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//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
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package com.rabbitmq.client.amqp;
import java.time.Instant;
/** API to configure and create a {@link Consumer}. */
public interface ConsumerBuilder {
/**
* The queue to consume from.
*
* @param queue queue
* @return this builder instance
*/
ConsumerBuilder queue(String queue);
/**
* The callback for inbound messages.
*
* @param handler callback
* @return this builder instance
*/
ConsumerBuilder messageHandler(Consumer.MessageHandler handler);
/**
* The initial number credits to grant to the AMQP receiver.
*
* The default is 100.
*
* @param initialCredits number of initial credits
* @return this buidler instance
*/
ConsumerBuilder initialCredits(int initialCredits);
/**
* The consumer priority.
*
* @param priority consumer priority
* @return this builder instance
* @see Consumer Priorities
*/
ConsumerBuilder priority(int priority);
/**
* Add {@link com.rabbitmq.client.amqp.Resource.StateListener}s to the consumer.
*
* @param listeners listeners
* @return this builder instance
*/
ConsumerBuilder listeners(Resource.StateListener... listeners);
/**
* Options for a consumer consuming from a stream.
*
* @return stream options
* @see Streams
* @see Stream Consumers
*/
StreamOptions stream();
/**
* Set a listener to customize the subscription before the consumer is created (or recovered).
*
*
This callback is available for stream consumers.
*
* @param subscriptionListener subscription listener
* @return this builder instance
* @see SubscriptionListener
*/
ConsumerBuilder subscriptionListener(SubscriptionListener subscriptionListener);
/**
* Build the consumer.
*
* @return the configured consumer instance
*/
Consumer build();
/**
* Options for a consumer consuming from a stream.
*
* @see Streams
* @see Stream Consumers
*/
interface StreamOptions {
/**
* The offset to start consuming from.
*
* @param offset offset
* @return stream options
*/
StreamOptions offset(long offset);
/**
* A point in time to start consuming from.
*
*
Be aware consumers can receive messages published a bit before the specified timestamp.
*
* @param timestamp the timestamp
* @return stream options
*/
StreamOptions offset(Instant timestamp);
/**
* The offset to start consuming from.
*
* @param specification offset specification
* @return stream options
* @see StreamOffsetSpecification
*/
StreamOptions offset(StreamOffsetSpecification specification);
/**
* The offset to start consuming from as an interval string value.
*
*
Valid units are Y, M, D, h, m, s. Examples: 7D (7 days), 12h (12
* hours).
*
* @param interval the interval
* @return stream options
* @see Interval Syntax
*/
StreamOptions offset(String interval);
/**
* Filter values.
*
* @param values filter values
* @return stream options
* @see Stream Filtering
*/
StreamOptions filterValues(String... values);
/**
* Whether messages without a filter value should be sent.
*
*
Default is false (messages without a filter value are not sent).
*
* @param matchUnfiltered true to send messages without a filter value
* @return stream options
*/
StreamOptions filterMatchUnfiltered(boolean matchUnfiltered);
/**
* Return the consumer builder.
*
* @return the consumer builder
*/
ConsumerBuilder builder();
}
/** Offset specification to start consuming from. */
enum StreamOffsetSpecification {
/** Beginning of the stream. */
FIRST,
/** Last chunk of the stream. */
LAST,
/** Very end of the stream (new chunks). */
NEXT
}
/**
* Callback to modify a consumer subscription before the link creation.
*
*
This allows looking up the last processed offset for a stream consumer and attaching to this
* offset.
*/
interface SubscriptionListener {
/**
* Pre-subscription callback.
*
*
It is called before the link is created but also every time it recovers, e.g. after a
* connection failure.
*
*
Configuration set with {@link Context#streamOptions()} overrides the one set with {@link
* ConsumerBuilder#stream()}.
*
* @param context subscription context
*/
void preSubscribe(Context context);
/** Subscription context. */
interface Context {
/**
* Stream options, to set the offset to start consuming from.
*
*
Only the {@link StreamOptions} are accessible, the {@link StreamOptions#builder()}
* method returns null
*
* @return the stream options
* @see StreamOptions
*/
ConsumerBuilder.StreamOptions streamOptions();
}
}
}