org.gridgain.grid.util.nio.GridNioServerBuffer Maven / Gradle / Ivy

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/* 
 Copyright (C) GridGain Systems. All Rights Reserved.
 
 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 org.gridgain.grid.util.nio;

import org.gridgain.grid.*;
import org.jetbrains.annotations.*;

import java.nio.*;

/**
 * NIO server buffer.
 */
public class GridNioServerBuffer {
    /** */
    private byte[] data;

    /** */
    private int cnt = -4;

    /** */
    private int msgSize;

    /**
     *
     */
    public void reset() {
        msgSize = 0;
        cnt = -4;
        data = null;
    }

    /**
     * Checks whether the byte array is filled.
     *
     * @return Flag indicating whether byte array is filled or not.
     */
    public boolean isFilled() {
        return cnt > 0 && cnt == msgSize;
    }

    /**
     * Get data withing the buffer.
     *
     * @return Data.
     */
    public byte[] data() {
        return data;
    }

    /**
     * @param buf Buffer.
     * @return Message bytes or {@code null} if message is not fully read yet.
     * @throws GridException If failed to parse message.
     */
    @Nullable public byte[] read(ByteBuffer buf) throws GridException {
        if (cnt < 0) {
            for (; cnt < 0 && buf.hasRemaining(); cnt++) {
                msgSize <<= 8;

                msgSize |= buf.get() & 0xFF;
            }

            if (cnt < 0)
                return null;

            // If count is 0 then message size should be inited.
            if (msgSize <= 0)
                throw new GridException("Invalid message size: " + msgSize);

            data = new byte[msgSize];
        }

        assert msgSize > 0;
        assert cnt >= 0;

        int remaining = buf.remaining();

        // If there are more bytes in buffer.
        if (remaining > 0) {
            int missing = msgSize - cnt;

            // Read only up to message size.
            if (missing > 0) {
                int len = missing < remaining ? missing : remaining;

                buf.get(data, cnt, len);

                cnt += len;
            }
        }

        if (cnt == msgSize) {
            byte[] data0 = data;

            reset();

            return data0;
        }
        else
            return null;
    }
}