SPR-6179, additional mapper test cases

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@2047 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.context/src/main/java/org/springframework/mapping/Mapper.java

@@ -27,8 +27,9 @@ public interface Mapper<S, T> {
 	 * Map the source to the target.
 	 * @param source the source to map from
 	 * @param target the target to map to
+	 * @return the mapped target object
 	 * @throws MappingException if the mapping process failed
 	 */
-	void map(S source, T target);
+	Object map(S source, T target);
 	
 }

org.springframework.context/src/main/java/org/springframework/mapping/MappingException.java

@@ -60,11 +60,12 @@ public class MappingException extends RuntimeException {
 	public void printStackTrace(PrintStream ps) {
 		super.printStackTrace(ps);
 		synchronized (ps) {
-			ps.println("Failure cause traces:");
+			ps.println();
+			ps.println("Mapping Failure Traces:");
 			int i = 1;
 			for (Iterator<MappingFailure> it = this.mappingFailures.iterator(); it.hasNext(); i++) {
 				MappingFailure failure = it.next();
-				ps.println("- MappingFailure #" + i + " Cause: ");
+				ps.println("- MappingFailure #" + i + ":");
 				Throwable t = failure.getCause();
 				if (t != null) {
 					t.printStackTrace(ps);
@@ -79,11 +80,12 @@ public class MappingException extends RuntimeException {
 	public void printStackTrace(PrintWriter pw) {
 		super.printStackTrace(pw);
 		synchronized (pw) {
-			pw.println("Failure cause traces:");
+			pw.println();
+			pw.println("Mapping Failure Traces:");
 			int i = 1;
 			for (Iterator<MappingFailure> it = this.mappingFailures.iterator(); it.hasNext(); i++) {
 				MappingFailure failure = it.next();
-				pw.println("- MappingFailure #" + i + " Cause: ");
+				pw.println("- MappingFailure #" + i + ":");
 				Throwable t = failure.getCause();
 				if (t != null) {
 					t.printStackTrace(pw);

org.springframework.context/src/main/java/org/springframework/mapping/support/SpelMapper.java

@@ -25,6 +25,7 @@ import java.util.Set;
 import org.springframework.core.convert.converter.ConverterRegistry;
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.expression.EvaluationContext;
+import org.springframework.expression.EvaluationException;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ParseException;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
@@ -60,27 +61,27 @@ public class SpelMapper implements Mapper<Object, Object> {
 		this.autoMappingEnabled = autoMappingEnabled;
 	}
 
-	public MappingConfiguration addMapping(String expression) {
-		return addMapping(expression, expression);
+	public MappingConfiguration addMapping(String fieldExpression) {
+		return addMapping(fieldExpression, fieldExpression);
 	}
 
 	public ConverterRegistry getConverterRegistry() {
 		return conversionService;
 	}
 
-	public MappingConfiguration addMapping(String sourceExpression, String targetExpression) {
+	public MappingConfiguration addMapping(String sourceFieldExpression, String targetFieldExpression) {
 		Expression sourceExp;
 		try {
-			sourceExp = sourceExpressionParser.parseExpression(sourceExpression);
+			sourceExp = sourceExpressionParser.parseExpression(sourceFieldExpression);
 		} catch (ParseException e) {
-			throw new IllegalArgumentException("The mapping source '" + sourceExpression
+			throw new IllegalArgumentException("The mapping source '" + sourceFieldExpression
 					+ "' is not a parseable value expression", e);
 		}
 		Expression targetExp;
 		try {
-			targetExp = targetExpressionParser.parseExpression(targetExpression);
+			targetExp = targetExpressionParser.parseExpression(targetFieldExpression);
 		} catch (ParseException e) {
-			throw new IllegalArgumentException("The mapping target '" + targetExpression
+			throw new IllegalArgumentException("The mapping target '" + targetFieldExpression
 					+ "' is not a parseable property expression", e);
 		}
 		Mapping mapping = new Mapping(sourceExp, targetExp);
@@ -88,33 +89,33 @@ public class SpelMapper implements Mapper<Object, Object> {
 		return mapping;
 	}
 
