Allow additional paths that trigger a reload/restart to be configured

Previously, only folders on the classpath would be watched and used
to trigger a restart/reload of the application. This commit adds a
new property spring.devtools.restart.additional-paths that can be
used to configure additional paths that should be watched for
changes. When a change occurs in one of those paths a restart or
reload will be triggered, depending on the full restart exclude
patterns configured via the existing spring.devtools.restart.exclude
property.

Closes gh-3469

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/autoconfigure/DevToolsProperties.java

@@ -16,6 +16,10 @@
 
 package org.springframework.boot.devtools.autoconfigure;
 
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 
@@ -87,6 +91,11 @@ public class DevToolsProperties {
 		 */
 		private String triggerFile;
 
+		/**
+		 * Additional paths to watch for changes.
+		 */
+		private List<File> additionalPaths = new ArrayList<File>();
+
 		public boolean isEnabled() {
 			return this.enabled;
 		}
@@ -127,6 +136,14 @@ public class DevToolsProperties {
 			this.triggerFile = triggerFile;
 		}
 
+		public List<File> getAdditionalPaths() {
+			return this.additionalPaths;
+		}
+
+		public void setAdditionalPaths(List<File> additionalPaths) {
+			this.additionalPaths = additionalPaths;
+		}
+
 	}
 
 	/**

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/autoconfigure/LocalDevToolsAutoConfiguration.java

@@ -16,7 +16,9 @@
 
 package org.springframework.boot.devtools.autoconfigure;
 
+import java.io.File;
 import java.net.URL;
+import java.util.List;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
@@ -158,6 +160,10 @@ public class LocalDevToolsAutoConfiguration {
 			if (StringUtils.hasLength(triggerFile)) {
 				watcher.setTriggerFilter(new TriggerFileFilter(triggerFile));
 			}
+			List<File> additionalPaths = restartProperties.getAdditionalPaths();
+			for (File path : additionalPaths) {
+				watcher.addSourceFolder(path.getAbsoluteFile());
+			}
 			return watcher;
 		}
 

spring-boot-devtools/src/test/java/org/springframework/boot/devtools/autoconfigure/LocalDevToolsAutoConfigurationTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.devtools.autoconfigure;
 
+import java.io.File;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
@@ -45,7 +46,9 @@ import org.springframework.util.SocketUtils;
 import org.thymeleaf.templateresolver.TemplateResolver;
 
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasKey;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.junit.Assert.assertThat;
 import static org.mockito.Matchers.any;
@@ -181,6 +184,24 @@ public class LocalDevToolsAutoConfigurationTests {
 		assertThat(filter, instanceOf(TriggerFileFilter.class));
 	}
 
+	@Test
+	public void watchingAdditionalPaths() throws Exception {
+		Map<String, Object> properties = new HashMap<String, Object>();
+		properties.put("spring.devtools.restart.additional-paths",
+				"src/main/java,src/test/java");
+		this.context = initializeAndRun(Config.class, properties);
+		ClassPathFileSystemWatcher classPathWatcher = this.context
+				.getBean(ClassPathFileSystemWatcher.class);
+		Object watcher = ReflectionTestUtils.getField(classPathWatcher,
+				"fileSystemWatcher");
+		@SuppressWarnings("unchecked")
+		Map<File, Object> folders = (Map<File, Object>) ReflectionTestUtils.getField(
+				watcher, "folders");
+		assertThat(folders.size(), is(equalTo(2)));
+		assertThat(folders, hasKey(new File("src/main/java").getAbsoluteFile()));
+		assertThat(folders, hasKey(new File("src/test/java").getAbsoluteFile()));
+	}
+
 	private ConfigurableApplicationContext initializeAndRun(Class<?> config) {
 		return initializeAndRun(config, Collections.<String, Object> emptyMap());
 	}

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -617,6 +617,7 @@ content into your application; rather pick only the properties that you need.
 	# ----------------------------------------
 
     # DEVTOOLS ({sc-spring-boot-devtools}/autoconfigure/DevToolsProperties.{sc-ext}[DevToolsProperties])
+    spring.devtools.restart.additional-paths= # additional paths to watch for changes
     spring.devtools.restart.enabled=true # enable automatic restart
     spring.devtools.restart.exclude= # patterns that should be excluding for triggering a full restart
     spring.devtools.restart.poll-interval= # amount of time (in milliseconds) to wait between polling for classpath changes

spring-boot-docs/src/main/asciidoc/using-spring-boot.adoc

@@ -894,12 +894,14 @@ commercially supported.
 
 
 
+[[using-boot-devtools-restart-exclude]]
 ==== Excluding resources
 Certain resources don't necessarily need to trigger a restart when they are changed. For
 example, Thymeleaf templates can just be edited in-place. By default changing resources
 in `/META-INF/maven`, `/META-INF/resources` ,`/resources` ,`/static` ,`/public` or
-`/templates` will not trigger a restart. If you want to customize these exclusions you
-can use the `spring.devtools.restart.exclude` property. For example, to exclude only
+`/templates` will not trigger a restart but will trigger a
+<<using-boot-devtools-livereload, live reload>>. If you want to customize these exclusions
+you can use the `spring.devtools.restart.exclude` property. For example, to exclude only
 `/static` and `/public` you would set the following:
 
 [indent=0]
@@ -909,6 +911,18 @@ can use the `spring.devtools.restart.exclude` property. For example, to exclude
 
 
 
+[[using-boot-devtools-restart-additional-paths]]
+==== Watching additional paths
+You may want your application to be restarted or reloaded when you make changes to files
+that are not on the classpath. To do so, use the
+`spring.devtools.restart.additional-paths` property to configure additional paths to watch
+for changes. You can use the `spring.devtools.restart.exclude` property
+<<using-boot-devtools-restart-exclude, described above>> to control whether changes
+beneath the additional paths will trigger a full restart or just a
+<<using-boot-devtools-livereload, live reload>>.
+
+
+
 [[using-boot-devtools-restart-disable]]
 ==== Disabling restart
 If you don't want to use the restart feature you can disable it using the