revised GenericConverter's "getConvertibleTypes()" signature to return Set of ConvertiblePair

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@2611 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.core/src/main/java/org/springframework/core/convert/converter/GenericConverter.java

@@ -16,19 +16,26 @@
 
 package org.springframework.core.convert.converter;
 
+import java.util.Set;
+
 import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.util.Assert;
 
 /**
  * Generic converter interface for converting between two or more types.
- * <p>
- * This is the most flexible of the Converter SPI interfaces, but also the most complex.
- * It is flexible in that a GenericConverter may support converting between multiple source/target type pairs (see {@link #getConvertibleTypes()}.
- * In addition, GenericConverter implementations have access to source/target {@link TypeDescriptor field context} during the type conversion process.
- * This allows for resolving source and target field metadata such as annotations and generics information, which can be used influence the conversion logic.
- * <p>
- * This interface should generally not be used when the simpler {@link Converter} or {@link ConverterFactory} interfaces are sufficient.
+ *
+ * <p>This is the most flexible of the Converter SPI interfaces, but also the most complex.
+ * It is flexible in that a GenericConverter may support converting between multiple source/target
+ * type pairs (see {@link #getConvertibleTypes()}. In addition, GenericConverter implementations
+ * have access to source/target {@link TypeDescriptor field context} during the type conversion process.
+ * This allows for resolving source and target field metadata such as annotations and generics
+ * information, which can be used influence the conversion logic.
+ *
+ * <p>This interface should generally not be used when the simpler {@link Converter} or
+ * {@link ConverterFactory} interfaces are sufficient.
  *
  * @author Keith Donald
+ * @author Juergen Hoeller
  * @since 3.0
  * @see TypeDescriptor
  * @see Converter
@@ -37,11 +44,10 @@ import org.springframework.core.convert.TypeDescriptor;
 public interface GenericConverter {
 
 	/**
-	 * The source and target types this converter can convert between.
-	 * Each entry in the returned array is a convertible source-to-target type pair, also expressed as an array.
-	 * For each pair, the first array element is a sourceType that can be converted from, and the second array element is a targetType that can be converted to.
+	 * Return the source and target types which this converter can convert between.
+	 * <p>Each entry is a convertible source-to-target type pair.
 	 */
-	public Class<?>[][] getConvertibleTypes();
+	Set<ConvertiblePair> getConvertibleTypes();
 
 	/**
 	 * Convert the source to the targetType described by the TypeDescriptor.
@@ -52,4 +58,35 @@ public interface GenericConverter {
 	 */
 	Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType);
 
+
+	/**
+	 * Holder for a source-to-target class pair.
+	 */
+	public static final class ConvertiblePair {
+
+		private final Class<?> sourceType;
+
+		private final Class<?> targetType;
+
+		/**
+		 * Create a new source-to-target pair.
+		 * @param sourceType the source type
+		 * @param targetType the target type
+		 */
+		public ConvertiblePair(Class<?> sourceType, Class<?> targetType) {
+			Assert.notNull(sourceType, "Source type must not be null");
+			Assert.notNull(targetType, "Target type must not be null");
+			this.sourceType = sourceType;
+			this.targetType = targetType;
+		}
+
+		public Class<?> getSourceType() {
+			return this.sourceType;
+		}
+
+		public Class<?> getTargetType() {
+			return this.targetType;
+		}
+	}
+
 }

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

@@ -17,6 +17,8 @@
 package org.springframework.core.convert.support;
 
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
@@ -35,9 +37,9 @@ final class ArrayToArrayConverter implements GenericConverter {
 	public ArrayToArrayConverter(GenericConversionService conversionService) {
 		this.helperConverter = new CollectionToArrayConverter(conversionService);
 	}
-	
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Object[].class, Object[].class } };
+
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object[].class, Object[].class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {		

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

@@ -16,15 +16,16 @@
 
 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;
+import java.util.Set;
 
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from an array to a collection.
@@ -40,8 +41,8 @@ final class ArrayToCollectionConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Object[].class, Collection.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object[].class, Collection.class));
 	}
 
 	@SuppressWarnings("unchecked")