-	public void map(Object source, Object target) {
+	public Object map(Object source, Object target) {
 		EvaluationContext sourceContext = getMappingContext(source);
 		EvaluationContext targetContext = getMappingContext(target);
 		List<MappingFailure> failures = new LinkedList<MappingFailure>();
 		for (Mapping mapping : this.mappings) {
 			mapping.map(sourceContext, targetContext, failures);
 		}
-		Set<Mapping> autoMappings = getAutoMappings(source, target);
+		Set<Mapping> autoMappings = getAutoMappings(sourceContext, targetContext);
 		for (Mapping mapping : autoMappings) {
 			mapping.map(sourceContext, targetContext, failures);
 		}
 		if (!failures.isEmpty()) {
 			throw new MappingException(failures);
 		}
+		return target;
 	}
 
 	private EvaluationContext getMappingContext(Object object) {
 		return mappableTypeFactory.getMappableType(object).getEvaluationContext(object, this.conversionService);
 	}
 
-	private Set<Mapping> getAutoMappings(Object source, Object target) {
+	private Set<Mapping> getAutoMappings(EvaluationContext sourceContext, EvaluationContext targetContext) {
 		if (this.autoMappingEnabled) {
 			Set<Mapping> autoMappings = new LinkedHashSet<Mapping>();
-			Set<String> sourceFields = getMappableFields(source);
-			Set<String> targetFields = getMappableFields(target);
+			Set<String> sourceFields = getMappableFields(sourceContext.getRootObject().getValue());
 			for (String field : sourceFields) {
-				if (!explicitlyMapped(field) && targetFields.contains(field)) {
+				if (!explicitlyMapped(field)) {
 					Expression sourceExpression;
 					Expression targetExpression;
 					try {
@@ -129,8 +130,13 @@ public class SpelMapper implements Mapper<Object, Object> {
 						throw new IllegalArgumentException("The mapping target '" + field
 								+ "' is not a parseable value expression", e);
 					}
-					Mapping mapping = new Mapping(sourceExpression, targetExpression);
-					autoMappings.add(mapping);
+					try {
+						if (targetExpression.isWritable(targetContext)) {
+							autoMappings.add(new Mapping(sourceExpression, targetExpression));
+						}
+					} catch (EvaluationException e) {
+
+					}
 				}
 			}
 			return autoMappings;
@@ -145,7 +151,7 @@ public class SpelMapper implements Mapper<Object, Object> {
 
 	private boolean explicitlyMapped(String field) {
 		for (Mapping mapping : this.mappings) {
-			if (mapping.getSourceExpressionString().equals(field)) {
+			if (mapping.getSourceExpressionString().startsWith(field)) {
 				return true;
 			}
 		}

org.springframework.context/src/test/java/org/springframework/mapping/support/SpelMapperTests.java

@@ -1,6 +1,7 @@
 package org.springframework.mapping.support;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -31,15 +32,14 @@ public class SpelMapperTests {
 
 	@Test
 	public void mapExplicit() throws MappingException {
-		mapper.setAutoMappingEnabled(false);
-		mapper.addMapping("name");
-
 		Map<String, Object> source = new HashMap<String, Object>();
 		source.put("name", "Keith");
 		source.put("age", 31);
 
 		Person target = new Person();
 
+		mapper.setAutoMappingEnabled(false);
+		mapper.addMapping("name");
 		mapper.map(source, target);
 
 		assertEquals("Keith", target.name);
@@ -48,8 +48,6 @@ public class SpelMapperTests {
 
 	@Test
 	public void mapAutomaticWithExplictOverrides() {
-		mapper.addMapping("test", "age");
-
 		Map<String, Object> source = new HashMap<String, Object>();
 		source.put("name", "Keith");
 		source.put("test", "3");
@@ -57,6 +55,7 @@ public class SpelMapperTests {
 
 		Person target = new Person();
 
+		mapper.addMapping("test", "age");
 		mapper.map(source, target);
 
 		assertEquals("Keith", target.name);
@@ -65,15 +64,29 @@ public class SpelMapperTests {
 	}
 
 	@Test
-	public void mapSameSourceFieldToMultipleTargets() {
-		mapper.addMapping("test", "name");
-		mapper.addMapping("test", "favoriteSport");
+	public void mapAutomaticIgnoreUnknownField() {
+		Map<String, Object> source = new HashMap<String, Object>();
+		source.put("name", "Keith");
+		source.put("age", 31);
+		source.put("unknown", "foo");
 
