INT-3327: Add IntegrationConverter Annotation

JIRA: https://jira.spring.io/browse/INT-3327

INT-3327: Addressing PR comments

Polishing

src/reference/docbook/endpoint.xml

@@ -588,10 +588,12 @@ any transaction configuration essentially allowing you to enhance the behavior o
       In this scenario we need to perform type conversion. Spring Integration provides a convenient way for registering type
       converters (using the Spring 3.x ConversionService) within its own instance of a conversion service bean named
       <emphasis>integrationConversionService</emphasis>.
-      That bean is automatically created as soon as the first converter is defined using the Spring Integration namespace support.
+      That bean is automatically created as soon as the first converter is defined using the Spring Integration infrastructure.
 
       To register a Converter all you need is to implement
-      <interfacename>org.springframework.core.convert.converter.Converter</interfacename> and define it via
+      <interfacename>org.springframework.core.convert.converter.Converter</interfacename>,
+		<interfacename>org.springframework.core.convert.converter.GenericConverter</interfacename> or
+		<interfacename>org.springframework.core.convert.converter.ConverterFactory</interfacename> and define it via
       convenient namespace support:
       <programlisting language="xml"><![CDATA[<int:converter ref="sampleConverter"/>
 
@@ -602,6 +604,31 @@ any transaction configuration essentially allowing you to enhance the behavior o
     <bean class="o.s.i.config.xml.ConverterParserTests$TestConverter3"/>
 </int:converter>]]></programlisting>
      </para>
+	 <para>
+		 Starting with <emphasis>Spring Integration 4.0</emphasis>, the above configuration is available using annotations:
+		 <programlisting language="java"><![CDATA[@Component
+@IntegrationConverter
+public class TestConverter implements Converter<Boolean, Number> {
+
+	public Number convert(Boolean source) {
+		return source ? 1 : 0;
+	}
+
+}]]></programlisting>
+
+	or as a <code>@Configuration</code> part:
+	<programlisting language="java"><![CDATA[@Configuration
+@EnableIntegration
+public class ContextConfiguration {
+
+	@Bean
+	@IntegrationConverter
+	public SerializingConverter serializingConverter() {
+		return new SerializingConverter();
+	}
+
+}]]></programlisting>
+	 </para>
      <important>
          <para>
              When configuring an <emphasis>Application Context</emphasis>, the

src/reference/docbook/overview.xml

@@ -368,6 +368,15 @@
 		on <classname>@Bean</classname> methods within <classname>@Configuration</classname> classes. In either case,
 		the bean <emphasis role="bold">must</emphasis> be a <interfacename>ChannelInterceptor</interfacename>.
 	</para>
+	  <para>
+		  The <classname>@IntegrationConverter</classname> annotation has been introduced to
+		  mark <interfacename>Converter</interfacename>, <interfacename>GenericConverter</interfacename> or
+		  <interfacename>ConverterFactory</interfacename> beans as candidate converters for <code>integrationConversionService</code>.
+		  This annotation is an analogue of the <code>&lt;int:converter&gt;</code> xml element
+		  (see <xref linkend="payload-type-conversion"/>). <code>@IntegrationConverter</code> annotations
+		  can be placed at the class level (with a <classname>@Component</classname> stereotype annotation), or
+		  on <classname>@Bean</classname> methods within <classname>@Configuration</classname> classes.
+	  </para>
   </section>
 
 </chapter>

src/reference/docbook/whats-new.xml

@@ -56,7 +56,7 @@
 			<title>@MessagingGateway</title>
 			<para>
 				Messaging gateway interfaces can now be configured with the <code>@MessagingGateway</code> annotation.
-				It is an analogue of the <code>&lt;gateway/&gt;</code> xml element.
+				It is an analogue of the <code>&lt;int:gateway/&gt;</code> xml element.
 				For more information, see <xref linkend="messaging-gateway-annotation"/>.
 			</para>
 		</section>
@@ -68,7 +68,7 @@
 				Spring Integration infrastructure beans to be configured using Spring Boot's
 				<code>@EnableAutoConfiguration</code>.
 				For more information see
-				<ulink url="http://projects.spring.io/spring-boot/docs/spring-boot-autoconfigure/README.html"
+				<ulink url="http://docs.spring.io/spring-boot/docs/current/reference/html/using-boot-auto-configuration.html"
 						>Spring Boot - AutoConfigure</ulink>.
 			</para>
 		</section>
@@ -80,6 +80,14 @@
 				For more information, see <xref linkend="enable-integration"/>.
 			</para>
 		</section>
+		<section id="4.0-integration-converter">
+			<title>@IntegrationConverter</title>
+			<para>
+				The <code>@IntegrationConverter</code> annotation has bean introduced,
+				as an analogue of <code>&lt;int:converter/&gt;</code> component.
+				For more information, see <xref linkend="enable-integration"/>.
+			</para>
+		</section>
 		<section id="4.0-enable-publisher">
 			<title>@EnablePublisher</title>
 			<para>