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/*
* 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.requests;
import org.apache.kafka.common.errors.InvalidRequestException;
import org.apache.kafka.common.errors.UnsupportedVersionException;
import org.apache.kafka.common.message.RequestHeaderData;
import org.apache.kafka.common.protocol.ApiKeys;
import org.apache.kafka.common.protocol.ByteBufferAccessor;
import org.apache.kafka.common.protocol.ObjectSerializationCache;
import java.nio.ByteBuffer;
import java.util.Objects;
/**
* The header for a request in the Kafka protocol
*/
public class RequestHeader implements AbstractRequestResponse {
private final static int SIZE_NOT_INITIALIZED = -1;
private final RequestHeaderData data;
private final short headerVersion;
private int size = SIZE_NOT_INITIALIZED;
public RequestHeader(ApiKeys requestApiKey, short requestVersion, String clientId, int correlationId) {
this(new RequestHeaderData().
setRequestApiKey(requestApiKey.id).
setRequestApiVersion(requestVersion).
setClientId(clientId).
setCorrelationId(correlationId),
requestApiKey.requestHeaderVersion(requestVersion));
}
public RequestHeader(RequestHeaderData data, short headerVersion) {
this.data = data;
this.headerVersion = headerVersion;
}
public ApiKeys apiKey() {
return ApiKeys.forId(data.requestApiKey());
}
public short apiVersion() {
return data.requestApiVersion();
}
public short headerVersion() {
return headerVersion;
}
public String clientId() {
return data.clientId();
}
public int correlationId() {
return data.correlationId();
}
public RequestHeaderData data() {
return data;
}
// Visible for testing.
void write(ByteBuffer buffer, ObjectSerializationCache serializationCache) {
data.write(new ByteBufferAccessor(buffer), serializationCache, headerVersion);
}
/**
* Calculates the size of {@link RequestHeader} in bytes.
*
* This method to calculate size should be only when it is immediately followed by
* {@link #write(ByteBuffer, ObjectSerializationCache)} method call. In such cases, ObjectSerializationCache
* helps to avoid the serialization twice. In all other cases, {@link #size()} should be preferred instead.
*
* Calls to this method leads to calculation of size every time it is invoked. {@link #size()} should be preferred
* instead.
*
* Visible for testing.
*/
int size(ObjectSerializationCache serializationCache) {
this.size = data.size(serializationCache, headerVersion);
return size;
}
/**
* Returns the size of {@link RequestHeader} in bytes.
*
* Calls to this method are idempotent and inexpensive since it returns the cached value of size after the first
* invocation.
*/
public int size() {
if (this.size == SIZE_NOT_INITIALIZED) {
this.size = size(new ObjectSerializationCache());
}
return size;
}
public ResponseHeader toResponseHeader() {
return new ResponseHeader(data.correlationId(), apiKey().responseHeaderVersion(apiVersion()));
}
public static RequestHeader parse(ByteBuffer buffer) {
short apiKey = -1;
try {
// We derive the header version from the request api version, so we read that first.
// The request api version is part of `RequestHeaderData`, so we reset the buffer position after the read.
int bufferStartPositionForHeader = buffer.position();
apiKey = buffer.getShort();
short apiVersion = buffer.getShort();
short headerVersion = ApiKeys.forId(apiKey).requestHeaderVersion(apiVersion);
buffer.position(bufferStartPositionForHeader);
final RequestHeaderData headerData = new RequestHeaderData(new ByteBufferAccessor(buffer), headerVersion);
// Due to a quirk in the protocol, client ID is marked as nullable.
// However, we treat a null client ID as equivalent to an empty client ID.
if (headerData.clientId() == null) {
headerData.setClientId("");
}
final RequestHeader header = new RequestHeader(headerData, headerVersion);
// Size of header is calculated by the shift in the position of buffer's start position during parsing.
// Prior to parsing, the buffer's start position points to header data and after the parsing operation
// the buffer's start position points to api message. For more information on how the buffer is
// constructed, see RequestUtils#serialize()
header.size = Math.max(buffer.position() - bufferStartPositionForHeader, 0);
return header;
} catch (UnsupportedVersionException e) {
throw new InvalidRequestException("Unknown API key " + apiKey, e);
} catch (Throwable ex) {
throw new InvalidRequestException("Error parsing request header. Our best guess of the apiKey is: " +
apiKey, ex);
}
}
@Override
public String toString() {
return "RequestHeader(apiKey=" + apiKey() +
", apiVersion=" + apiVersion() +
", clientId=" + clientId() +
", correlationId=" + correlationId() +
", headerVersion=" + headerVersion +
")";
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
RequestHeader that = (RequestHeader) o;
return headerVersion == that.headerVersion &&
Objects.equals(data, that.data);
}
@Override
public int hashCode() {
return Objects.hash(data, headerVersion);
}
}