+		Person target = new Person();
+
+		mapper.map(source, target);
+
+		assertEquals("Keith", target.name);
+		assertEquals(31, target.age);
+	}
+
+	@Test
+	public void mapSameSourceFieldToMultipleTargets() {
 		Map<String, Object> source = new HashMap<String, Object>();
 		source.put("test", "FOOTBALL");
 
 		Person target = new Person();
 
+		mapper.addMapping("test", "name");
+		mapper.addMapping("test", "favoriteSport");
 		mapper.map(source, target);
 
 		assertEquals("FOOTBALL", target.name);
@@ -92,7 +105,6 @@ public class SpelMapperTests {
 
 		mapper.addMapping("fullName", "name");
 		mapper.addMapping("sport", "favoriteSport");
-
 		mapper.map(source, target);
 
 		assertEquals("Keith Donald", target.name);
@@ -100,24 +112,46 @@ public class SpelMapperTests {
 		assertEquals(Sport.FOOTBALL, target.favoriteSport);
 	}
 
+	@Test
+	public void mapBeanDeep() {
+		PersonDto source = new PersonDto();
+		source.age = "0";
+		NestedDto nested = new NestedDto();
+		nested.foo = "bar";
+		source.setNested(nested);
+
+		Person target = new Person();
+
+		mapper.addMapping("nested.foo", "nested.foo");
+		mapper.map(source, target);
+
+		assertEquals("bar", target.nested.foo);
+	}
+
 	@Test
 	public void mapBeanNested() {
 		PersonDto source = new PersonDto();
 		source.setFullName("Keith Donald");
 		source.setAge("31");
 		source.setSport("FOOTBALL");
+		NestedDto nested = new NestedDto();
+		nested.foo = "bar";
+		source.setNested(nested);
 
 		Person target = new Person();
 
-		mapper.addMapping("fullName", "nested.fullName");
-		mapper.addMapping("age", "nested.age");
-		mapper.addMapping("sport", "nested.sport");
-
+		mapper.addMapping("fullName", "name");
+		mapper.addMapping("sport", "favoriteSport");
+		mapper.addMapping("nested", "nested").setConverter(new Converter<NestedDto, Nested>() {
+			public Nested convert(NestedDto source) {
+				return (Nested) new SpelMapper().map(source, new Nested());
+			}
+		});
 		mapper.map(source, target);
 
-		assertEquals("Keith Donald", target.getNested().getFullName());
-		assertEquals("31", target.nested.age);
-		assertEquals("FOOTBALL", target.nested.sport);
+		assertEquals("Keith Donald", target.name);
+		assertEquals(31, target.age);
+		assertEquals(Sport.FOOTBALL, target.favoriteSport);
 	}
 
 	@Test
@@ -132,13 +166,30 @@ public class SpelMapperTests {
 
 		mapper.setAutoMappingEnabled(false);
 		mapper.addMapping("sports", "favoriteSports");
-
 		mapper.map(source, target);
 
 		assertEquals(Sport.FOOTBALL, target.favoriteSports.get(0));
 		assertEquals(Sport.BASKETBALL, target.favoriteSports.get(1));
 	}
 
+	@Test
+	public void mapListFlatten() {
+		PersonDto source = new PersonDto();
+		List<String> sports = new ArrayList<String>();
+		sports.add("FOOTBALL");
+		sports.add("BASKETBALL");
+		source.setSports(sports);
+
+		Person target = new Person();
+
+		mapper.setAutoMappingEnabled(false);
+		mapper.addMapping("sports[0]", "favoriteSport");
+		mapper.map(source, target);
+
+		assertEquals(Sport.FOOTBALL, target.favoriteSport);
+		assertNull(target.favoriteSports);
+	}
+
 	@Test
 	public void mapMap() {
 		PersonDto source = new PersonDto();
@@ -187,7 +238,7 @@ public class SpelMapperTests {
 	public void mapFailure() {
 		Map<String, Object> source = new HashMap<String, Object>();
 		source.put("name", "Keith");
-		source.put("age", "bogus");
+		source.put("age", "invalid");
 		Person target = new Person();
 		try {
 			mapper.map(source, target);
@@ -208,7 +259,7 @@ public class SpelMapperTests {
 
 		private Map<String, String> friendRankings;
 
