org.apache.kafka.streams.processor.internals.ProcessorMetadata Maven / Gradle / Ivy
/*
* 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 java.io.ByteArrayOutputStream;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
/**
* ProcessorMetadata to be access and populated by processor node. This will be committed along with
* offset. This metadata is mainly for windowed aggregation processor to store last emitted timestamp
* for now. Therefore, the supported metadata value type is only Long which is timestamp type.
*/
public class ProcessorMetadata {
private final Map metadata;
// Whether metadata should be committed. We only need to commit if metadata is updated via
// put() or set explicitly
private boolean needsCommit;
public ProcessorMetadata() {
this(new HashMap<>());
}
public ProcessorMetadata(final Map metadata) {
this.metadata = metadata;
needsCommit = false;
}
public static ProcessorMetadata deserialize(final byte[] metaDataBytes) {
if (metaDataBytes == null || metaDataBytes.length == 0) {
return new ProcessorMetadata();
}
final ByteBuffer buffer = ByteBuffer.wrap(metaDataBytes);
final int entrySize = buffer.getInt();
final Map metadata = new HashMap<>(entrySize);
for (int i = 0; i < entrySize; i++) {
final int keySize = buffer.getInt();
final byte[] keyBytes = new byte[keySize];
buffer.get(keyBytes);
final Long value = buffer.getLong();
metadata.put(new String(keyBytes, StandardCharsets.UTF_8), value);
}
return new ProcessorMetadata(metadata);
}
public byte[] serialize() {
if (metadata.isEmpty()) {
return new byte[0];
}
final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
final byte[] mapSizeBytes = ByteBuffer.allocate(Integer.BYTES).putInt(metadata.size()).array();
outputStream.write(mapSizeBytes, 0, mapSizeBytes.length);
for (final Map.Entry entry : metadata.entrySet()) {
final byte[] keyBytes = entry.getKey().getBytes(StandardCharsets.UTF_8);
final int keyLen = keyBytes.length;
final byte[] buffer = ByteBuffer.allocate(Integer.BYTES + keyBytes.length + Long.BYTES)
.putInt(keyLen)
.put(keyBytes)
.putLong(entry.getValue())
.array();
outputStream.write(buffer, 0, buffer.length);
}
return outputStream.toByteArray();
}
public void put(final String key, final long value) {
metadata.put(key, value);
needsCommit = true;
}
public Long get(final String key) {
return metadata.get(key);
}
/**
* Merge with other metadata. Missing keys will be added. Existing key's value will be updated to
* max
* @param other Other metadata to be merged
*/
public void update(final ProcessorMetadata other) {
if (other == null) {
return;
}
for (final Map.Entry kv : other.metadata.entrySet()) {
final Long value = metadata.get(kv.getKey());
if (value == null || value < kv.getValue()) {
metadata.put(kv.getKey(), kv.getValue());
}
}
}
public void setNeedsCommit(final boolean needsCommit) {
this.needsCommit = needsCommit;
}
/**
* Whether metadata needs to be committed. It should be committed only if put is or
* {@link #setNeedsCommit} is called explicitly
*
* @return If metadata needs to be committed.
*/
public boolean needsCommit() {
return needsCommit;
}
@Override
public int hashCode() {
// needsCommit is not considered in hashCode or equals
return Objects.hashCode(metadata);
}
@Override
public boolean equals(final Object obj) {
if (obj == null || obj.getClass() != getClass()) {
return false;
}
if (this == obj) {
return true;
}
return metadata.equals(((ProcessorMetadata) obj).metadata);
}
}