juneau-doc/docs/Topics/12.juneau-microservice-jetty/03.ResourceClasses.html

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Resource Classes

<p>
	This section describes how to define a top-level REST resource page and deploy it in our microservice.
	The example is a router page that serves as a jumping off page to child resources.
</p>
<p class='bpcode w800'>
	<ja>@Rest</ja>(
		path=<js>"/*"</js>,
		title=<js>"My Microservice"</js>,
		description=<js>"Top-level resources page"</js>,
		htmldoc=<ja>@HtmlDoc</ja>(
			navlinks={
				<js>"options: servlet:/?method=OPTIONS"</js>
			}
		),
		children={
			HelloWorldResource.<jk>class</jk>,
			ConfigResource.<jk>class</jk>,
			LogsResource.<jk>class</jk>
		}
	)
	<jk>public class</jk> RootResources <jk>extends</jk> BasicRestServletJenaGroup {
		<jc>// No code! </jc>
	}
</p>
<p>
	When deployed, it looks like this in a browser:
</p>
<p class='bpcode w800'>
	http://localhost:10000
</p>			
<img class='bordered w800' src='doc-files/juneau-microservice-jetty.Running.1.png'>
<ul class='spaced-list'>
	<li>
		The </l>title</l> and <l>description</l> annotations define the titles on the page.
		<br>These can be globalized using <l>$L{...}</l> variables, or by defining specially-named properties in the 
		properties file for the resource.
	<li>
		In this case, the <l>path</l> annotation defines the context root of your application since it was 
		not specified in the manifest or config file.
		<br>Therefore, this resource is mapped to <l>http://localhost:10000</l>.
	<li>
		The <l>children</l> annotation make up the list of child resources.
		<br>These child resources can be anything that extends from <l>Servlet</l>, although usually
		they will be subclasses of {@link oajr.BasicRestServlet} or other resource groups.
</ul>
<p>
	If you click the <l>helloWorld</l> link in your application, you'll get a simple hello world message:
</p>
<p class='bpcode w800'>
	http://localhost:10000/helloWorld
</p>			
<img class='bordered w800' src='doc-files/juneau-microservice-jetty.ResourceClasses.1.png'>
<p>
	...which is generated by this class...
</p>
<p class='bpcode w800'>
	<ja>@Rest</ja>(
		path=<js>"/helloWorld"</js>,
		title=<js>"Hello World example"</js>,
		description=<js>"Simplest possible REST resource"</js>
	)
	<jk>public class</jk> HelloWorldResource <jk>extends</jk> BasicRestServlet {
	
		<ja>@RestMethod</ja>(name=<jsf>GET</jsf>, path=<js>"/*"</js>)
		<jk>public</jk> String sayHello() {
			<jk>return</jk> <js>"Hello world!"</js>;
		}
	}		
</p>
<p>
	The most-common case for deploying the top-level resource is to use the {@link oaj.microservice.jetty.JettyMicroserviceBuilder#servlet(Class)} method:
</p>	
<p class='bpcode w800'>
	<jk>public class</jk> App {
		<jk>public static void</jk> main(String[] args) {
			JettyMicroservice
				.<jsm>create</jsm>() 
				.args(args)
				.servlet(RootResources.<jk>class</jk>) <jc>// Our root resource.</jc>
				.build() 
				.start()
			;
		}
	}
</p>
<p>
	However, there are multiple ways of deploying top-level resources:
</p>
<ul class='spaced-list'>
	<li>
		{@link oaj.microservice.jetty.JettyMicroserviceBuilder#servlet(Class)} - Using the builder.  Several methods provided.
	<li>
		{@link oaj.microservice.jetty.JettyMicroservice#addServlet(Servlet,String)} - After the Jetty container has been started.
	<li>
		As a configuration variable <js>"Jetty/servlets"</js>.
		<p class='bcode w800'>
	<cc>#=======================================================================================================================
	# Jetty settings
	#=======================================================================================================================</cc>
	<cs>[Jetty]</cs>

	<cc># Subclasses of RestServlet</cc>	
	<ck>servlets</ck> = <cv>org.apache.juneau.examples.rest.RootResources</cv>	
		</p>
	<li>
		As a configuration variable <js>"Jetty/servletMap"</js>.
		<p class='bcode w800'>
	<cc>#=======================================================================================================================
	# Jetty settings
	#=======================================================================================================================</cc>
	<cs>[Jetty]</cs>

	<cc># Any servlets and their path specs</cc>	
	<ck>servletMap</ck> = 
		<cv>{
			'/*': 'org.apache.juneau.examples.rest.RootResources'
		}</cv>
	</cv>	
	<li>
		Directly in the <c>jetty.xml</c> file.
		<p class='bcode w800'>
	<xt>&lt;Configure</xt> <xa>id</xa>=<xs>"ExampleServer"</xs> <xa>class</xa>=<xs>"org.eclipse.jetty.server.Server"</xs><xt>&gt;</xt>
		...
		<xt>&lt;New</xt> <xa>id</xa>=<xs>"context"</xs> <xa>class</xa>=<xs>"org.eclipse.jetty.servlet.ServletContextHandler"</xs><xt>&gt;</xt>
			<xt>&lt;Set</xt> <xa>name</xa>=<xs>"contextPath"</xs><xt>&gt;/&lt;/Set&gt;</xt>
			<xt>&lt;Call</xt> <xa>name</xa>=<xs>"addServlet"</xs><xt>&gt;</xt>
				<xt>&lt;Arg&gt;</xt>org.apache.juneau.rest.test.Root<xt>&lt;/Arg&gt;</xt>
				<xt>&lt;Arg&gt;</xt>/*<xt>&lt;/Arg&gt;</xt>
			<xt>&lt;/Call&gt;</xt>
			<xt>&lt;Set</xt> <xa>name</xa>=<xs>"sessionHandler"</xs><xt>&gt;</xt>
				<xt>&lt;New</xt> <xa>class</xa>=<xs>"org.eclipse.jetty.server.session.SessionHandler"</xs> <xt>/&gt;</xt>
			<xt>&lt;/Set&gt;</xt>
		<xt>&lt;/New&gt;</xt>
		...
		</p>
</ul>