];
                validateDelimiter(d);
                this.delimiters[i] = d.slice(d.readerIndex(), d.readableBytes());
            }
            lineBasedDecoder = null;
        }
        this.maxFrameLength = maxFrameLength;
        this.stripDelimiter = stripDelimiter;
        this.failFast = failFast;
    }

    /** Returns true if the delimiters are "\n" and "\r\n".  */
    private static boolean isLineBased(final ByteBuf[] delimiters) {
        if (delimiters.length != 2) {
            return false;
        }
        ByteBuf a = delimiters[0];
        ByteBuf b = delimiters[1];
        if (a.capacity() < b.capacity()) {
            a = delimiters[1];
            b = delimiters[0];
        }
        return a.capacity() == 2 && b.capacity() == 1
                && a.getByte(0) == '\r' && a.getByte(1) == '\n'
                && b.getByte(0) == '\n';
    }

    /**
     * Return {@code true} if the current instance is a subclass of DelimiterBasedFrameDecoder
     */
    private boolean isSubclass() {
        return getClass() != DelimiterBasedFrameDecoder.class;
    }

    @Override
    protected final void decode(ChannelHandlerContext ctx, ByteBuf in, List out) throws Exception {
        Object decoded = decode(ctx, in);
        if (decoded != null) {
            out.add(decoded);
        }
    }

    /**
     * Create a frame out of the {@link ByteBuf} and return it.
     *
     * @param   ctx             the {@link ChannelHandlerContext} which this {@link ByteToMessageDecoder} belongs to
     * @param   buffer          the {@link ByteBuf} from which to read data
     * @return  frame           the {@link ByteBuf} which represent the frame or {@code null} if no frame could
     *                          be created.
     */
    protected Object decode(ChannelHandlerContext ctx, ByteBuf buffer) throws Exception {
        if (lineBasedDecoder != null) {
            return lineBasedDecoder.decode(ctx, buffer);
        }
        // Try all delimiters and choose the delimiter which yields the shortest frame.
        int minFrameLength = Integer.MAX_VALUE;
        ByteBuf minDelim = null;
        for (ByteBuf delim: delimiters) {
            int frameLength = indexOf(buffer, delim);
            if (frameLength >= 0 && frameLength < minFrameLength) {
                minFrameLength = frameLength;
                minDelim = delim;
            }
        }

        if (minDelim != null) {
            int minDelimLength = minDelim.capacity();
            ByteBuf frame;

            if (discardingTooLongFrame) {
                // We've just finished discarding a very large frame.
                // Go back to the initial state.
                discardingTooLongFrame = false;
                buffer.skipBytes(minFrameLength + minDelimLength);

                int tooLongFrameLength = this.tooLongFrameLength;
                this.tooLongFrameLength = 0;
                if (!failFast) {
                    fail(tooLongFrameLength);
                }
                return null;
            }

            if (minFrameLength > maxFrameLength) {
                // Discard read frame.
                buffer.skipBytes(minFrameLength + minDelimLength);
                fail(minFrameLength);
                return null;
            }

            if (stripDelimiter) {
                frame = buffer.readSlice(minFrameLength);
                buffer.skipBytes(minDelimLength);
            } else {
                frame = buffer.readSlice(minFrameLength + minDelimLength);
            }

            return frame.retain();
        } else {
            if (!discardingTooLongFrame) {
                if (buffer.readableBytes() > maxFrameLength) {
                    // Discard the content of the buffer until a delimiter is found.
                    tooLongFrameLength = buffer.readableBytes();
                    buffer.skipBytes(buffer.readableBytes());
                    discardingTooLongFrame = true;
                    if (failFast) {
                        fail(tooLongFrameLength);
                    }
                }
            } else {
                // Still discarding the buffer since a delimiter is not found.
                tooLongFrameLength += buffer.readableBytes();
                buffer.skipBytes(buffer.readableBytes());
            }
            return null;
        }
    }

    private void fail(long frameLength) {
        if (frameLength > 0) {
            throw new TooLongFrameException(
                            "frame length exceeds " + maxFrameLength +
                            ": " + frameLength + " - discarded");
        } else {
            throw new TooLongFrameException(
                            "frame length exceeds " + maxFrameLength +
                            " - discarding");
        }
    }

    /**
     * Returns the number of bytes between the readerIndex of the haystack and
     * the first needle found in the haystack.  -1 is returned if no needle is
     * found in the haystack.
     */
    private static int indexOf(ByteBuf haystack, ByteBuf needle) {
        for (int i = haystack.readerIndex(); i < haystack.writerIndex(); i ++) {
            int haystackIndex = i;
            int needleIndex;
            for (needleIndex = 0; needleIndex < needle.capacity(); needleIndex ++) {
                if (haystack.getByte(haystackIndex) != needle.getByte(needleIndex)) {
                    break;
                } else {
                    haystackIndex ++;
                    if (haystackIndex == haystack.writerIndex() &&
                        needleIndex != needle.capacity() - 1) {
                        return -1;
                    }
                }
            }

            if (needleIndex == needle.capacity()) {
                // Found the needle from the haystack!
                return i - haystack.readerIndex();
            }
        }
        return -1;
    }

    private static void validateDelimiter(ByteBuf delimiter) {
        if (delimiter == null) {
            throw new NullPointerException("delimiter");
        }
        if (!delimiter.isReadable()) {
            throw new IllegalArgumentException("empty delimiter");
        }
    }

    private static void validateMaxFrameLength(int maxFrameLength) {
        if (maxFrameLength <= 0) {
            throw new IllegalArgumentException(
                    "maxFrameLength must be a positive integer: " +
                    maxFrameLength);
        }
    }
}
 















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