-		private NestedDto nestedDto;
+		private NestedDto nested;
 
 		public String getFullName() {
 			return fullName;
@@ -250,12 +301,12 @@ public class SpelMapperTests {
 			this.friendRankings = friendRankings;
 		}
 
-		public NestedDto getNestedDto() {
-			return nestedDto;
+		public NestedDto getNested() {
+			return nested;
 		}
 
-		public void setNestedDto(NestedDto nestedDto) {
-			this.nestedDto = nestedDto;
+		public void setNested(NestedDto nested) {
+			this.nested = nested;
 		}
 
 	}
@@ -277,7 +328,7 @@ public class SpelMapperTests {
 
 		private Sport favoriteSport;
 
-		private PersonDto nested;
+		private Nested nested;
 
 		// private Person cyclic;
 
@@ -317,11 +368,11 @@ public class SpelMapperTests {
 			this.favoriteSport = favoriteSport;
 		}
 
-		public PersonDto getNested() {
+		public Nested getNested() {
 			return nested;
 		}
 
-		public void setNested(PersonDto nested) {
+		public void setNested(Nested nested) {
 			this.nested = nested;
 		}
 
@@ -364,6 +415,20 @@ public class SpelMapperTests {
 		}
 	}
 
+	public static class Nested {
+
+		private String foo;
+
+		public String getFoo() {
+			return foo;
+		}
+
+		public void setFoo(String foo) {
+			this.foo = foo;
+		}
+
+	}
+
 	public enum Sport {
 		FOOTBALL, BASKETBALL
 	}

org.springframework.core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -159,6 +159,14 @@ public class TypeDescriptor {
 		}
 	}
 
+	/**
+	 * Is this type a primitive type?
+	 */
+	public boolean isPrimitive() {
+		Class<?> type = getType();
+		return (type != null && type.isPrimitive());
+	}
+
 	/**
 	 * Is this type an array type?
 	 */
@@ -195,7 +203,7 @@ public class TypeDescriptor {
 				return TypeDescriptor.valueOf(getCollectionElementType());
 			} else {
 				return TypeDescriptor.NULL;
-			}			
+			}
 		}
 	}
 

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

@@ -16,6 +16,8 @@
 
 package org.springframework.core.convert.support;
 
+import java.util.Collection;
+import java.util.Map;
 
 /**
  * Default implementation of a conversion service. Will automatically register <i>from string</i>
@@ -31,6 +33,21 @@ public class DefaultConversionService extends GenericConversionService {
 	 * Create a new default conversion service, installing the default converters.
 	 */
 	public DefaultConversionService() {
+		addGenericConverter(Object[].class, Object[].class, new ArrayToArrayConverter(this));
+		addGenericConverter(Object[].class, Collection.class, new ArrayToCollectionConverter(this));
+		addGenericConverter(Object[].class, Map.class, new ArrayToMapConverter(this));
+		addGenericConverter(Object[].class, Object.class, new ArrayToObjectConverter(this));
+		addGenericConverter(Collection.class, Collection.class, new CollectionToCollectionConverter(this));
+		addGenericConverter(Collection.class, Object[].class, new CollectionToArrayConverter(this));
+		addGenericConverter(Collection.class, Map.class, new CollectionToMapConverter(this));
+		addGenericConverter(Collection.class, Object.class, new CollectionToObjectConverter(this));
+		addGenericConverter(Map.class, Map.class, new MapToMapConverter(this));
+		addGenericConverter(Map.class, Object[].class, new MapToArrayConverter(this));
+		addGenericConverter(Map.class, Collection.class, new MapToCollectionConverter(this));
+		addGenericConverter(Map.class, Object.class, new MapToObjectConverter(this));
+		addGenericConverter(Object.class, Object[].class, new ObjectToArrayConverter(this));
+		addGenericConverter(Object.class, Collection.class, new ObjectToCollectionConverter(this));
+		addGenericConverter(Object.class, Map.class, new ObjectToMapConverter(this));
 		addConverter(new StringToBooleanConverter());
 		addConverter(new StringToCharacterConverter());
 		addConverter(new StringToLocaleConverter());

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

@@ -16,6 +16,8 @@
 
 package org.springframework.core.convert.support;
 
