Polishing.

Improve null-safety. Refine exception signature to avoid exception catching.

See #2590
Original pull request: #2591.

Author: mp911de

src/main/java/org/springframework/data/convert/PropertyValueConversions.java

@@ -61,13 +61,11 @@ static <P extends PersistentProperty<P>> PropertyValueConversions simple(
 
 		SimplePropertyValueConversions conversions = new SimplePropertyValueConversions();
 		PropertyValueConverterRegistrar registrar = new PropertyValueConverterRegistrar();
+
 		config.accept(registrar);
 		conversions.setValueConverterRegistry(registrar.buildRegistry());
-		try {
-			conversions.afterPropertiesSet();
-		} catch (Exception e) {
-			throw new IllegalStateException("Could not initialize value conversions.");
-		}
+		conversions.afterPropertiesSet();
+
 		return conversions;
 	}
 }

src/main/java/org/springframework/data/convert/SimplePropertyValueConversions.java

@@ -32,6 +32,7 @@
  * {@link PropertyValueConverter converter} retrieval.
  *
  * @author Christoph Strobl
+ * @author Mark Paluch
  * @since 2.7
  */
 public class SimplePropertyValueConversions implements PropertyValueConversions, InitializingBean {
@@ -55,6 +56,18 @@ public PropertyValueConverterFactory getConverterFactory() {
 		return converterFactory;
 	}
 
+	private PropertyValueConverterFactory obtainConverterFactory() {
+
+		PropertyValueConverterFactory factory = getConverterFactory();
+
+		if (factory == null) {
+			throw new IllegalStateException(
+					"PropertyValueConverterFactory is not set. Make sure to either set the converter factory or call afterPropertiesSet() to initialize the object.");
+		}
+
+		return factory;
+	}
+
 	/**
 	 * Set the {@link ValueConverterRegistry converter registry} for path configured converters. This is short for adding
 	 * a
@@ -78,7 +91,7 @@ public ValueConverterRegistry<?> getValueConverterRegistry() {
 	}
 
 	/**
-	 * Dis-/Enable caching. Enabled by default.
+	 * Configure whether to use converter cache. Enabled by default.
 	 *
 	 * @param converterCacheEnabled set to {@literal true} to enable caching of {@link PropertyValueConverter converter}
 	 *          instances.
@@ -89,14 +102,14 @@ public void setConverterCacheEnabled(boolean converterCacheEnabled) {
 
 	@Override
 	public boolean hasValueConverter(PersistentProperty<?> property) {
-		return this.converterFactory.getConverter(property) != null;
+		return obtainConverterFactory().getConverter(property) != null;
 	}
 
 	@Nullable
 	@Override
 	public <DV, SV, C extends PersistentProperty<C>, D extends ValueConversionContext<C>> PropertyValueConverter<DV, SV, D> getValueConverter(
 			C property) {
-		return this.converterFactory.getConverter(property);
+		return obtainConverterFactory().getConverter(property);
 	}
 
 	/**
@@ -125,7 +138,7 @@ public void init() {
 	}
 
 	@Override
-	public void afterPropertiesSet() throws Exception {
+	public void afterPropertiesSet() {
 		init();
 	}
 }