com.spotify.netty4.handler.codec.zmtp.ZMTPMessageDecoder.java Source code

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Here is the source code for com.spotify.netty4.handler.codec.zmtp.ZMTPMessageDecoder.java

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/*
 * Copyright (c) 2012-2015 Spotify AB
 *
 * 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.spotify.netty4.handler.codec.zmtp;

import java.util.ArrayList;
import java.util.List;

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

public class ZMTPMessageDecoder implements ZMTPDecoder {

    public static final Factory FACTORY = new Factory() {
        @Override
        public ZMTPDecoder decoder(final ZMTPSession session) {
            return new ZMTPMessageDecoder();
        }
    };

    private static final ByteBuf DELIMITER = Unpooled.EMPTY_BUFFER;

    private final List<ByteBuf> frames = new ArrayList<ByteBuf>();
    private int frameLength;

    /**
     * Reset parser in preparation for the next message.
     */
    private void reset() {
        frames.clear();
        frameLength = 0;
    }

    @Override
    public void header(final ChannelHandlerContext ctx, final long length, final boolean more,
            final List<Object> out) {
        frameLength = (int) length;
    }

    @Override
    public void content(final ChannelHandlerContext ctx, final ByteBuf data, final List<Object> out) {
        // Wait for more data?
        if (data.readableBytes() < frameLength) {
            return;
        }

        if (frameLength == 0) {
            frames.add(DELIMITER);
            return;
        }

        final ByteBuf frame = data.readSlice(frameLength);
        frame.retain();
        frames.add(frame);
    }

    @Override
    public void finish(final ChannelHandlerContext ctx, final List<Object> out) {
        final ZMTPMessage message = ZMTPMessage.from(frames);
        reset();
        out.add(message);
    }

    @Override
    public void close() {
        for (final ByteBuf frame : frames) {
            frame.release();
        }
        frames.clear();
    }
}