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@@ -414,6 +414,53 @@ transmit headers from any adapter that supports key-value metadata
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<div class="sect3">
<h4 id="_supplier"><a class="link" href="#_supplier">Supplier</a></h4>
<div class="paragraph">
<p>As you can see from the table above Supplier can be <em>reactive</em> - <code>Supplier&lt;Flux&lt;T&gt;&gt;</code>
or <em>imperative</em> - <code>Supplier&lt;T&gt;</code>. From the invocation standpoint this should make no difference
to the implementor of such Supplier. However, when used within frameworks
(e.g., <a href="https://spring.io/projects/spring-cloud-stream">Spring Cloud Stream</a>), Suppliers, especially reactive,
often used to represent the source of the stream, therefore they are invoked once to get the stream (e.g., Flux)
to which consumers can subscribe to. In other words such suppliers represent an equivalent of an <em>infinite stream</em>.
However, the same reactive suppliers can also represent <em>finite</em> stream(s) (e.g., result set on the polled JDBC data).
In those cases such reactive suppliers must be hooked up to some polling mechanism of the underlying framework.</p>
</div>
<div class="paragraph">
<p>To assist with that Spring Cloud Function provides a marker annotation
<code>org.springframework.cloud.function.context.PollableSupplier</code> to signal that such supplier produces a
finite stream and may need to be polled again. That said, it is important to understand that Spring Cloud Function itself
provides no behavior for this annotation.</p>
</div>
<div class="paragraph">
<p>In addition <code>PollableSupplier</code> annotation exposes a <em>splittable</em> attribute to signal that produced stream
needs to be split (see <a href="https://www.enterpriseintegrationpatterns.com/patterns/messaging/Sequencer.html">Splitter EIP</a>)</p>
</div>
<div class="paragraph">
<p>Here is the example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="highlightjs highlight"><code class="language-java hljs" data-lang="java">@PollableSupplier(splittable = true)
public Supplier&lt;Flux&lt;String&gt;&gt; someSupplier() {
return () -&gt; {
String v1 = String.valueOf(System.nanoTime());
String v2 = String.valueOf(System.nanoTime());
String v3 = String.valueOf(System.nanoTime());
return Flux.just(v1, v2, v3);
};
}</code></pre>
</div>
</div>
</div>
<div class="sect3">
<h4 id="_function"><a class="link" href="#_function">Function</a></h4>
<div class="paragraph">
<p>TBD</p>
</div>
</div>
<div class="sect3">
<h4 id="_consumer"><a class="link" href="#_consumer">Consumer</a></h4>
<div class="paragraph">
<p>Consumer is a little bit special because it has a <code>void</code> return type,
which implies blocking, at least potentially. Most likely you will not
@@ -424,6 +471,7 @@ function that returns a publisher, so that it can be subscribed to in
a controlled way.</p>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_function_component_scan"><a class="link" href="#_function_component_scan">Function Component Scan</a></h3>
<div class="paragraph">