Add Binder backed CloudPlatform.isEnforced method

Update `CloudPlatform` with a new `isEnforced` method that's backed
by a `Binder` rather than the `Environment`. We'll require this when
we overhaul our external config data processing logic.

Closes gh-22498

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/cloud/CloudPlatform.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.cloud;
 
+import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.EnumerablePropertySource;
 import org.springframework.core.env.Environment;
@@ -131,6 +132,8 @@ public enum CloudPlatform {
 
 	};
 
+	private static final String PROPERTY_NAME = "spring.main.cloud-platform";
+
 	/**
 	 * Determines if the platform is active (i.e. the application is running in it).
 	 * @param environment the environment
@@ -148,7 +151,21 @@ public enum CloudPlatform {
 	 * @since 2.3.0
 	 */
 	public boolean isEnforced(Environment environment) {
-		String platform = environment.getProperty("spring.main.cloud-platform");
+		return isEnforced(environment.getProperty(PROPERTY_NAME));
+	}
+
+	/**
+	 * Determines if the platform is enforced by looking at the
+	 * {@code "spring.main.cloud-platform"} configuration property.
+	 * @param binder the binder
+	 * @return if the platform is enforced
+	 * @since 2.4.0
+	 */
+	public boolean isEnforced(Binder binder) {
+		return isEnforced(binder.bind(PROPERTY_NAME, String.class).orElse(null));
+	}
+
+	private boolean isEnforced(String platform) {
 		return name().equalsIgnoreCase(platform);
 	}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/cloud/CloudPlatformTests.java

@@ -22,6 +22,8 @@ import java.util.Map;
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.boot.context.properties.bind.Binder;
+import org.springframework.boot.context.properties.source.MockConfigurationPropertySource;
 import org.springframework.core.env.Environment;
 import org.springframework.core.env.PropertySource;
 import org.springframework.core.env.StandardEnvironment;
@@ -137,6 +139,44 @@ class CloudPlatformTests {
 		assertThat(platform).isEqualTo(CloudPlatform.KUBERNETES);
 	}
 
+	@Test
+	void isEnforcedWhenEnvironmentPropertyMatchesReturnsTrue() {
+		MockEnvironment environment = new MockEnvironment();
+		environment.setProperty("spring.main.cloud-platform", "kubernetes");
+		assertThat(CloudPlatform.KUBERNETES.isEnforced(environment)).isTrue();
+	}
+
+	@Test
+	void isEnforcedWhenEnvironmentPropertyDoesNotMatchReturnsFalse() {
+		MockEnvironment environment = new MockEnvironment();
+		environment.setProperty("spring.main.cloud-platform", "heroku");
+		assertThat(CloudPlatform.KUBERNETES.isEnforced(environment)).isFalse();
+	}
+
+	@Test
+	void isEnforcedWhenEnvironmentPropertyIsMissingatchReturnsFalse() {
+		MockEnvironment environment = new MockEnvironment();
+		assertThat(CloudPlatform.KUBERNETES.isEnforced(environment)).isFalse();
+	}
+
+	@Test
+	void isEnforcedWhenBinderPropertyMatchesReturnsTrue() {
+		Binder binder = new Binder(new MockConfigurationPropertySource("spring.main.cloud-platform", "kubernetes"));
+		assertThat(CloudPlatform.KUBERNETES.isEnforced(binder)).isTrue();
+	}
+
+	@Test
+	void isEnforcedWhenBinderPropertyDoesNotMatchReturnsFalse() {
+		Binder binder = new Binder(new MockConfigurationPropertySource("spring.main.cloud-platform", "heroku"));
+		assertThat(CloudPlatform.KUBERNETES.isEnforced(binder)).isFalse();
+	}
+
+	@Test
+	void isEnforcedWhenBinderPropertyIsMissingatchReturnsFalse() {
+		Binder binder = new Binder(new MockConfigurationPropertySource());
+		assertThat(CloudPlatform.KUBERNETES.isEnforced(binder)).isFalse();
+	}
+
 	private Environment getEnvironmentWithEnvVariables(Map<String, Object> environmentVariables) {
 		MockEnvironment environment = new MockEnvironment();
 		PropertySource<?> propertySource = new SystemEnvironmentPropertySource(