Add PropertyMapper.from(value)

See gh-13837

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/batch/BasicBatchConfigurer.java

@@ -122,7 +122,7 @@ public class BasicBatchConfigurer implements BatchConfigurer {
 	protected JobRepository createJobRepository() throws Exception {
 		JobRepositoryFactoryBean factory = new JobRepositoryFactoryBean();
 		PropertyMapper map = PropertyMapper.get();
-		map.from(() -> this.dataSource).to(factory::setDataSource);
+		map.from(this.dataSource).to(factory::setDataSource);
 		map.from(this::determineIsolationLevel).whenNonNull()
 				.to(factory::setIsolationLevelForCreate);
 		map.from(this.properties::getTablePrefix).whenHasText()

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/kafka/ConcurrentKafkaListenerContainerFactoryConfigurer.java

@@ -85,9 +85,8 @@ public class ConcurrentKafkaListenerContainerFactoryConfigurer {
 		PropertyMapper map = PropertyMapper.get();
 		Listener properties = this.properties.getListener();
 		map.from(properties::getConcurrency).whenNonNull().to(factory::setConcurrency);
-		map.from(() -> this.messageConverter).whenNonNull()
-				.to(factory::setMessageConverter);
-		map.from(() -> this.replyTemplate).whenNonNull().to(factory::setReplyTemplate);
+		map.from(this.messageConverter).whenNonNull().to(factory::setMessageConverter);
+		map.from(this.replyTemplate).whenNonNull().to(factory::setReplyTemplate);
 		map.from(properties::getType).whenEqualTo(Listener.Type.BATCH)
 				.toCall(() -> factory.setBatchListener(true));
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizer.java

@@ -84,7 +84,7 @@ public class TomcatWebServerFactoryCustomizer implements
 						tomcatProperties.getMaxThreads()));
 		propertyMapper.from(tomcatProperties::getMinSpareThreads).when(this::isPositive)
 				.to((minSpareThreads) -> customizeMinThreads(factory, minSpareThreads));
-		propertyMapper.from(() -> determineMaxHttpHeaderSize()).when(this::isPositive)
+		propertyMapper.from(this::determineMaxHttpHeaderSize).when(this::isPositive)
 				.to((maxHttpHeaderSize) -> customizeMaxHttpHeaderSize(factory,
 						maxHttpHeaderSize));
 		propertyMapper.from(tomcatProperties::getMaxSwallowSize).whenNonNull()

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/UndertowWebServerFactoryCustomizer.java

@@ -81,7 +81,7 @@ public class UndertowWebServerFactoryCustomizer implements
 				.to(factory::setAccessLogSuffix);
 		propertyMapper.from(accesslogProperties::isRotate)
 				.to(factory::setAccessLogRotate);
-		propertyMapper.from(() -> getOrDeduceUseForwardHeaders())
+		propertyMapper.from(this::getOrDeduceUseForwardHeaders)
 				.to(factory::setUseForwardHeaders);
 		propertyMapper.from(properties::getMaxHttpHeaderSize).when(this::isPositive)
 				.to((maxHttpHeaderSize) -> customizeMaxHttpHeaderSize(factory,

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/MultipartProperties.java

@@ -138,10 +138,10 @@ public class MultipartProperties {
 	public MultipartConfigElement createMultipartConfig() {
 		MultipartConfigFactory factory = new MultipartConfigFactory();
 		PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
-		map.from(() -> this.fileSizeThreshold).to(factory::setFileSizeThreshold);
-		map.from(() -> this.location).whenHasText().to(factory::setLocation);
-		map.from(() -> this.maxRequestSize).to(factory::setMaxRequestSize);
-		map.from(() -> this.maxFileSize).to(factory::setMaxFileSize);
+		map.from(this.fileSizeThreshold).to(factory::setFileSizeThreshold);
+		map.from(this.location).whenHasText().to(factory::setLocation);
+		map.from(this.maxRequestSize).to(factory::setMaxRequestSize);
+		map.from(this.maxFileSize).to(factory::setMaxFileSize);
 		return factory.createMultipartConfig();
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/PropertyMapper.java

@@ -91,6 +91,18 @@ public final class PropertyMapper {
 		return new PropertyMapper(this, operator);
 	}
 
+	/**
+	 * Return a new {@link Source} from the specified value that can be used to perform
+	 * the mapping.
+	 * @param <T> the source type
+	 * @param value the value
+	 * @return a {@link Source} that can be used to complete the mapping
+	 * @see #from(Supplier)
+	 */
+	public <T> Source<T> from(T value) {
+		return from(() -> value);
+	}
+
 	/**
 	 * Return a new {@link Source} from the specified value supplier that can be used to
 	 * perform the mapping.