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

@@ -17,7 +17,9 @@
 package org.springframework.core.convert.support;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Map;
+import java.util.Set;
 
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
@@ -37,8 +39,8 @@ final class ArrayToMapConverter implements GenericConverter {
 		this.helperConverter = new CollectionToMapConverter(conversionService);
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Object[].class, Map.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object[].class, Map.class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -17,6 +17,8 @@
 package org.springframework.core.convert.support;
 
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
@@ -36,8 +38,8 @@ final class ArrayToObjectConverter implements GenericConverter {
 		this.helperConverter = new CollectionToObjectConverter(conversionService);
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] {{Object[].class, Object.class}};
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object[].class, Object.class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -16,16 +16,16 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.getElementType;
-import static org.springframework.core.convert.support.ConversionUtils.invokeConverter;
-
 import java.lang.reflect.Array;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Iterator;
+import java.util.Set;
 
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from a Collection to an array.
@@ -41,8 +41,8 @@ final class CollectionToArrayConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Collection.class, Object[].class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Collection.class, Object[].class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -16,15 +16,15 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.getElementType;
-import static org.springframework.core.convert.support.ConversionUtils.invokeConverter;
-
 import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from a source Collection to target Collection type.
@@ -40,8 +40,8 @@ final class CollectionToCollectionConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Collection.class, Collection.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Collection.class, Collection.class));
 	}
 
 	@SuppressWarnings("unchecked")

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

@@ -16,14 +16,15 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.getElementType;
-
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Map;
+import java.util.Set;
 
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from a Collection to a Map.
@@ -39,8 +40,8 @@ final class CollectionToMapConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Collection.class, Map.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Collection.class, Map.class));
 	}
 
 	@SuppressWarnings("unchecked")

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

@@ -16,14 +16,14 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.getElementType;
-import static org.springframework.core.convert.support.ConversionUtils.invokeConverter;
-
 import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from a Collection to a single Object.
@@ -41,8 +41,8 @@ final class CollectionToObjectConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Collection.class, Object.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Collection.class, Object.class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -16,9 +16,16 @@
 
 package org.springframework.core.convert.support;
 
+import java.util.Set;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.core.convert.converter.ConverterFactory;
+import org.springframework.core.convert.converter.ConverterRegistry;
+import org.springframework.core.convert.converter.GenericConverter;
 
 /**
- * A factory for common ConversionService configurations.
+ * A factory for common {@link org.springframework.core.convert.ConversionService}
+ * configurations.
  *
  * @author Keith Donald
  * @author Juergen Hoeller
@@ -67,4 +74,30 @@ public abstract class ConversionServiceFactory {
 		conversionService.addGenericConverter(new IdToEntityConverter(conversionService));
 	}
 
+	/**
+	 * Register the given converter objects with the given target registry.
+	 * @param converters the converter objects: implementing {@link Converter},
+	 * {@link ConverterFactory}, or {@link GenericConverter}
+	 * @param registry the target registry to register with
+	 */
+	public static void registerConverters(Set<Object> converters, ConverterRegistry registry) {
+		if (converters != null) {
+			for (Object converter : converters) {
+				if (converter instanceof Converter<?, ?>) {
+					registry.addConverter((Converter<?, ?>) converter);
+				}
+				else if (converter instanceof ConverterFactory<?, ?>) {
+					registry.addConverterFactory((ConverterFactory<?, ?>) converter);
+				}
+				else if (converter instanceof GenericConverter) {
+					registry.addGenericConverter((GenericConverter) converter);
+				}
+				else {
+					throw new IllegalArgumentException("Each converter object must implement one of the " +
+							"Converter, ConverterFactory, or GenericConverter interfaces");
+				}
+			}
+		}
+	}
+
 }

