Chelsea Salyards created ARTEMIS-4327:
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Summary: AMQBuffer.readNullableString() is returning null when
the buffer is not empty
Key: ARTEMIS-4327
URL: https://issues.apache.org/jira/browse/ARTEMIS-4327
Project: ActiveMQ Artemis
Issue Type: Bug
Components: ActiveMQ-Artemis-Native
Affects Versions: 2.19.1
Environment: Artemis client is
org.apache.activemq:artemis-core-client:2.19.1, Java code is using the Artemis
Core API.
Artemis server appears to be 2.28.0, and is running in a Docker container.
Reporter: Chelsea Salyards
Assignee: Clebert Suconic
*The Issue*
Either I do not understand the intended functionality of
AMQBuffer.readNullableString(), or it is not functioning correctly. Based on
the name, I assumed that it would return null if the buffer was empty, and if
it was not, it would return a string.
In my client code, I have the following:
ServerLocator locator = ActiveMQClient.createServerLocator(AMQ_BROKER_URL);
ClientSessionFactory sessionFactory = locator.createSessionFactory();
ClientSession session = sessionFactory.createSession();
session.start();
Client message = session.createMessage(true);
message.getBodyBuffer().writeString("test string");
logger.debug("Regular string: " + message.getDataBuffer().readString());
logger.debug("Nullable string: " +
message.getDataBuffer().readNullableString());
ClientProducer producer = session.createProducer("test-queue");
producer.send(message);
The first debug output, using readString() prints out the string "test string"
like I expect.
However, the second debug output prints null, but I expected it to print "test
string".
*Potential Cause*
I took a look at the message in the queue via the Artemis web console, and I
can see the bytes for the message body are as follows:
00 00 00 0b 00 0b 74 65 73 74 20 73 74 72 69 6e 67
I took a look at the Artemis client source code, and looking at the code for
ChannelBufferWrapper, an implementation of the ActiveMQBuffer class, I see that
readNullableString() is defined as the following:
activemq-artemis/artemis-commons/src/main/java/org/apache/activemq/artemis/core/buffers/impl/ChannelBufferWrapper.java
public String readNullableString() {
int b = buffer.readByte();
if (b == DataConstants.NULL) {
return null;
}
return readStringInternal();
}
So if I am reading this correctly, this seems to be saying that if the buffer
starts with the byte 00, it will return null, even if the buffer is not empty.
Am I reading this correctly? As shown in my example above, the message body
starts with byte 00.
Other details about the message, if it helps:
durable: true
protocol: CORE
type: default
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