refined PropertyEditor exposure for the ConversionService case

org.springframework.context/src/main/java/org/springframework/validation/AbstractPropertyBindingResult.java

@@ -117,9 +117,8 @@ public abstract class AbstractPropertyBindingResult extends AbstractBindingResul
 		if (this.conversionService != null) {
 			// Try custom formatter...
 			TypeDescriptor fieldDesc = getPropertyAccessor().getPropertyTypeDescriptor(fixedField);
-			TypeDescriptor stringDesc = TypeDescriptor.valueOf(String.class);
-			if (fieldDesc != null && this.conversionService.canConvert(fieldDesc, stringDesc)) {
-				return this.conversionService.convert(value, fieldDesc, stringDesc);
+			if (fieldDesc != null && this.conversionService.canConvert(fieldDesc, TypeDescriptor.STRING)) {
+				return this.conversionService.convert(value, fieldDesc, TypeDescriptor.STRING);
 			}
 		}
 		return value;
@@ -153,7 +152,9 @@ public abstract class AbstractPropertyBindingResult extends AbstractBindingResul
 			TypeDescriptor td = (field != null ?
 					getPropertyAccessor().getPropertyTypeDescriptor(fixedField(field)) :
 					TypeDescriptor.valueOf(valueType));
-			editor = new ConvertingPropertyEditorAdapter(this.conversionService, td);
+			if (this.conversionService.canConvert(TypeDescriptor.STRING, td)) {
+				editor = new ConvertingPropertyEditorAdapter(this.conversionService, td);
+			}
 		}
 		return editor;
 	}

org.springframework.core/src/main/java/org/springframework/core/convert/support/ConvertingPropertyEditorAdapter.java

@@ -31,12 +31,12 @@ import org.springframework.util.Assert;
  */
 public class ConvertingPropertyEditorAdapter extends PropertyEditorSupport {
 
-	private static final TypeDescriptor stringDescriptor = TypeDescriptor.valueOf(String.class);
-
 	private final ConversionService conversionService;
 
 	private final TypeDescriptor targetDescriptor;
 
+	private final boolean canConvertToString;
+
 
 	/**
 	 * Create a new ConvertingPropertyEditorAdapter for a given
@@ -50,17 +50,23 @@ public class ConvertingPropertyEditorAdapter extends PropertyEditorSupport {
 		Assert.notNull(targetDescriptor, "TypeDescriptor must not be null");
 		this.conversionService = conversionService;
 		this.targetDescriptor = targetDescriptor;
+		this.canConvertToString = conversionService.canConvert(this.targetDescriptor, TypeDescriptor.STRING);
 	}
 
 
 	@Override
 	public void setAsText(String text) throws IllegalArgumentException {
-		setValue(this.conversionService.convert(text, stringDescriptor, this.targetDescriptor));
+		setValue(this.conversionService.convert(text, TypeDescriptor.STRING, this.targetDescriptor));
 	}
 
 	@Override
 	public String getAsText() {
-		return (String) this.conversionService.convert(getValue(), this.targetDescriptor, stringDescriptor);
+		if (this.canConvertToString) {
+			return (String) this.conversionService.convert(getValue(), this.targetDescriptor, TypeDescriptor.STRING);
+		}
+		else {
+			return null;
+		}
 	}
 
 }

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/tags/form/ValueFormatter.java

 /*
- * Copyright 2002-2007 the original author or authors.
+ * Copyright 2002-2009 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.
@@ -59,16 +59,16 @@ abstract class ValueFormatter {
 		if (propertyEditor != null && !(value instanceof String)) {
 			try {
 				propertyEditor.setValue(value);
-				return getDisplayString(propertyEditor.getAsText(), htmlEscape);
+				String text = propertyEditor.getAsText();
+				if (text != null) {
+					return getDisplayString(text, htmlEscape);
+				}
 			}
 			catch (Throwable ex) {
 				// The PropertyEditor might not support this value... pass through.
-				return getDisplayString(value, htmlEscape);
 			}
 		}
-		else {
-			return getDisplayString(value, htmlEscape);
-		}
+		return getDisplayString(value, htmlEscape);
 	}
 
 }