polish

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

@@ -27,14 +27,16 @@ import org.springframework.core.convert.converter.Converter;
 class StringToBooleanConverter implements Converter<String, Boolean> {
 
 	public Boolean convert(String source) {
-		if (source.equals("true")) {
+		if (source.equals("")) {
+			return null;
+		} else if (source.equals("true")) {
 			return Boolean.TRUE;
 		}
 		else if (source.equals("false")) {
 			return Boolean.FALSE;
 		}
 		else {
-			throw new IllegalArgumentException("Invalid boolean string '" + source + "'; expected 'true' or 'false'");
+			throw new IllegalArgumentException("Invalid boolean string '" + source + "'; expected \"\", 'true', or 'false'");
 		}
 	}
 

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

@@ -53,6 +53,9 @@ class StringToNumberConverterFactory implements ConverterFactory<String, Number>
 		}
 	
 		public T convert(String source) {
+			if ("".equals(source)) {
+				return null;
+			}
 			return NumberUtils.parseNumber(source, targetType);
 		}
 	}

org.springframework.core/src/test/java/org/springframework/core/convert/support/DefaultConversionServiceTests.java

@@ -42,12 +42,39 @@ public class DefaultConversionServiceTests {
 	}
 	
 	@Test
-	public void testStringToBoolean() {
+	public void testStringToCharacterEmptyString() {
+		StringToCharacterConverter c = new StringToCharacterConverter();
+		assertEquals(null, c.convert(""));
+	}
+
+	@Test(expected=IllegalArgumentException.class)
+	public void testStringToCharacterInvalidString() {
+		new StringToCharacterConverter().convert("invalid");
+	}
+
+	@Test
+	public void testStringToBooleanTrue() {
 		StringToBooleanConverter c = new StringToBooleanConverter();
 		assertEquals(Boolean.valueOf(true), c.convert("true"));
+	}
+
+	@Test
+	public void testStringToBooleanFalse() {
+		StringToBooleanConverter c = new StringToBooleanConverter();
 		assertEquals(Boolean.valueOf(false), c.convert("false"));
 	}
 
+	@Test
+	public void testStringToBooleanEmptyString() {
+		StringToBooleanConverter c = new StringToBooleanConverter();
+		assertEquals(null, c.convert(""));
+	}
+
+	@Test(expected=IllegalArgumentException.class)
+	public void testStringToBooleanInvalidString() {
+		new StringToBooleanConverter().convert("invalid");
+	}
+
 	@Test
 	public void testStringToByte() throws Exception {
 		assertEquals(Byte.valueOf("1"), c.getConverter(Byte.class).convert("1"));
@@ -88,12 +115,28 @@ public class DefaultConversionServiceTests {
 		assertEquals(new BigDecimal("1.0"), c.getConverter(BigDecimal.class).convert("1.0"));
 	}
 
+	@Test
+	public void testStringToNumber() {
+		assertEquals(new BigDecimal("1.0"), c.getConverter(Number.class).convert("1.0"));
+	}
+
+	@Test
+	public void testStringToNumberEmptyString() {
+		assertEquals(null, c.getConverter(Number.class).convert(""));
+	}
+
 	@Test
 	public void testStringToEnum() throws Exception {
 		Converter<String, Foo> c = new StringToEnumConverterFactory().getConverter(Foo.class);
 		assertEquals(Foo.BAR, c.convert("BAR"));
 	}
 	
+	@Test
+	public void testStringToEnumEmptyString() throws Exception {
+		Converter<String, Foo> c = new StringToEnumConverterFactory().getConverter(Foo.class);
+		assertEquals(null, c.convert(""));
+	}
+	
 	public static enum Foo {
 		BAR, BAZ;
 	}