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/task/TaskExecutorBuilder.java

@@ -279,16 +279,15 @@ public class TaskExecutorBuilder {
 	 */
 	public <T extends ThreadPoolTaskExecutor> T configure(T taskExecutor) {
 		PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
-		map.from(() -> this.queueCapacity).to(taskExecutor::setQueueCapacity);
-		map.from(() -> this.corePoolSize).to(taskExecutor::setCorePoolSize);
-		map.from(() -> this.maxPoolSize).to(taskExecutor::setMaxPoolSize);
-		map.from(() -> this.keepAlive).asInt(Duration::getSeconds)
+		map.from(this.queueCapacity).to(taskExecutor::setQueueCapacity);
+		map.from(this.corePoolSize).to(taskExecutor::setCorePoolSize);
+		map.from(this.maxPoolSize).to(taskExecutor::setMaxPoolSize);
+		map.from(this.keepAlive).asInt(Duration::getSeconds)
 				.to(taskExecutor::setKeepAliveSeconds);
-		map.from(() -> this.allowCoreThreadTimeOut)
-				.to(taskExecutor::setAllowCoreThreadTimeOut);
-		map.from(() -> this.threadNamePrefix).whenHasText()
+		map.from(this.allowCoreThreadTimeOut).to(taskExecutor::setAllowCoreThreadTimeOut);
+		map.from(this.threadNamePrefix).whenHasText()
 				.to(taskExecutor::setThreadNamePrefix);
-		map.from(() -> this.taskDecorator).to(taskExecutor::setTaskDecorator);
+		map.from(this.taskDecorator).to(taskExecutor::setTaskDecorator);
 
 		if (!CollectionUtils.isEmpty(this.taskExecutorCustomizers)) {
 			for (TaskExecutorCustomizer customizer : this.taskExecutorCustomizers) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/task/TaskSchedulerBuilder.java

@@ -167,8 +167,8 @@ public class TaskSchedulerBuilder {
 	 */
 	public <T extends ThreadPoolTaskScheduler> T configure(T taskScheduler) {
 		PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
-		map.from(() -> this.poolSize).to(taskScheduler::setPoolSize);
-		map.from(() -> this.threadNamePrefix).to(taskScheduler::setThreadNamePrefix);
+		map.from(this.poolSize).to(taskScheduler::setPoolSize);
+		map.from(this.threadNamePrefix).to(taskScheduler::setThreadNamePrefix);
 
 		if (!CollectionUtils.isEmpty(this.taskSchedulerCustomizers)) {
 			for (TaskSchedulerCustomizer customizer : this.taskSchedulerCustomizers) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/webservices/client/WebServiceTemplateBuilder.java

@@ -502,13 +502,12 @@ public class WebServiceTemplateBuilder {
 		configureMessageSenders(webServiceTemplate);
 		PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
 		applyCustomizers(webServiceTemplate, this.internalCustomizers);
-		map.from(() -> this.marshaller).to(webServiceTemplate::setMarshaller);
-		map.from(() -> this.unmarshaller).to(webServiceTemplate::setUnmarshaller);
-		map.from(() -> this.destinationProvider)
-				.to(webServiceTemplate::setDestinationProvider);
-		map.from(() -> this.transformerFactoryClass)
+		map.from(this.marshaller).to(webServiceTemplate::setMarshaller);
+		map.from(this.unmarshaller).to(webServiceTemplate::setUnmarshaller);
+		map.from(this.destinationProvider).to(webServiceTemplate::setDestinationProvider);
+		map.from(this.transformerFactoryClass)
 				.to(webServiceTemplate::setTransformerFactoryClass);
-		map.from(() -> this.messageFactory).to(webServiceTemplate::setMessageFactory);
+		map.from(this.messageFactory).to(webServiceTemplate::setMessageFactory);
 		if (!CollectionUtils.isEmpty(this.interceptors)) {
 			Set<ClientInterceptor> merged = new LinkedHashSet<>(this.interceptors);
 			if (webServiceTemplate.getInterceptors() != null) {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/PropertyMapperTests.java

@@ -37,11 +37,37 @@ public class PropertyMapperTests {
 	@Rule
 	public ExpectedException thrown = ExpectedException.none();
 
+	@Test
+	public void fromNullValue() {
+		ExampleDest dest = new ExampleDest();
+		this.map.from((String) null).to(dest::setName);
+		assertThat(dest.getName()).isNull();
+	}
+
+	@Test
+	public void fromValue() {
+		ExampleDest dest = new ExampleDest();
+		this.map.from("Hello World").to(dest::setName);
+		assertThat(dest.getName()).isEqualTo("Hello World");
+	}
+
+	@Test
+	public void fromValueAsIntShouldAdaptSupplier() {
+		Integer result = this.map.from("123").asInt(Long::valueOf)
+				.toInstance(Integer::new);
+		assertThat(result).isEqualTo(123);
+	}
+
+	@Test
+	public void fromValueAlwaysApplyingWhenNonNullShouldAlwaysApplyNonNullToSource() {
+		this.map.alwaysApplyingWhenNonNull().from((String) null).toCall(Assert::fail);
+	}
+
 	@Test
 	public void fromWhenSupplierIsNullShouldThrowException() {
 		this.thrown.expect(IllegalArgumentException.class);
 		this.thrown.expectMessage("Supplier must not be null");
-		this.map.from(null);
+		this.map.from((Supplier<?>) null);
 	}
 
 	@Test