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smarter guessing of the element type (SPR-7283)

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This commit is contained in:
Juergen Hoeller
2010-06-14 22:58:18 +00:00
parent 379bc5a8a6
commit 902938e95f
4 changed files with 204 additions and 111 deletions
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89
org.springframework.core/src/main/java/org/springframework/core/convert/TypeDescriptor.java
View File

@@ -26,6 +26,7 @@ import org.springframework.core.GenericCollectionTypeResolver;
import org.springframework.core.MethodParameter;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;
/**
@@ -34,7 +35,7 @@ import org.springframework.util.ObjectUtils;
* @author Keith Donald
* @author Andy Clement
* @author Juergen Hoeller
* @since 3.0
* @since 3.0
*/
public class TypeDescriptor {
@@ -44,7 +45,7 @@ public class TypeDescriptor {
private static final Map<Class<?>, TypeDescriptor> typeDescriptorCache = new HashMap<Class<?>, TypeDescriptor>();
private static final Annotation[] EMPTY_ANNOTATION_ARRAY = new Annotation[0];
static {
typeDescriptorCache.put(boolean.class, new TypeDescriptor(boolean.class));
typeDescriptorCache.put(Boolean.class, new TypeDescriptor(Boolean.class));
@@ -75,13 +76,13 @@ public class TypeDescriptor {
private Object value;
private TypeDescriptor elementType;
private TypeDescriptor mapKeyType;
private TypeDescriptor mapValueType;
private Annotation[] annotations;
/**
* Create a new type descriptor from a method or constructor parameter.
@@ -248,15 +249,15 @@ public class TypeDescriptor {
* Return the element type as a type descriptor.
*/
public synchronized TypeDescriptor getElementTypeDescriptor() {
if (elementType == null) {
elementType = forElementType(resolveElementType());
if (this.elementType == null) {
this.elementType = forElementType(resolveElementType());
}
return elementType;
return this.elementType;
}
/**
* Return the element type as a type descriptor; if the element type is null (cannot be determined),
* the type descriptor is derived from the element argument.
* Return the element type as a type descriptor. If the element type is null
* (cannot be determined), the type descriptor is derived from the element argument.
* @param element the element
* @return the element type descriptor
*/
@@ -273,7 +274,7 @@ public class TypeDescriptor {
}
/**
* Is this descriptor for a map where the key type and value type are known?
* Is this descriptor for a map where the key type and value type are known?
*/
public boolean isMapEntryTypeKnown() {
return (isMap() && getMapKeyType() != null && getMapValueType() != null);
@@ -291,14 +292,15 @@ public class TypeDescriptor {
* Returns map key type as a type descriptor.
*/
public synchronized TypeDescriptor getMapKeyTypeDescriptor() {
if (mapKeyType == null) {
mapKeyType = forElementType(resolveMapKeyType());
if (this.mapKeyType == null) {
this.mapKeyType = forElementType(resolveMapKeyType());
}
return mapKeyType;
return this.mapKeyType;
}
/**
* Return the map key type as a type descriptor; if the key type is null (cannot be determined), the type descriptor is derived from the key argument.
* Return the map key type as a type descriptor. If the key type is null
* (cannot be determined), the type descriptor is derived from the key argument.
* @param key the key
* @return the map key type descriptor
*/
@@ -306,7 +308,7 @@ public class TypeDescriptor {
TypeDescriptor keyType = getMapKeyTypeDescriptor();
return keyType != TypeDescriptor.NULL ? keyType : TypeDescriptor.forObject(key);
}
/**
* Determine the generic value type of the wrapped Map parameter/field, if any.
* @return the generic type, or <code>null</code> if none
@@ -314,19 +316,19 @@ public class TypeDescriptor {
public Class<?> getMapValueType() {
return getMapValueTypeDescriptor().getType();
}
/**
* Returns map value type as a type descriptor.
*/
public synchronized TypeDescriptor getMapValueTypeDescriptor() {
if (this.mapValueType == null) {
mapValueType = forElementType(resolveMapValueType());
this.mapValueType = forElementType(resolveMapValueType());
}
return this.mapValueType;
}
/**
* Return the map value type as a type descriptor; if the value type is null
* Return the map value type as a type descriptor. If the value type is null
* (cannot be determined), the type descriptor is derived from the value argument.
* @param value the value
* @return the map value type descriptor
@@ -355,7 +357,7 @@ public class TypeDescriptor {
return annotation;
}
}
return null;
return null;
}
/**
@@ -423,14 +425,14 @@ public class TypeDescriptor {
ObjectUtils.nullSafeEquals(getMapValueType(), td.getMapValueType());
}
else {
return annotatedTypeEquals;
return annotatedTypeEquals;
}
}
public int hashCode() {
return getType().hashCode();
}
/**
* A textual representation of the type descriptor (eg. Map<String,Foo>) for use in messages
*/
@@ -459,7 +461,7 @@ public class TypeDescriptor {
}
else if (isCollection()) {
Class<?> elementType = getElementType();
builder.append("<").append(elementType != null ? ClassUtils.getQualifiedName(elementType) : "?").append(">");
builder.append("<").append(elementType != null ? ClassUtils.getQualifiedName(elementType) : "?").append(">");
}
builder.append("]");
return builder.toString();
@@ -468,7 +470,7 @@ public class TypeDescriptor {
// internal helpers
private Class<?> resolveElementType() {
if (isArray()) {
return getType().getComponentType();
@@ -478,9 +480,9 @@ public class TypeDescriptor {
}
else {
return null;
}
}
}
@SuppressWarnings("unchecked")
private Class<?> resolveCollectionElementType() {
if (this.field != null) {
@@ -490,17 +492,14 @@ public class TypeDescriptor {
return GenericCollectionTypeResolver.getCollectionParameterType(this.methodParameter);
}
else if (this.value instanceof Collection) {
Collection coll = (Collection) this.value;
if (!coll.isEmpty()) {
Object elem = coll.iterator().next();
if (elem != null) {
return elem.getClass();
}
Class<?> elementType = CollectionUtils.findCommonElementType((Collection) this.value);
if (elementType != null) {
return elementType;
}
}
return (this.type != null ? GenericCollectionTypeResolver.getCollectionType((Class<? extends Collection>) this.type) : null);
return (this.type != null ? GenericCollectionTypeResolver.getCollectionType((Class<? extends Collection>) this.type) : null);
}
@SuppressWarnings("unchecked")
private Class<?> resolveMapKeyType() {
if (this.field != null) {
@@ -510,12 +509,9 @@ public class TypeDescriptor {
return GenericCollectionTypeResolver.getMapKeyParameterType(this.methodParameter);
}
else if (this.value instanceof Map<?, ?>) {
Map<?, ?> map = (Map<?, ?>) this.value;
if (!map.isEmpty()) {
Object key = map.keySet().iterator().next();
if (key != null) {
return key.getClass();
}
Class<?> keyType = CollectionUtils.findCommonElementType(((Map<?, ?>) this.value).keySet());
if (keyType != null) {
return keyType;
}
}
return (this.type != null && isMap() ? GenericCollectionTypeResolver.getMapKeyType((Class<? extends Map>) this.type) : null);
@@ -530,17 +526,14 @@ public class TypeDescriptor {
return GenericCollectionTypeResolver.getMapValueParameterType(this.methodParameter);
}
else if (this.value instanceof Map<?, ?>) {
Map<?, ?> map = (Map<?, ?>) this.value;
if (!map.isEmpty()) {
Object val = map.values().iterator().next();
if (val != null) {
return val.getClass();
}
Class<?> valueType = CollectionUtils.findCommonElementType(((Map<?, ?>) this.value).values());
if (valueType != null) {
return valueType;
}
}
return (isMap() && this.type != null ? GenericCollectionTypeResolver.getMapValueType((Class<? extends Map>) this.type) : null);
}
private Annotation[] resolveAnnotations() {
if (this.field != null) {
return this.field.getAnnotations();

