Polish "Add loadOnStartup property to EndpointServlet"

Closes gh-16053

Author: snicoll

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/EndpointServlet.java

@@ -21,6 +21,7 @@
 import java.util.Map;
 
 import javax.servlet.Servlet;
+import javax.servlet.ServletRegistration;
 
 import org.springframework.beans.BeanUtils;
 import org.springframework.util.Assert;
@@ -30,36 +31,35 @@
  * Contains details of a servlet that is exposed as an actuator endpoint.
  *
  * @author Phillip Webb
+ * @author Julio José Gómez Díaz
  */
 public final class EndpointServlet {
 
 	private final Servlet servlet;
 
-	private final int loadOnStartup;
-
 	private final Map<String, String> initParameters;
 
+	private final int loadOnStartup;
+
 	public EndpointServlet(Class<? extends Servlet> servlet) {
-		Assert.notNull(servlet, "Servlet must not be null");
-		this.servlet = BeanUtils.instantiateClass(servlet);
-		this.initParameters = Collections.emptyMap();
-		this.loadOnStartup = -1;
+		this(instantiateClass(servlet));
+	}
 
+	private static Servlet instantiateClass(Class<? extends Servlet> servlet) {
+		Assert.notNull(servlet, "Servlet must not be null");
+		return BeanUtils.instantiateClass(servlet);
 	}
 
 	public EndpointServlet(Servlet servlet) {
-		Assert.notNull(servlet, "Servlet must not be null");
-		this.servlet = servlet;
-		this.initParameters = Collections.emptyMap();
-		this.loadOnStartup = -1;
+		this(servlet, Collections.emptyMap(), -1);
 	}
 
 	private EndpointServlet(Servlet servlet, Map<String, String> initParameters,
 			int loadOnStartup) {
+		Assert.notNull(servlet, "Servlet must not be null");
 		this.servlet = servlet;
 		this.initParameters = Collections.unmodifiableMap(initParameters);
 		this.loadOnStartup = loadOnStartup;
-
 	}
 
 	public EndpointServlet withInitParameter(String name, String value) {
@@ -80,13 +80,11 @@ public EndpointServlet withInitParameters(Map<String, String> initParameters) {
 	}
 
 	/**
-	 * Sets the <code>loadOnStartup</code> priority that will be set on Servlet
-	 * registration
-	 * <p>
-	 * The default value for <tt>loadOnStartup</tt> is <code>-1</code>.
+	 * Sets the {@code loadOnStartup} priority that will be set on Servlet registration.
+	 * The default value for {@code loadOnStartup} is {@code -1}.
 	 * @param loadOnStartup the initialization priority of the Servlet
 	 * @return a new instance of {@link EndpointServlet} with the provided
-	 * <tt>loadOnStartup</tt> value set
+	 * {@code loadOnStartup} value set
 	 * @since 2.2.0
 	 * @see ServletRegistration.Dynamic#setLoadOnStartup(int)
 	 */

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/EndpointServletTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,14 +16,12 @@
 
 package org.springframework.boot.actuate.endpoint.web;
 
-import java.io.IOException;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
 import javax.servlet.GenericServlet;
 import javax.servlet.Servlet;
-import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 
@@ -129,7 +127,6 @@ public void withInitParametersWhenHasExistingShouldMergeParameters() {
 		extra.put("e", "f");
 		assertThat(endpointServlet.withInitParameters(extra).getInitParameters())
 				.containsExactly(entry("a", "b1"), entry("c", "d"), entry("e", "f"));
-
 	}
 
 	@Test
@@ -140,29 +137,15 @@ public void withLoadOnStartupNotSetShouldReturnDefaultValue() {
 
 	@Test
 	public void withLoadOnStartupSetShouldReturnValue() {
-		final int loadOnStartupTestValue = 3;
-		EndpointServlet endpointServlet = new EndpointServlet(TestServlet.class)
-				.withLoadOnStartup(loadOnStartupTestValue);
-		assertThat(endpointServlet.getLoadOnStartup()).isEqualTo(loadOnStartupTestValue);
-	}
-
-	@Test
-	public void withLoadOnStartupAndInitParamsShouldReturnValue() {
-		final int loadOnStartupTestValue = 9;
 		EndpointServlet endpointServlet = new EndpointServlet(TestServlet.class)
-				.withLoadOnStartup(loadOnStartupTestValue).withInitParameter("a", "b")
-				.withInitParameter("c", "d");
-		Map<String, String> extra = new LinkedHashMap<>();
-		extra.put("a", "b1");
-		extra.put("e", "f");
-		assertThat(endpointServlet.getLoadOnStartup()).isEqualTo(loadOnStartupTestValue);
+				.withLoadOnStartup(3);
+		assertThat(endpointServlet.getLoadOnStartup()).isEqualTo(3);
 	}
 
 	private static class TestServlet extends GenericServlet {
 
 		@Override
-		public void service(ServletRequest req, ServletResponse res)
-				throws ServletException, IOException {
+		public void service(ServletRequest req, ServletResponse res) {
 		}
 
 	}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/web/ServletEndpointRegistrarTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -123,14 +123,12 @@ public void onStartupWhenHasInitParametersShouldRegisterInitParameters()
 	@Test
 	public void onStartupWhenHasLoadOnStartupShouldRegisterLoadOnStartup()
 			throws Exception {
-		final int loadOnStartupTestValue = 7;
 		ExposableServletEndpoint endpoint = mockEndpoint(
-				new EndpointServlet(TestServlet.class)
-						.withLoadOnStartup(loadOnStartupTestValue));
+				new EndpointServlet(TestServlet.class).withLoadOnStartup(7));
 		ServletEndpointRegistrar registrar = new ServletEndpointRegistrar("/actuator",
 				Collections.singleton(endpoint));
 		registrar.onStartup(this.servletContext);
-		verify(this.dynamic).setLoadOnStartup(loadOnStartupTestValue);
+		verify(this.dynamic).setLoadOnStartup(7);
 	}
 
 	@Test