+import static org.springframework.core.convert.support.ConversionUtils.invokeConverter;
+
 import java.lang.reflect.Array;
 import java.util.Collection;
 import java.util.Collections;
@@ -25,6 +27,7 @@ import java.util.Map;
 import java.util.Set;
 
 import org.springframework.core.GenericTypeResolver;
+import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
@@ -32,13 +35,11 @@ import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.converter.ConverterFactory;
 import org.springframework.core.convert.converter.ConverterInfo;
 import org.springframework.core.convert.converter.ConverterRegistry;
-import static org.springframework.core.convert.support.ConversionUtils.*;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
 /**
- * Base implementation of a conversion service.
- *
+ * Base ConversionService implementation suitable for use in most environments.
  * @author Keith Donald
  * @author Juergen Hoeller
  * @since 3.0
@@ -63,8 +64,12 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		}
 	};
 
-
+	/**
+	 * Create a new GenericConversionService.
+	 * Generic converters for Collection types are registered.
+	 */
 	public GenericConversionService() {
+		// TODO should these only be registered in DefaultConversionService?
 		addGenericConverter(Object[].class, Object[].class, new ArrayToArrayConverter(this));
 		addGenericConverter(Object[].class, Collection.class, new ArrayToCollectionConverter(this));
 		addGenericConverter(Object[].class, Map.class, new ArrayToMapConverter(this));
@@ -82,7 +87,6 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		addGenericConverter(Object.class, Map.class, new ObjectToMapConverter(this));
 	}
 
-
 	/**
 	 * Registers the converters in the set provided.
 	 * JavaBean-friendly alternative to calling {@link #addConverter(Converter)}.
@@ -113,13 +117,12 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	}
 
 	/**
-	 * Returns the parent of this conversion service. Could be null.
+	 * Returns the parent of this conversion service. May be null.
 	 */
 	public ConversionService getParent() {
 		return this.parent;
 	}
 
-
 	// implementing ConverterRegistry
 
 	public void addConverter(Converter<?, ?> converter) {
@@ -130,7 +133,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		}
 		Class sourceType = typeInfo[0];
 		Class targetType = typeInfo[1];
-		getSourceMap(sourceType).put(targetType, new ConverterGenericConverter(converter));
+		getSourceMap(sourceType).put(targetType, new ConverterAdapter(converter));
 	}
 
 	public void addConverterFactory(ConverterFactory<?, ?> converterFactory) {
@@ -141,43 +144,37 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		}
 		Class sourceType = typeInfo[0];
 		Class targetType = typeInfo[1];
-		getSourceMap(sourceType).put(targetType, new ConverterFactoryGenericConverter(converterFactory));
+		getSourceMap(sourceType).put(targetType, new ConverterFactoryAdapter(converterFactory));
 	}
 
 	public void removeConvertible(Class<?> sourceType, Class<?> targetType) {
 		getSourceMap(sourceType).remove(targetType);
 	}
 
-
 	// implementing ConversionService
 
 	public boolean canConvert(Class<?> sourceType, Class<?> targetType) {
 		return canConvert(TypeDescriptor.valueOf(sourceType), TypeDescriptor.valueOf(targetType));
 	}
 
-	@SuppressWarnings("unchecked")
 	public <T> T convert(Object source, Class<T> targetType) {
-		Assert.notNull(targetType, "The targetType to convert to is required");
 		return (T) convert(source, TypeDescriptor.forObject(source), TypeDescriptor.valueOf(targetType));
 	}
 
 	public boolean canConvert(TypeDescriptor sourceType, TypeDescriptor targetType) {
-		Assert.notNull(sourceType, "The sourceType to convert from is required");
-		Assert.notNull(targetType, "The targetType to convert to is required");
-		if (targetType == TypeDescriptor.NULL) {
+		assertNotNull(sourceType, targetType);
+		if (sourceType == TypeDescriptor.NULL || targetType == TypeDescriptor.NULL) {
 			return true;
 		}
 		return getConverter(sourceType, targetType) != null;
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
-		Assert.notNull(sourceType, "The sourceType to convert to is required");
-		Assert.notNull(targetType, "The targetType to convert to is required");
-		if (source == null) {
-			return convertNull(sourceType, targetType);
+		assertNotNull(sourceType, targetType);
+		if (sourceType == TypeDescriptor.NULL) {
+			Assert.isTrue(source == null, "The source must be null if sourceType == TypeDescriptor.NULL");
+			return convertNullSource(sourceType, targetType);
 		}
-		Assert.isTrue(sourceType != TypeDescriptor.NULL,
-				"The source TypeDescriptor must not be TypeDescriptor.NULL when source != null");
 		if (targetType == TypeDescriptor.NULL) {
 			return null;
 		}
@@ -188,7 +185,6 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		return invokeConverter(converter, source, sourceType, targetType);
 	}
 
