Beefed up test suite

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

@@ -37,7 +37,7 @@ final class ArrayToArrayGenericConverter implements GenericConverter {
 		Object target = Array.newInstance(targetElementType.getType(), Array.getLength(source));
 		GenericConverter converter = this.conversionService.getConverter(sourceElementType, targetElementType);		
 		if (converter == null) {
-			throw new ConverterNotFoundException(sourceType, targetType);
+			throw new ConverterNotFoundException(sourceElementType, targetElementType);
 		}
 		for (int i = 0; i < Array.getLength(target); i++) {
 			Array.set(target, i, converter.convert(Array.get(source, i), sourceElementType, targetElementType));

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

@@ -42,7 +42,7 @@ final class ArrayToCollectionGenericConverter implements GenericConverter {
 		} else {
 			GenericConverter converter = this.conversionService.getConverter(sourceElementType, targetElementType);
 			if (converter == null) {
-				throw new ConverterNotFoundException(sourceType, targetType);
+				throw new ConverterNotFoundException(sourceElementType, targetElementType);
 			}			
 			for (int i = 0; i < length; i++) {
 				collection.add(converter.convert(Array.get(source, i), sourceElementType, targetElementType));

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

@@ -39,7 +39,7 @@ final class ArrayToObjectGenericConverter implements GenericConverter {
 			} else {
 				GenericConverter converter = this.conversionService.getConverter(sourceElementType, targetType);
 				if (converter == null) {
-					throw new ConverterNotFoundException(sourceType, targetType);
+					throw new ConverterNotFoundException(sourceElementType, targetType);
 				}
 				return converter.convert(Array.get(source, 0), sourceElementType, targetType);
 			}

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

@@ -46,7 +46,7 @@ final class CollectionToArrayGenericConverter implements GenericConverter {
 		} else {
 			GenericConverter converter = this.conversionService.getConverter(sourceElementType, targetElementType);
 			if (converter == null) {
-				throw new ConverterNotFoundException(sourceType, targetType);
+				throw new ConverterNotFoundException(sourceElementType, targetElementType);
 			}			
 			for (Iterator it = sourceCollection.iterator(); it.hasNext(); i++) {
 				Array.set(array, i, converter.convert(it.next(), sourceElementType, targetElementType));

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

@@ -28,7 +28,7 @@ final class CollectionToCollectionGenericConverter implements GenericConverter {
 	public CollectionToCollectionGenericConverter(GenericConversionService conversionService) {
 		this.conversionService = conversionService;
 	}
-	
+
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		Collection sourceCollection = (Collection) source;
 		TypeDescriptor sourceElementType = sourceType.getElementTypeDescriptor();
@@ -40,7 +40,8 @@ final class CollectionToCollectionGenericConverter implements GenericConverter {
 			if (sourceType.isAssignableTo(targetType)) {
 				return sourceCollection;
 			} else {
-				Collection targetCollection = CollectionFactory.createCollection(targetType.getType(), sourceCollection.size());
+				Collection targetCollection = CollectionFactory.createCollection(targetType.getType(), sourceCollection
+						.size());
 				targetCollection.addAll(sourceCollection);
 				return targetCollection;
 			}
@@ -48,14 +49,14 @@ final class CollectionToCollectionGenericConverter implements GenericConverter {
 		Collection targetCollection = CollectionFactory.createCollection(targetType.getType(), sourceCollection.size());
 		GenericConverter converter = this.conversionService.getConverter(sourceElementType, targetElementType);
 		if (converter == null) {
-			throw new ConverterNotFoundException(sourceType, targetType);
+			throw new ConverterNotFoundException(sourceElementType, targetElementType);
-		}		
+		}
 		for (Object element : sourceCollection) {
 			targetCollection.add(converter.convert(element, sourceElementType, targetElementType));
 		}
 		return targetCollection;
 	}
-	
+
 	private TypeDescriptor getElementType(Collection collection) {
 		for (Object element : collection) {
 			if (element != null) {

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

@@ -33,15 +33,19 @@ final class CollectionToObjectGenericConverter implements GenericConverter {
 		if (sourceCollection.size() == 0) {
 			return null;
 		} else {
+			Object firstElement = sourceCollection.iterator().next();			
 			TypeDescriptor sourceElementType = sourceType.getElementTypeDescriptor();
+			if (sourceElementType == TypeDescriptor.NULL && firstElement != null) {
+				sourceElementType = TypeDescriptor.valueOf(firstElement.getClass());
+			}			
 			if (sourceElementType == TypeDescriptor.NULL || sourceElementType.isAssignableTo(targetType)) {
-				return sourceCollection.iterator().next();
+				return firstElement;
 			} else {
 				GenericConverter converter = this.conversionService.getConverter(sourceElementType, targetType);
 				if (converter == null) {
-					throw new ConverterNotFoundException(sourceType, targetType);
+					throw new ConverterNotFoundException(sourceElementType, targetType);
 				}				
-				return converter.convert(sourceCollection.iterator().next(), sourceElementType, targetType);
+				return converter.convert(firstElement, sourceElementType, targetType);
 			}
 		}
 	}