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

@@ -24,6 +24,7 @@ import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -55,7 +56,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	private static final Log logger = LogFactory.getLog(GenericConversionService.class);
 
 	private static final GenericConverter NO_OP_CONVERTER = new GenericConverter() {
-		public Class<?>[][] getConvertibleTypes() {
+		public Set<ConvertiblePair> getConvertibleTypes() {
 			return null;
 		}
 		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
@@ -71,7 +72,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	// implementing ConverterRegistry
 
 	public void addConverter(Converter<?, ?> converter) {
-		Class<?>[] typeInfo = getRequiredTypeInfo(converter, Converter.class);
+		GenericConverter.ConvertiblePair typeInfo = getRequiredTypeInfo(converter, Converter.class);
 		if (typeInfo == null) {
 			throw new IllegalArgumentException("Unable to the determine sourceType <S> and targetType <T> which " +
 							"your Converter<S, T> converts between; declare these generic types.");
@@ -80,7 +81,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	}
 
 	public void addConverterFactory(ConverterFactory<?, ?> converterFactory) {
-		Class<?>[] typeInfo = getRequiredTypeInfo(converterFactory, ConverterFactory.class);
+		GenericConverter.ConvertiblePair typeInfo = getRequiredTypeInfo(converterFactory, ConverterFactory.class);
 		if (typeInfo == null) {
 			throw new IllegalArgumentException("Unable to the determine sourceType <S> and targetRangeType R which " +
 					"your ConverterFactory<S, R> converts between; declare these generic types.");
@@ -89,9 +90,9 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	}
 
 	public void addGenericConverter(GenericConverter converter) {
-		Class<?>[][] convertibleTypes = converter.getConvertibleTypes();
-		for (Class<?>[] convertibleType : convertibleTypes) {
-			getMatchableConvertersList(convertibleType[0], convertibleType[1]).add(converter);
+		Set<GenericConverter.ConvertiblePair> convertibleTypes = converter.getConvertibleTypes();
+		for (GenericConverter.ConvertiblePair convertibleType : convertibleTypes) {
+			getMatchableConvertersList(convertibleType.getSourceType(), convertibleType.getTargetType()).add(converter);
 		}
 	}
 
@@ -213,8 +214,9 @@ public class GenericConversionService implements ConversionService, ConverterReg
 
 	// internal helpers
 
-	private Class<?>[] getRequiredTypeInfo(Object converter, Class<?> genericIfc) {
-		return GenericTypeResolver.resolveTypeArguments(converter.getClass(), genericIfc);
+	private GenericConverter.ConvertiblePair getRequiredTypeInfo(Object converter, Class<?> genericIfc) {
+		Class[] args = GenericTypeResolver.resolveTypeArguments(converter.getClass(), genericIfc);
+		return (args != null ? new GenericConverter.ConvertiblePair(args[0], args[1]) : null);
 	}
 
 	private MatchableConverters getMatchableConvertersList(Class<?> sourceType, Class<?> targetType) {
@@ -370,17 +372,17 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	@SuppressWarnings("unchecked")
 	private final class ConverterAdapter implements GenericConverter {
 
-		private final Class<?>[] typeInfo;
+		private final ConvertiblePair typeInfo;
 
 		private final Converter converter;
 
-		public ConverterAdapter(Class<?>[] typeInfo, Converter<?, ?> converter) {
+		public ConverterAdapter(ConvertiblePair typeInfo, Converter<?, ?> converter) {
 			this.converter = converter;
 			this.typeInfo = typeInfo;
 		}
 
-		public Class<?>[][] getConvertibleTypes() {
-			return new Class[][] {this.typeInfo};
+		public Set<ConvertiblePair> getConvertibleTypes() {
+			return Collections.singleton(this.typeInfo);
 		}
 
 		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
@@ -391,7 +393,8 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		}
 
 		public String toString() {
-			return this.typeInfo[0].getName() + " -> " + this.typeInfo[1].getName() + " : " + this.converter.toString(); 
+			return this.typeInfo.getSourceType().getName() + " -> " + this.typeInfo.getTargetType().getName() +
+					" : " + this.converter.toString();
 		}
 	}
 
@@ -399,17 +402,17 @@ public class GenericConversionService implements ConversionService, ConverterReg
 	@SuppressWarnings("unchecked")
 	private final class ConverterFactoryAdapter implements GenericConverter {
 
-		private final Class<?>[] typeInfo;
+		private final ConvertiblePair typeInfo;
 
 		private final ConverterFactory converterFactory;
 
