Refine the behaviour of the defaults map

Fixes #734

- allow mutability
- use Environment directly for configuration

Signed-off-by: Marius Bogoevici <mbogoevici@pivotal.io>

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/BindingServiceProperties.java

@@ -33,7 +33,10 @@ import org.springframework.cloud.stream.binder.ProducerProperties;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.EnvironmentAware;
 import org.springframework.core.convert.ConversionService;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.Environment;
 import org.springframework.integration.support.utils.IntegrationUtils;
 import org.springframework.util.Assert;
 
@@ -45,8 +48,7 @@ import org.springframework.util.Assert;
  */
 @ConfigurationProperties("spring.cloud.stream")
 @JsonInclude(Include.NON_DEFAULT)
-public class BindingServiceProperties
-		implements ApplicationContextAware, InitializingBean {
+public class BindingServiceProperties implements ApplicationContextAware, EnvironmentAware, InitializingBean {
 
 	private ConversionService conversionService;
 
@@ -118,11 +120,17 @@ public class BindingServiceProperties
 	public void setApplicationContext(ApplicationContext applicationContext)
 			throws BeansException {
 		this.applicationContext = (ConfigurableApplicationContext) applicationContext;
-		// override the bindings store with the environment-initializing version if in a
-		// Spring context
-		this.bindings = new EnvironmentEntryInitializingTreeMap<>(this.applicationContext,
-				BindingProperties.class, "spring.cloud.stream.default",
-				new TreeMap<String, BindingProperties>(String.CASE_INSENSITIVE_ORDER));
+	}
+
+	@Override
+	public void setEnvironment(Environment environment) {
+		if (environment instanceof ConfigurableEnvironment) {
+			// override the bindings store with the environment-initializing version if in
+			// a Spring context
+			this.bindings = new EnvironmentEntryInitializingTreeMap<>((ConfigurableEnvironment) environment,
+					BindingProperties.class, "spring.cloud.stream.default",
+					new TreeMap<String, BindingProperties>(String.CASE_INSENSITIVE_ORDER));
+		}
 	}
 
 	public void setConversionService(ConversionService conversionService) {

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/EnvironmentEntryInitializingTreeMap.java

@@ -23,14 +23,14 @@ import java.util.Set;
 import org.springframework.beans.BeanUtils;
 import org.springframework.boot.bind.PropertySourcesPropertyValues;
 import org.springframework.boot.bind.RelaxedDataBinder;
-import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.util.Assert;
 
 /**
  * A {@link Map} implementation that initializes its entries by binding values from the
- * supplied application context's environment. Any call to 'get()' will result in either
- * returning the existing value or initializing a new entry by binding properties with the
- * specified prefix from the environment.
+ * supplied environment. Any call to 'get()' will result in either returning the existing
+ * value or initializing a new entry by binding properties with the specified prefix from
+ * the environment.
  *
  * This is strictly intended to be used for configuration property values and not to be
  * used as a general purpose map.
@@ -41,7 +41,7 @@ import org.springframework.util.Assert;
  */
 public class EnvironmentEntryInitializingTreeMap<T> extends AbstractMap<String, T> {
 
-	private final ConfigurableApplicationContext applicationContext;
+	private final ConfigurableEnvironment environment;
 
 	private final Class<T> entryClass;
 
@@ -52,18 +52,18 @@ public class EnvironmentEntryInitializingTreeMap<T> extends AbstractMap<String,
 	/**
 	 * Constructs the map.
 	 * 
-	 * @param applicationContext the application context that supplies the property values
+	 * @param environment the environment that supplies the default property values
 	 * @param entryClass the entry class
 	 * @param defaultsPrefix the prefix for initializing the properties
 	 * @param delegate the actual map that stores the values
 	 */
-	public EnvironmentEntryInitializingTreeMap(ConfigurableApplicationContext applicationContext, Class<T> entryClass,
+	public EnvironmentEntryInitializingTreeMap(ConfigurableEnvironment environment, Class<T> entryClass,
 			String defaultsPrefix, Map<String, T> delegate) {
-		Assert.notNull(applicationContext, "The context cannot be null");
+		Assert.notNull(environment, "The environment cannot be null");
 		Assert.notNull(entryClass, "The entry class cannot be null");
 		Assert.notNull(defaultsPrefix, "The prefix for the property defaults cannot be null");
 		Assert.notNull(delegate, "The delegate cannot be null");
-		this.applicationContext = applicationContext;
+		this.environment = environment;
 		this.entryClass = entryClass;
 		this.defaultsPrefix = defaultsPrefix;
 		this.delegate = delegate;
@@ -73,16 +73,18 @@ public class EnvironmentEntryInitializingTreeMap<T> extends AbstractMap<String,
 	public T get(Object key) {
 		if (!this.delegate.containsKey(key) && key instanceof String) {
 			T entry = BeanUtils.instantiate(entryClass);
-			if (applicationContext != null) {
-				RelaxedDataBinder defaultsDataBinder = new RelaxedDataBinder(entry, defaultsPrefix);
-				defaultsDataBinder.bind(
-						new PropertySourcesPropertyValues(applicationContext.getEnvironment().getPropertySources()));
-			}
+			RelaxedDataBinder defaultsDataBinder = new RelaxedDataBinder(entry, defaultsPrefix);
+			defaultsDataBinder.bind(new PropertySourcesPropertyValues(environment.getPropertySources()));
 			this.delegate.put((String) key, entry);
 		}
 		return this.delegate.get(key);
 	}
 
+	@Override
+	public T put(String key, T value) {
+		return this.delegate.put(key, value);
+	}
+
 	@Override
 	public Set<Entry<String, T>> entrySet() {
 		return delegate.entrySet();