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

@@ -36,7 +36,7 @@ final class ObjectToArrayGenericConverter implements GenericConverter {
 		} else {
 			GenericConverter converter = this.conversionService.getConverter(sourceType, targetElementType);
 			if (converter == null) {
-				throw new ConverterNotFoundException(sourceType, targetType);
+				throw new ConverterNotFoundException(sourceType, targetElementType);
 			}		
 			Array.set(target, 0, converter.convert(source, sourceType, targetElementType));
 		}

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

@@ -37,7 +37,7 @@ final class ObjectToCollectionGenericConverter implements GenericConverter {
 		} else {
 			GenericConverter converter = this.conversionService.getConverter(sourceType, targetElementType);
 			if (converter == null) {
-				throw new ConverterNotFoundException(sourceType, targetType);
+				throw new ConverterNotFoundException(sourceType, targetElementType);
 			}
 			target.add(converter.convert(source, sourceType, targetElementType));
 		}

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

@@ -24,6 +24,7 @@ import static org.junit.Assert.assertTrue;
 
 import java.util.AbstractList;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
@@ -145,7 +146,7 @@ public class GenericConversionServiceTests {
 		assertEquals(2, result[1]);
 		assertEquals(3, result[2]);
 	}
-	
+
 	@Test
 	public void convertArrayToArrayAssignable() {
 		int[] result = converter.convert(new int[] { 1, 2, 3 }, int[].class);
@@ -182,7 +183,7 @@ public class GenericConversionServiceTests {
 		assertEquals("3", result.get(2));
 	}
 
-	@Test(expected=ConversionFailedException.class)
+	@Test(expected = ConversionFailedException.class)
 	public void convertArrayToAbstractList() {
 		converter.convert(new String[] { "1", "2", "3" }, AbstractList.class);
 	}
@@ -241,6 +242,37 @@ public class GenericConversionServiceTests {
 		assertEquals(map.get(2), FooEnum.BAZ);
 	}
 
+	@Test
+	public void convertObjectToCollection() {
+		List<String> result = (List<String>) converter.convert("test", List.class);
+		assertEquals(1, result.size());
+		assertEquals("test", result.get(0));
+	}
+
+	@Test
+	public void convertObjectToCollectionWithElementConversion() throws Exception {
+		converter.addConverterFactory(new StringToNumberConverterFactory());		
+		List<Integer> result = (List<Integer>) converter.convert("3", TypeDescriptor.valueOf(String.class),
+				new TypeDescriptor(getClass().getField("genericList")));
+		assertEquals(1, result.size());
+		assertEquals(new Integer(3), result.get(0));
+	}
+
+	@Test
+	public void convertCollectionToObject() {
+		List<String> list = Collections.singletonList("test");
+		String result = converter.convert(list, String.class);
+		assertEquals("test", result);
+	}
+
+	@Test
+	public void convertCollectionToObjectWithElementConversion() {
+		converter.addConverterFactory(new StringToNumberConverterFactory());		
+		List<String> list = Collections.singletonList("3");		
+		Integer result = converter.convert(list, Integer.class);
+		assertEquals(new Integer(3), result);
+	}
+
 	@Test
 	public void convertObjectToArray() {
 		String[] result = converter.convert("test", String[].class);
@@ -256,6 +288,21 @@ public class GenericConversionServiceTests {
 		assertEquals(new Integer(1), result[0]);
 	}
 
+	@Test
+	public void convertArrayToObject() {
+		String[] array = new String[] { "test" };
+		String result = converter.convert(array, String.class);
+		assertEquals("test", result);
+	}
+	
+	@Test
+	public void convertArrayToObjectWithElementConversion() {
+		converter.addConverterFactory(new StringToNumberConverterFactory());
+		String[] array = new String[] { "3" };
+		Integer result = converter.convert(array, Integer.class);
+		assertEquals(new Integer(3), result);
+	}
+	
 	@Test
 	@Ignore
 	public void convertStringToArrayWithElementConversion() {
@@ -275,7 +322,7 @@ public class GenericConversionServiceTests {
 			assertTrue(e.getCause() instanceof ConverterNotFoundException);
 		}
 	}
-	
+
 	@Test
 	public void parent() {
 		GenericConversionService parent = new GenericConversionService();
@@ -284,7 +331,7 @@ public class GenericConversionServiceTests {
 		try {
 			converter.convert("3", Integer.class);
 		} catch (ConverterNotFoundException e) {
-			
+
 		}
 	}