Add version properties for banner.txt usage

Extract banner.txt logic to ResourceBanner and include support for
`spring-boot.version` and `application.version` properties.

Fixes gh-1586

spring-boot/src/main/java/org/springframework/boot/Banner.java

@@ -32,8 +32,9 @@ public interface Banner {
 	/**
 	 * Print the banner to the specified print stream.
 	 * @param environment the spring environment
+	 * @param sourceClass the source class for the application
 	 * @param out the output print stream
 	 */
-	void printBanner(Environment environment, PrintStream out);
+	void printBanner(Environment environment, Class<?> sourceClass, PrintStream out);
 
 }

spring-boot/src/main/java/org/springframework/boot/ResourceBanner.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2012-2014 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot;
+
+import java.io.PrintStream;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.core.env.Environment;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.PropertyResolver;
+import org.springframework.core.env.PropertySourcesPropertyResolver;
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+import org.springframework.util.StreamUtils;
+
+/**
+ * Banner implementation that prints from a source {@link Resource}.
+ *
+ * @author Phillip Webb
+ * @since 1.2.0
+ */
+public class ResourceBanner implements Banner {
+
+	private static final Log log = LogFactory.getLog(ResourceBanner.class);
+
+	private Resource resource;
+
+	public ResourceBanner(Resource resource) {
+		Assert.notNull(resource, "Resource must not be null");
+		Assert.isTrue(resource.exists(), "Resource must exist");
+		this.resource = resource;
+	}
+
+	@Override
+	public void printBanner(Environment environment, Class<?> sourceClass, PrintStream out) {
+		try {
+			String banner = StreamUtils.copyToString(
+					this.resource.getInputStream(),
+					environment.getProperty("banner.charset", Charset.class,
+							Charset.forName("UTF-8")));
+
+			for (PropertyResolver resolver : getPropertyResolvers(environment,
+					sourceClass)) {
+				banner = resolver.resolvePlaceholders(banner);
+			}
+			out.println(banner);
+		}
+		catch (Exception ex) {
+			log.warn("Banner not printable: " + this.resource + " (" + ex.getClass()
+					+ ": '" + ex.getMessage() + "')", ex);
+		}
+	}
+
+	protected List<PropertyResolver> getPropertyResolvers(Environment environment,
+			Class<?> sourceClass) {
+		List<PropertyResolver> resolvers = new ArrayList<PropertyResolver>();
+		resolvers.add(environment);
+		resolvers.add(getVersionResolver(sourceClass));
+		return resolvers;
+	}
+
+	private PropertyResolver getVersionResolver(Class<?> sourceClass) {
+		MutablePropertySources propertySources = new MutablePropertySources();
+		propertySources.addLast(new MapPropertySource("version",
+				getVersionsMap(sourceClass)));
+		return new PropertySourcesPropertyResolver(propertySources);
+	}
+
+	private Map<String, Object> getVersionsMap(Class<?> sourceClass) {
+		String applicationVersion = (sourceClass == null ? null : sourceClass
+				.getPackage().getImplementationVersion());
+		String bootVersion = Banner.class.getPackage().getImplementationVersion();
+		Map<String, Object> versions = new HashMap<String, Object>();
+		versions.put("application.version", getVersionString(applicationVersion));
+		versions.put("spring-boot.version", getVersionString(bootVersion));
+		return versions;
+	}
+
+	private String getVersionString(String version) {
+		return (version == null ? "" : " (v" + version + ")");
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -17,7 +17,6 @@
 package org.springframework.boot;
 
 import java.lang.reflect.Constructor;
-import java.nio.charset.Charset;
 import java.security.AccessControlException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -67,7 +66,6 @@ import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StopWatch;
-import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.context.ConfigurableWebApplicationContext;
 import org.springframework.web.context.WebApplicationContext;
@@ -482,32 +480,19 @@ public class SpringApplication {
 				: new DefaultResourceLoader(getClassLoader());
 		Resource resource = resourceLoader.getResource(location);
 		if (resource.exists()) {
-			printBannerResource(environment, resource);
+			new ResourceBanner(resource).printBanner(environment,
+					this.mainApplicationClass, System.out);
 			return;
 		}
 
 		if (this.banner != null) {
-			this.banner.printBanner(environment, System.out);
+			this.banner.printBanner(environment, this.mainApplicationClass, System.out);
 			return;
 		}
 
 		printBanner();
 	}
 
-	private void printBannerResource(Environment environment, Resource resource) {
-		try {
-			String banner = StreamUtils.copyToString(
-					resource.getInputStream(),
-					environment.getProperty("banner.charset", Charset.class,
-							Charset.forName("UTF-8")));
-			System.out.println(environment.resolvePlaceholders(banner));
-		}
-		catch (Exception ex) {
-			this.log.warn("Banner not printable: " + resource + " (" + ex.getClass()
-					+ ": '" + ex.getMessage() + "')", ex);
-		}
-	}
-
 	/**
 	 * Print a simple banner message to the console. Subclasses can override this method
 	 * to provide additional or alternative banners.
@@ -517,7 +502,7 @@ public class SpringApplication {
 	 */
 	@Deprecated
 	protected void printBanner() {
-		DEFAULT_BANNER.printBanner(null, System.out);
+		DEFAULT_BANNER.printBanner(null, this.mainApplicationClass, System.out);
 	}
 
 	/**

spring-boot/src/main/java/org/springframework/boot/SpringBootBanner.java

@@ -45,7 +45,8 @@ class SpringBootBanner implements Banner {
 	private static final int STRAP_LINE_SIZE = 42;
 
 	@Override
-	public void printBanner(Environment environment, PrintStream printStream) {
+	public void printBanner(Environment environment, Class<?> sourceClass,
+			PrintStream printStream) {
 		for (String line : BANNER) {
 			printStream.println(line);
 		}

spring-boot/src/test/java/org/springframework/boot/BannerTests.java

@@ -58,7 +58,8 @@ public class BannerTests {
 	static class DummyBanner implements Banner {
 
 		@Override
-		public void printBanner(Environment environment, PrintStream out) {
+		public void printBanner(Environment environment, Class<?> sourceClass,
+				PrintStream out) {
 			out.println("My Banner");
 		}
 

spring-boot/src/test/java/org/springframework/boot/ResourceBannerTests.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2012-2014 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.util.Collections;
+import java.util.Map;
+
+import org.junit.Test;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.Resource;
+import org.springframework.mock.env.MockEnvironment;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.startsWith;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Tests for {@link ResourceBanner}.
+ *
+ * @author Phillip Webb
+ */
+public class ResourceBannerTests {
+
+	@Test
+	public void renderWithReplacement() throws Exception {
+		Resource resource = new ByteArrayResource(
+				"banner ${a} ${spring-boot.version} ${application.version}".getBytes());
+		ResourceBanner banner = new ResourceBanner(resource);
+		ConfigurableEnvironment environment = new MockEnvironment();
+		Map<String, Object> source = Collections.<String, Object> singletonMap("a", "1");
+		environment.getPropertySources().addLast(new MapPropertySource("map", source));
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		banner.printBanner(environment, getClass(), new PrintStream(out));
+		assertThat(out.toString(), startsWith("banner 1"));
+		assertThat(out.toString(), not(containsString("$")));
+	}
+
+}