Java Code Examples for org.apache.kafka.common.header.Headers#lastHeader()

/**
 * Gets the message type from the headers.  Throws if not found.
 *
 * @param headers the headers
 */
@SuppressWarnings("unchecked")
protected Class<T> getMessageType(Headers headers) {
    Header header = headers.lastHeader(JsonSchemaSerDeConstants.HEADER_MSG_TYPE);
    if (header == null) {
        throw new RuntimeException("Message Type not found in headers.");
    }
    String msgTypeName = IoUtil.toString(header.value());
    
    try {
        return (Class<T>) Thread.currentThread().getContextClassLoader().loadClass(msgTypeName);
    } catch (ClassNotFoundException ignored) {
    }
    try {
        return (Class<T>) Class.forName(msgTypeName);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}
 

@SuppressWarnings("unchecked")
@Nullable
private Map<String, String> decodeJsonTypes(Headers source) {
	Map<String, String> types = null;
	Header jsonTypes = source.lastHeader(JSON_TYPES);
	if (jsonTypes != null) {
		ObjectMapper headerObjectMapper = getObjectMapper();
		try {
			types = headerObjectMapper.readValue(jsonTypes.value(), Map.class);
		}
		catch (IOException e) {
			logger.error(e, () -> "Could not decode json types: " + new String(jsonTypes.value()));
		}
	}
	return types;
}
 

/**
 * Gets the global id from the headers.  Returns null if not found.
 *
 * @param headers the headers
 */
protected Long getGlobalId(Headers headers) {
    Header header = headers.lastHeader(JsonSchemaSerDeConstants.HEADER_GLOBAL_ID);
    if (header == null) {
        return null;
    }
    return ByteBuffer.wrap(header.value()).getLong();
}
 

/**
 * Gets the artifact id from the headers.  Throws if not found.
 *
 * @param headers the headers
 */
protected String getArtifactId(Headers headers) {
    Header header = headers.lastHeader(JsonSchemaSerDeConstants.HEADER_ARTIFACT_ID);
    if (header == null) {
        throw new RuntimeException("ArtifactId not found in headers.");
    }
    return IoUtil.toString(header.value());
}
 

/**
 * Gets the artifact version from the headers.  Returns null if not found.
 *
 * @param headers the headers
 */
protected Integer getVersion(Headers headers) {
    Header header = headers.lastHeader(JsonSchemaSerDeConstants.HEADER_VERSION);
    if (header == null) {
        return null;
    }
    return ByteBuffer.wrap(header.value()).getInt();
}
 

/**
 * serialize data with encryption (if needed). Key reference will be looked for exclusively in the Kafka Header
 * {@link KafkaCryptoConstants#KEY_REF_HEADER}
 *
 * @param topic
 * @param headers
 * @param data
 * @return
 */
@Override
public byte[] serialize(String topic, Headers headers, T data) {
    byte[] serializedData = rawSerializer.serialize(topic, headers, data);
    if (serializedData == null) {
        return null;
    }
    Header keyReferenceHeader = headers.lastHeader(KEY_REF_HEADER);
    return encrypt(serializedData, keyReferenceHeader == null ? null : keyReferenceHeader.value());
}
 

public static String getParsedKafkaHeader(Headers headers, String key) {
    Header h = headers.lastHeader(key);
    if (h == null) {
        return null;
    }
    return new String(h.value(), StandardCharsets.UTF_8);
}
 

@Override
public Object deserialize(String topic, Headers headers, byte[] data) {
    if (headers != null) {
        final Header header = headers.lastHeader(isKey ? keySchemaVersionIdHeaderName : valueSchemaVersionIdHeaderName);
        if (header != null) {
            return messageAndMetadataAvroDeserializer.deserialize(new MessageAndMetadata(header.value(), data), readerVersions.get(topic));
        }
    }
    return deserialize(topic, data);
}
 

private Optional<EventMessage<?>> buildMessage(Headers headers, SerializedMessage<?> message) {
    long timestamp = valueAsLong(headers, MESSAGE_TIMESTAMP);
    return headers.lastHeader(AGGREGATE_ID) != null
            ? buildDomainEvent(headers, message, timestamp)
            : buildEvent(message, timestamp);
}
 

private String lastHeader(final Headers headers, final String key) {
    final Header header = headers.lastHeader(key);
    return header != null ? toString(header.value()) : null;
}
 

@Nullable static String lastStringHeader(Headers headers, String key) {
  Header header = headers.lastHeader(key);
  if (header == null || header.value() == null) return null;
  return new String(header.value(), UTF_8);
}
 

@Nullable static String lastStringHeader(Headers headers, String key) {
  Header header = headers.lastHeader(key);
  if (header == null || header.value() == null) return null;
  return new String(header.value(), UTF_8);
}
 

/**
 * Return the {@code value} stored under a given {@code key} inside the {@link Headers}. In case of missing entry
 * {@code null} is returned.
 *
 * @param headers the Kafka {@code headers} to pull the value from
 * @param key     the key corresponding to the expected value
 * @return the value corresponding to the given {@code key} in the {@code headers}
 */
@SuppressWarnings("ConstantConditions") // Null check performed by `Assert.isTrue`
public static byte[] value(Headers headers, String key) {
    isTrue(headers != null, () -> "Headers may not be null");
    Header header = headers.lastHeader(key);
    return header != null ? header.value() : null;
}