kafka RecordsSend 源码

kafka RecordsSend 代码

文件路径：/clients/src/main/java/org/apache/kafka/common/record/RecordsSend.java

/*
 * 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.apache.kafka.common.record;

import org.apache.kafka.common.network.Send;
import org.apache.kafka.common.network.TransferableChannel;

import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;

public abstract class RecordsSend<T extends BaseRecords> implements Send {
    private static final ByteBuffer EMPTY_BYTE_BUFFER = ByteBuffer.allocate(0);

    private final T records;
    private final int maxBytesToWrite;
    private int remaining;
    private boolean pending = false;

    protected RecordsSend(T records, int maxBytesToWrite) {
        this.records = records;
        this.maxBytesToWrite = maxBytesToWrite;
        this.remaining = maxBytesToWrite;
    }

    @Override
    public boolean completed() {
        return remaining <= 0 && !pending;
    }

    @Override
    public final long writeTo(TransferableChannel channel) throws IOException {
        long written = 0;

        if (remaining > 0) {
            written = writeTo(channel, size() - remaining, remaining);
            if (written < 0)
                throw new EOFException("Wrote negative bytes to channel. This shouldn't happen.");
            remaining -= written;
        }

        pending = channel.hasPendingWrites();
        if (remaining <= 0 && pending)
            channel.write(EMPTY_BYTE_BUFFER);

        return written;
    }

    @Override
    public long size() {
        return maxBytesToWrite;
    }

    protected T records() {
        return records;
    }

    /**
     * Write records up to `remaining` bytes to `channel`. The implementation is allowed to be stateful. The contract
     * from the caller is that the first invocation will be with `previouslyWritten` equal to 0, and `remaining` equal to
     * the to maximum bytes we want to write the to `channel`. `previouslyWritten` and `remaining` will be adjusted
     * appropriately for every subsequent invocation. See {@link #writeTo} for example expected usage.
     * @param channel The channel to write to
     * @param previouslyWritten Bytes written in previous calls to {@link #writeTo(TransferableChannel, long, int)}; 0 if being called for the first time
     * @param remaining Number of bytes remaining to be written
     * @return The number of bytes actually written
     * @throws IOException For any IO errors
     */
    protected abstract long writeTo(TransferableChannel channel, long previouslyWritten, int remaining) throws IOException;
}

相关信息

kafka 源码目录

相关文章

kafka AbstractLegacyRecordBatch 源码

kafka AbstractRecordBatch 源码

kafka AbstractRecords 源码

kafka BaseRecords 源码

kafka ByteBufferLogInputStream 源码

kafka CompressionRatioEstimator 源码

kafka CompressionType 源码

kafka ControlRecordType 源码

kafka ControlRecordUtils 源码

kafka ConvertedRecords 源码