kafka ProcessorRecordContext 源码

kafka ProcessorRecordContext 代码

文件路径：/streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorRecordContext.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.streams.processor.internals;

import org.apache.kafka.common.header.Header;
import org.apache.kafka.common.header.Headers;
import org.apache.kafka.common.header.internals.RecordHeader;
import org.apache.kafka.common.header.internals.RecordHeaders;
import org.apache.kafka.streams.processor.RecordContext;
import org.apache.kafka.streams.processor.api.RecordMetadata;

import java.nio.ByteBuffer;
import java.util.Objects;

import static java.nio.charset.StandardCharsets.UTF_8;
import static java.util.Objects.requireNonNull;
import static org.apache.kafka.common.utils.Utils.getNullableSizePrefixedArray;

public class ProcessorRecordContext implements RecordContext, RecordMetadata {

    private final long timestamp;
    private final long offset;
    private final String topic;
    private final int partition;
    private final Headers headers;

    public ProcessorRecordContext(final long timestamp,
                                  final long offset,
                                  final int partition,
                                  final String topic,
                                  final Headers headers) {
        this.timestamp = timestamp;
        this.offset = offset;
        this.topic = topic;
        this.partition = partition;
        this.headers = Objects.requireNonNull(headers);
    }

    @Override
    public long offset() {
        return offset;
    }

    @Override
    public long timestamp() {
        return timestamp;
    }

    @Override
    public String topic() {
        return topic;
    }

    @Override
    public int partition() {
        return partition;
    }

    @Override
    public Headers headers() {
        return headers;
    }

    public long residentMemorySizeEstimate() {
        long size = 0;
        size += Long.BYTES; // value.context.timestamp
        size += Long.BYTES; // value.context.offset
        if (topic != null) {
            size += topic.toCharArray().length;
        }
        size += Integer.BYTES; // partition
        for (final Header header : headers) {
            size += header.key().toCharArray().length;
            final byte[] value = header.value();
            if (value != null) {
                size += value.length;
            }
        }
        return size;
    }

    public byte[] serialize() {
        final byte[] topicBytes = topic.getBytes(UTF_8);
        final byte[][] headerKeysBytes;
        final byte[][] headerValuesBytes;

        int size = 0;
        size += Long.BYTES; // value.context.timestamp
        size += Long.BYTES; // value.context.offset
        size += Integer.BYTES; // size of topic
        size += topicBytes.length;
        size += Integer.BYTES; // partition
        size += Integer.BYTES; // number of headers

        final Header[] headers = this.headers.toArray();
        headerKeysBytes = new byte[headers.length][];
        headerValuesBytes = new byte[headers.length][];

        for (int i = 0; i < headers.length; i++) {
            size += 2 * Integer.BYTES; // sizes of key and value

            final byte[] keyBytes = headers[i].key().getBytes(UTF_8);
            size += keyBytes.length;
            final byte[] valueBytes = headers[i].value();
            if (valueBytes != null) {
                size += valueBytes.length;
            }

            headerKeysBytes[i] = keyBytes;
            headerValuesBytes[i] = valueBytes;
        }

        final ByteBuffer buffer = ByteBuffer.allocate(size);
        buffer.putLong(timestamp);
        buffer.putLong(offset);

        // not handling the null condition because we believe topic will never be null in cases where we serialize
        buffer.putInt(topicBytes.length);
        buffer.put(topicBytes);

        buffer.putInt(partition);
        buffer.putInt(headerKeysBytes.length);
        for (int i = 0; i < headerKeysBytes.length; i++) {
            buffer.putInt(headerKeysBytes[i].length);
            buffer.put(headerKeysBytes[i]);

            if (headerValuesBytes[i] != null) {
                buffer.putInt(headerValuesBytes[i].length);
                buffer.put(headerValuesBytes[i]);
            } else {
                buffer.putInt(-1);
            }
        }

        return buffer.array();
    }

    public static ProcessorRecordContext deserialize(final ByteBuffer buffer) {
        final long timestamp = buffer.getLong();
        final long offset = buffer.getLong();
        final String topic;
        {
            // we believe the topic will never be null when we serialize
            final byte[] topicBytes = requireNonNull(getNullableSizePrefixedArray(buffer));
            topic = new String(topicBytes, UTF_8);
        }
        final int partition = buffer.getInt();
        final int headerCount = buffer.getInt();
        final Headers headers;
        if (headerCount == -1) { // keep for backward compatibilty
            headers = new RecordHeaders();
        } else {
            final Header[] headerArr = new Header[headerCount];
            for (int i = 0; i < headerCount; i++) {
                final byte[] keyBytes = requireNonNull(getNullableSizePrefixedArray(buffer));
                final byte[] valueBytes = getNullableSizePrefixedArray(buffer);
                headerArr[i] = new RecordHeader(new String(keyBytes, UTF_8), valueBytes);
            }
            headers = new RecordHeaders(headerArr);
        }

        return new ProcessorRecordContext(timestamp, offset, partition, topic, headers);
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        final ProcessorRecordContext that = (ProcessorRecordContext) o;
        return timestamp == that.timestamp &&
            offset == that.offset &&
            partition == that.partition &&
            Objects.equals(topic, that.topic) &&
            Objects.equals(headers, that.headers);
    }

    /**
     * Equality is implemented in support of tests, *not* for use in Hash collections, since this class is mutable.
     */
    @Deprecated
    @Override
    public int hashCode() {
        throw new UnsupportedOperationException("ProcessorRecordContext is unsafe for use in Hash collections");
    }

    @Override
    public String toString() {
        return "ProcessorRecordContext{" +
            "topic='" + topic + '\'' +
            ", partition=" + partition +
            ", offset=" + offset +
            ", timestamp=" + timestamp +
            ", headers=" + headers +
            '}';
    }
}

相关信息

kafka 源码目录

相关文章

kafka AbstractProcessorContext 源码

kafka AbstractReadOnlyDecorator 源码

kafka AbstractReadWriteDecorator 源码

kafka AbstractTask 源码

kafka ActiveTaskCreator 源码

kafka ChangelogReader 源码

kafka ChangelogRecordDeserializationHelper 源码

kafka ChangelogRegister 源码

kafka ChangelogTopics 源码

kafka ClientUtils 源码