-	
 	// subclassing hooks
 
 	/**
@@ -197,19 +193,25 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	 * @param targetType the target type to convert to
 	 * @param converter the generic converter.
 	 */
+	// TODO should this be public?
 	protected void addGenericConverter(Class<?> sourceType, Class<?> targetType, GenericConverter converter) {
 		getSourceMap(sourceType).put(targetType, converter);
 	}
 
 	/**
-	 * Hook method to convert a null value.
-	 * Default implementation simply returns <code>null</code>.
-	 * Subclasses may override to return a custom null objects for specific target types.
-	 * @param sourceType the sourceType
-	 * @param targetType the tagetType
-	 * @return the null object
+	 * Hook method to convert a null source.
+	 * Default implementation returns <code>null</code>.
+	 * Throws a {@link ConversionFailedException} if the targetType is a primitive type, as null cannot be assigned to a primitive type. 
+	 * Subclasses may override to return custom null objects for specific target types.
+	 * @param sourceType the sourceType to convert from
+	 * @param targetType the targetType to convert to
+	 * @return the converted null object
 	 */
-	protected Object convertNull(TypeDescriptor sourceType, TypeDescriptor targetType) {
+	protected Object convertNullSource(TypeDescriptor sourceType, TypeDescriptor targetType) {
+		if (targetType.isPrimitive()) {
+			throw new ConversionFailedException(sourceType, targetType, null, new IllegalArgumentException(
+					"A null value cannot be assigned to a primitive type"));
+		}
 		return null;
 	}
 
@@ -228,23 +230,24 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		GenericConverter converter = findConverterByClassPair(sourceType.getObjectType(), targetType.getObjectType());
 		if (converter != null) {
 			return converter;
-		}
-		else if (this.parent != null && this.parent.canConvert(sourceType, targetType)) {
+		} else if (this.parent != null && this.parent.canConvert(sourceType, targetType)) {
 			return this.parentConverterAdapter;
-		}
-		else {
+		} else {
 			if (sourceType.isAssignableTo(targetType)) {
 				return NO_OP_CONVERTER;
-			}
-			else {
+			} else {
 				return null;
 			}
 		}
 	}
 
-	
 	// internal helpers
 
+	private void assertNotNull(TypeDescriptor sourceType, TypeDescriptor targetType) {
+		Assert.notNull(sourceType, "The sourceType to convert to is required");
+		Assert.notNull(targetType, "The targetType to convert to is required");
+	}
+
 	private Class[] getRequiredTypeInfo(Object converter, Class genericIfc) {
 		Class[] typeInfo = new Class[2];
 		if (converter instanceof ConverterInfo) {
@@ -252,8 +255,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 			typeInfo[0] = info.getSourceType();
 			typeInfo[1] = info.getTargetType();
 			return typeInfo;
-		}
-		else {
+		} else {
 			return GenericTypeResolver.resolveTypeArguments(converter.getClass(), genericIfc);
 		}
 	}
@@ -276,8 +278,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 			}
 			Map<Class, GenericConverter> objectConverters = getConvertersForSource(Object.class);
 			return getConverter(objectConverters, targetType);
-		}
-		else {
+		} else {
 			LinkedList<Class> classQueue = new LinkedList<Class>();
 			classQueue.addFirst(sourceType);
 			while (!classQueue.isEmpty()) {
@@ -292,8 +293,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 					if (componentType.getSuperclass() != null) {
 						classQueue.addFirst(Array.newInstance(componentType.getSuperclass(), 0).getClass());
 					}
-				}
-				else {
+				} else {
 					if (currentClass.getSuperclass() != null) {
 						classQueue.addFirst(currentClass.getSuperclass());
 					}
@@ -340,8 +340,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 				}
 			}
 			return converters.get(Object.class);
-		}
-		else {
+		} else {
 			LinkedList<Class> classQueue = new LinkedList<Class>();
 			classQueue.addFirst(targetType);
 			while (!classQueue.isEmpty()) {
@@ -355,8 +354,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 					if (componentType.getSuperclass() != null) {
 						classQueue.addFirst(Array.newInstance(componentType.getSuperclass(), 0).getClass());
 					}
-				}
-				else {
+				} else {
 					if (currentClass.getSuperclass() != null) {
 						classQueue.addFirst(currentClass.getSuperclass());
 					}
@@ -370,4 +368,36 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		}
 	}
 