-		public ConverterFactoryAdapter(Class<?>[] typeInfo, ConverterFactory<?, ?> converterFactory) {
+		public ConverterFactoryAdapter(ConvertiblePair typeInfo, ConverterFactory<?, ?> converterFactory) {
 			this.converterFactory = converterFactory;
 			this.typeInfo = typeInfo;
 		}
 
-		public Class<?>[][] getConvertibleTypes() {
-			return new Class[][] {this.typeInfo};
+		public Set<ConvertiblePair> getConvertibleTypes() {
+			return Collections.singleton(this.typeInfo);
 		}
 
 		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
@@ -420,8 +423,8 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		}
 
 		public String toString() {
-			return this.typeInfo[0].getName() + " -> " + this.typeInfo[1].getName() + " : " +
-					this.converterFactory.toString();
+			return this.typeInfo.getSourceType().getName() + " -> " + this.typeInfo.getTargetType().getName() +
+					" : " + this.converterFactory.toString();
 		}
 	}
 

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

@@ -13,10 +13,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.core.convert.support;
 
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.ConditionalGenericConverter;
@@ -24,8 +27,12 @@ import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 
 /**
- * Converts an entity identifier to a entity reference by calling a static finder method on the target entity type.
- * For this converter to match, the finder method must be public, static, have the signature 'find[EntityName]([IdType])', and return an instance of the desired entity type.
+ * Converts an entity identifier to a entity reference by calling a static finder method
+ * on the target entity type.
+ *
+ * <p>For this converter to match, the finder method must be public, static, have the signature
+ * <code>find[EntityName]([IdType])</code>, and return an instance of the desired entity type.
+ *
  * @author Keith Donald
  * @since 3.0
  */
@@ -37,8 +44,8 @@ final class IdToEntityConverter implements ConditionalGenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class[][] { { Object.class, Object.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object.class, Object.class));
 	}
 
 	public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -16,8 +16,10 @@
 
 package org.springframework.core.convert.support;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
@@ -39,8 +41,8 @@ final class MapToArrayConverter implements GenericConverter {
 		this.collectionToArrayHelperConverter = new CollectionToArrayConverter(conversionService);
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Map.class, Object[].class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Map.class, Object[].class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -16,14 +16,15 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.getMapEntryTypes;
-
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Map;
+import java.util.Set;
 
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from a Map to a Collection.
@@ -39,8 +40,8 @@ final class MapToCollectionConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Map.class, Collection.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Map.class, Collection.class));
 	}
 
 	@SuppressWarnings("unchecked")

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

@@ -16,13 +16,14 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.getMapEntryTypes;
-
+import java.util.Collections;
 import java.util.Map;
+import java.util.Set;
 
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from a source Map to a target Map type.
@@ -38,8 +39,8 @@ final class MapToMapConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Map.class, Map.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Map.class, Map.class));
 	}
 
 	@SuppressWarnings("unchecked")

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

@@ -16,15 +16,16 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.getMapEntryTypes;
-
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.util.Collections;
 import java.util.Map;
 import java.util.Properties;
+import java.util.Set;
 
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 
 /**
  * Converts from a Map to a single Object.
@@ -40,8 +41,8 @@ final class MapToObjectConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Map.class, Object.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Map.class, Object.class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -16,13 +16,14 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.invokeConverter;
-
 import java.lang.reflect.Array;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 import org.springframework.util.StringUtils;
 
 /**
@@ -39,8 +40,8 @@ final class ObjectToArrayConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Object.class, Object[].class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object.class, Object[].class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

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

@@ -16,14 +16,15 @@
 
 package org.springframework.core.convert.support;
 
-import static org.springframework.core.convert.support.ConversionUtils.invokeConverter;
-
 import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
+import static org.springframework.core.convert.support.ConversionUtils.*;
 import org.springframework.util.StringUtils;
 
 /**
@@ -40,8 +41,8 @@ final class ObjectToCollectionConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Object.class, Collection.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object.class, Collection.class));
 	}
 
 	@SuppressWarnings("unchecked")

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

@@ -17,8 +17,10 @@
 package org.springframework.core.convert.support;
 
 import java.io.ByteArrayInputStream;
+import java.util.Collections;
 import java.util.Map;
 import java.util.Properties;
+import java.util.Set;
 
