Add DebugSettings

Closes gh-73

Author: rwinch

README.adoc

@@ -164,7 +164,30 @@ static CommonsExecWebServerFactoryBean configServer() {
 }
 ----
 
+=== Debugging
 
+If you need to start the application in debug mode, you can do so using the `DebugSettings`.
+
+[source,java]
+----
+@Bean
+@OAuth2ClientProviderIssuerUri
+static CommonsExecWebServerFactoryBean authorizationServer() {
+	// @formatter:off
+	return CommonsExecWebServerFactoryBean.builder()
+		// ...
+		.debug((settings) -> settings
+			.enabled(true)
+			// Optional properties with their explicit defaults shown below
+			.suspend(true)
+			.port(5005)
+		);
+	// @formatter:on
+}
+----
+
+When starting the remote debugger, it is important to remember that the classpath of the `CommonsExecWebServerFactoryBean` is independent of the project it runs in.
+This means, the classpath of the debugger will need to match the classpat of the `CommonsExecWebServerFactoryBean` rather than the project it exists in.
 
 [[dynamicproperty]]
 == @DynamicProperty

spring-boot-testjars/src/main/java/org/springframework/experimental/boot/server/exec/CommonsExecWebServerFactoryBean.java

@@ -62,9 +62,7 @@ public class CommonsExecWebServerFactoryBean
 
 	private CommonsExecWebServer webServer;
 
-	private Integer debugPort;
-
-	private boolean suspend = true;
+	private final DebugSettings debugSettings = new DebugSettings();
 
 	CommonsExecWebServerFactoryBean() {
 		Class<?> jarDetector = ClassUtils.resolveClassName(this.mainClass, null);
@@ -121,23 +119,12 @@ public CommonsExecWebServerFactoryBean systemProperties(Consumer<Map<String, Str
 	}
 
 	/**
-	 * If set, will start up in debug mode listening on the specified port.
-	 * @param debugPort the port to listen on or null (default) to disable debug mode.
+	 * If set, will start up in debug mode using the provided settings.
+	 * @param debugSettings the settings to use.
 	 * @return the {@link CommonsExecWebServerFactoryBean} for customization.
 	 */
-	public CommonsExecWebServerFactoryBean debugPort(Integer debugPort) {
-		this.debugPort = debugPort;
-		return this;
-	}
-
-	/**
-	 * If {@link #debugPort(Integer)} is set, then this determines if the server should be
-	 * suspended or not.
-	 * @param suspend true if should suspend, else false.
-	 * @return the {@link CommonsExecWebServerFactoryBean} for customization.
-	 */
-	public CommonsExecWebServerFactoryBean suspend(boolean suspend) {
-		this.suspend = suspend;
+	public CommonsExecWebServerFactoryBean debug(Consumer<DebugSettings> debugSettings) {
+		debugSettings.accept(this.debugSettings);
 		return this;
 	}
 
@@ -148,10 +135,10 @@ public boolean isEagerInit() {
 
 	private CommonsExecWebServer build() {
 		CommandLine commandLine = new CommandLine(this.executable);
-		if (this.debugPort != null) {
-			String s = (this.suspend) ? "y" : "n";
-			commandLine.addArgument(
-					"-agentlib:jdwp=transport=dt_socket,server=y,suspend=" + s + ",address=*:" + this.debugPort);
+		if (this.debugSettings.enabled) {
+			String s = (this.debugSettings.suspend) ? "y" : "n";
+			commandLine.addArgument("-agentlib:jdwp=transport=dt_socket,server=y,suspend=" + s + ",address=*:"
+					+ this.debugSettings.port);
 		}
 		commandLine.addArguments(createSystemPropertyArgs(), false);
 		commandLine.addArgument("-classpath", false);
@@ -221,4 +208,49 @@ public void destroy() throws Exception {
 		}
 	}
 
+	/**
+	 * The settings for debugging.
+	 *
+	 * @author Rob Winch
+	 */
+	public static class DebugSettings {
+
+		private boolean enabled;
+
+		private int port = 5005;
+
+		private boolean suspend = true;
+
+		/**
+		 * Sets if debug is enabled.
+		 * @param enabled if debug is enabled or not (default is false).
+		 * @return the {@link DebugSettings} for additional customization.
+		 */
+		public DebugSettings enabled(boolean enabled) {
+			this.enabled = enabled;
+			return this;
+		}
+
+		/**
+		 * Sets the port to be used for debugging.
+		 * @param port the port to be used (default 5005)
+		 * @return the {@link DebugSettings} for additional customization.
+		 */
+		public DebugSettings port(int port) {
+			this.port = port;
+			return this;
+		}
+
+		/**
+		 * Sets if the debugger should suspend on startup.
+		 * @param suspend sets if should suspend on startup (default true)
+		 * @return the {@link DebugSettings} for additional customization.
+		 */
+		public DebugSettings suspend(boolean suspend) {
+			this.suspend = suspend;
+			return this;
+		}
+
+	}
+
 }

spring-boot-testjars/src/test/java/org/springframework/experimental/boot/server/exec/CommonsExecWebServerFactoryBeanTests.java

@@ -177,6 +177,36 @@ void setAdditionalBeanClassNamesWhenMultipleNames() {
 						(props) -> assertThat(props).containsEntry(envName, classNames[0] + "," + classNames[1]));
 	}
 
+	@Test
+	void debugWithDefaults() throws Exception {
+		CommonsExecWebServerFactoryBean factory = CommonsExecWebServerFactoryBean.builder()
+				.debug((debug) -> debug.enabled(true));
+		CommonsExecWebServer server = factory.getObject();
+		// IDEA's default debug port is 5005
+		assertThat(server.getCommandLine().getArguments())
+				.contains("-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=*:5005");
+	}
+
+	@Test
+	void debugWithCustomPort() throws Exception {
+		CommonsExecWebServerFactoryBean factory = CommonsExecWebServerFactoryBean.builder()
+				.debug((debug) -> debug.enabled(true).port(1234));
+		CommonsExecWebServer server = factory.getObject();
+		// IDEA's default debug port is 5005
+		assertThat(server.getCommandLine().getArguments())
+				.contains("-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=*:1234");
+	}
+
+	@Test
+	void debugWithSuspendFalse() throws Exception {
+		CommonsExecWebServerFactoryBean factory = CommonsExecWebServerFactoryBean.builder()
+				.debug((debug) -> debug.enabled(true).suspend(false));
+		CommonsExecWebServer server = factory.getObject();
+		// IDEA's default debug port is 5005
+		assertThat(server.getCommandLine().getArguments())
+				.contains("-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005");
+	}
+
 	private void assertClasspathContainsResourceWithContent(List<ClasspathEntry> classpath, String resourceName,
 			String expectedContent) {
 		ClasspathEntry lastEntry = classpath.get(classpath.size() - 1);