+	private final class ConverterAdapter implements GenericConverter {
+
+		private final Converter converter;
+
+		public ConverterAdapter(Converter converter) {
+			this.converter = converter;
+		}
+
+		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
+			if (source == null) {
+				return convertNullSource(sourceType, targetType);
+			}
+			return this.converter.convert(source);
+		}
+	}
+
+	private final class ConverterFactoryAdapter implements GenericConverter {
+
+		private final ConverterFactory converterFactory;
+
+		public ConverterFactoryAdapter(ConverterFactory converterFactory) {
+			this.converterFactory = converterFactory;
+		}
+
+		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
+			if (source == null) {
+				return convertNullSource(sourceType, targetType);
+			}
+			return this.converterFactory.getConverter(targetType.getObjectType()).convert(source);
+		}
+	}
+
 }

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

@@ -91,14 +91,13 @@ public class GenericConversionServiceTests {
 		assertNull(conversionService.convert(null, Integer.class));
 	}
 
-	@Test(expected = IllegalArgumentException.class)
 	public void convertNullTargetClass() {
-		assertEquals("3", conversionService.convert("3", (Class<?>) null));
+		assertNull(conversionService.convert("3", (Class<?>) null));
 	}
 
 	@Test
 	public void convertNullTypeDescriptor() {
-		assertEquals(null, conversionService.convert(3, TypeDescriptor.valueOf(String.class), TypeDescriptor.NULL));
+		assertNull(conversionService.convert("3", TypeDescriptor.valueOf(String.class), TypeDescriptor.NULL));
 	}
 
 	@Test
@@ -132,6 +131,7 @@ public class GenericConversionServiceTests {
 
 	@Test
 	public void convertArrayToArray() {
+		conversionService.addGenericConverter(Object[].class, Object[].class, new ArrayToArrayConverter(conversionService));
 		conversionService.addConverterFactory(new StringToNumberConverterFactory());
 		Integer[] result = conversionService.convert(new String[] { "1", "2", "3" }, Integer[].class);
 		assertEquals(new Integer(1), result[0]);

org.springframework.expression/src/main/java/org/springframework/expression/spel/support/StandardTypeConverter.java

@@ -28,9 +28,8 @@ import org.springframework.expression.spel.SpelMessage;
 import org.springframework.util.Assert;
 
 /**
- * Default implementation of the {@link TypeConverter} interface,
- * delegating to a core Spring {@link ConversionService}.
- *
+ * Default implementation of the {@link TypeConverter} interface, delegating to a core Spring {@link ConversionService}.
+ * 
  * @author Juergen Hoeller
  * @author Andy Clement
  * @since 3.0
@@ -56,12 +55,12 @@ public class StandardTypeConverter implements TypeConverter {
 	public Object convertValue(Object value, TypeDescriptor typeDescriptor) throws EvaluationException {
 		try {
 			return this.conversionService.convert(value, TypeDescriptor.forObject(value), typeDescriptor);
-		}
-		catch (ConverterNotFoundException cenfe) {
-			throw new SpelEvaluationException(cenfe, SpelMessage.TYPE_CONVERSION_ERROR, value.getClass(), typeDescriptor.asString());
-		}
-		catch (ConversionException ce) {
-			throw new SpelEvaluationException(ce, SpelMessage.TYPE_CONVERSION_ERROR, value.getClass(), typeDescriptor.asString());
+		} catch (ConverterNotFoundException cenfe) {
+			throw new SpelEvaluationException(cenfe, SpelMessage.TYPE_CONVERSION_ERROR, value != null ? value
+					.getClass() : null, typeDescriptor.asString());
+		} catch (ConversionException ce) {
+			throw new SpelEvaluationException(ce, SpelMessage.TYPE_CONVERSION_ERROR, value != null ? value.getClass()
+					: null, typeDescriptor.asString());
 		}
 	}