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.TypeDescriptor;
@@ -38,8 +40,8 @@ final class ObjectToMapConverter implements GenericConverter {
 		this.conversionService = conversionService;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Object.class, Map.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object.class, Map.class));
 	}
 
 	@SuppressWarnings("unchecked")

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

@@ -19,6 +19,8 @@ package org.springframework.core.convert.support;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Collections;
+import java.util.Set;
 
 import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.TypeDescriptor;
@@ -27,9 +29,12 @@ import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 
 /**
- * Generic Converter that attempts to convert a source Object to a targetType by delegating to methods on the targetType.
- * Calls the static valueOf(sourceType) method on the targetType to perform the conversion, if such a method exists.
- * Else calls the targetType's Constructor that accepts a single sourceType argument, if such a Constructor exists.
+ * Generic Converter that attempts to convert a source Object to a target type
+ * by delegating to methods on the target type.
+ *
+ * <p>Calls the static <code>valueOf(sourceType)</code> method on the target type
+ * to perform the conversion, if such a method exists. Else calls the target type's
+ * Constructor that accepts a single sourceType argument, if such a Constructor exists.
  * Else throws a ConversionFailedException.
  *
  * @author Keith Donald
@@ -40,11 +45,12 @@ final class ObjectToObjectGenericConverter implements ConditionalGenericConverte
 	public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
 		Class<?> sourceClass = sourceType.getObjectType();
 		Class<?> targetClass = targetType.getObjectType();		
-		return getValueOfMethodOn(targetClass, sourceClass) != null || getConstructor(targetClass, sourceClass) != null;
+		return getValueOfMethodOn(targetClass, sourceClass) != null ||
+				getConstructor(targetClass, sourceClass) != null;
 	}
 
-	public Class<?>[][] getConvertibleTypes() {
-		return new Class<?>[][] { { Object.class, Object.class } };
+	public Set<ConvertiblePair> getConvertibleTypes() {
+		return Collections.singleton(new ConvertiblePair(Object.class, Object.class));
 	}
 
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
@@ -57,23 +63,29 @@ final class ObjectToObjectGenericConverter implements ConditionalGenericConverte
 		Method method = getValueOfMethodOn(targetClass, sourceClass);
 		if (method != null) {
 			target = ReflectionUtils.invokeMethod(method, null, source);
-		} else {
+		}
+		else {
 			Constructor<?> constructor = getConstructor(targetClass, sourceClass);
 			if (constructor != null) {
 				try {
 					target = constructor.newInstance(source);
-				} catch (IllegalArgumentException e) {
-					throw new ConversionFailedException(sourceType, targetType, source, e);
-				} catch (InstantiationException e) {
-					throw new ConversionFailedException(sourceType, targetType, source, e);
-				} catch (IllegalAccessException e) {
-					throw new ConversionFailedException(sourceType, targetType, source, e);
-				} catch (InvocationTargetException e) {
-					throw new ConversionFailedException(sourceType, targetType, source, e);
 				}
-			} else {
-				throw new IllegalStateException("No static valueOf(" + sourceClass.getName()
-						+ ") method or Constructor(" + sourceClass.getName() + ") exists on " + targetClass.getName());
+				catch (IllegalArgumentException ex) {
+					throw new ConversionFailedException(sourceType, targetType, source, ex);
+				}
+				catch (InstantiationException ex) {
+					throw new ConversionFailedException(sourceType, targetType, source, ex);
+				}
+				catch (IllegalAccessException ex) {
+					throw new ConversionFailedException(sourceType, targetType, source, ex);
+				}
+				catch (InvocationTargetException ex) {
+					throw new ConversionFailedException(sourceType, targetType, source, ex);
+				}
+			}
+			else {
+				throw new IllegalStateException("No static valueOf(" + sourceClass.getName() +
+						") method or Constructor(" + sourceClass.getName() + ") exists on " + targetClass.getName());
 			}
 		}
 		return target;
@@ -87,4 +99,4 @@ final class ObjectToObjectGenericConverter implements ConditionalGenericConverte
 		return ClassUtils.getConstructorIfAvailable(targetClass, sourceClass);
 	}
 
-}
+}