114
org.springframework.core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java
View File

@@ -31,7 +31,6 @@ import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.GenericTypeResolver;
import org.springframework.core.convert.ConversionException;
import org.springframework.core.convert.ConversionFailedException;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.ConverterNotFoundException;
@@ -55,8 +54,6 @@ import org.springframework.util.ClassUtils;
*/
public class GenericConversionService implements ConversionService, ConverterRegistry {
private static final Log logger = LogFactory.getLog(GenericConversionService.class);
private static final GenericConverter NO_OP_CONVERTER = new GenericConverter() {
public Set<ConvertiblePair> getConvertibleTypes() {
return null;
@@ -81,11 +78,16 @@ public class GenericConversionService implements ConversionService, ConverterReg
}
};
private static final Log logger = LogFactory.getLog(GenericConversionService.class);
private final Map<Class<?>, Map<Class<?>, MatchableConverters>> converters =
new HashMap<Class<?>, Map<Class<?>, MatchableConverters>>(36);
private final Map<ConverterCacheKey, GenericConverter> converterCache = new ConcurrentHashMap<ConverterCacheKey, GenericConverter>();
private final Map<ConverterCacheKey, GenericConverter> converterCache =
new ConcurrentHashMap<ConverterCacheKey, GenericConverter>();
// implementing ConverterRegistry
public void addConverter(Converter<?, ?> converter) {
@@ -119,6 +121,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
invalidateCache();
}
// implementing ConversionService
public boolean canConvert(Class<?> sourceType, Class<?> targetType) {
@@ -132,26 +135,20 @@ public class GenericConversionService implements ConversionService, ConverterReg
public boolean canConvert(TypeDescriptor sourceType, TypeDescriptor targetType) {
assertNotNull(sourceType, targetType);
if (logger.isDebugEnabled()) {
logger.debug("Checking if I can convert " + sourceType + " to " + targetType);
if (logger.isTraceEnabled()) {
logger.trace("Checking if I can convert " + sourceType + " to " + targetType);
}
if (sourceType == TypeDescriptor.NULL || targetType == TypeDescriptor.NULL) {
if (logger.isDebugEnabled()) {
logger.debug("Yes, I can convert");
}
logger.trace("Yes, I can convert");
return true;
}
GenericConverter converter = getConverter(sourceType, targetType);
if (converter != null) {
if (logger.isDebugEnabled()) {
logger.debug("Yes, I can convert");
}
logger.trace("Yes, I can convert");
return true;
}
else {
if (logger.isDebugEnabled()) {
logger.debug("No, I cannot convert");
}
logger.trace("No, I cannot convert");
return false;
}
}
@@ -170,31 +167,18 @@ public class GenericConversionService implements ConversionService, ConverterReg
return result;
}
if (targetType == TypeDescriptor.NULL) {
if (logger.isDebugEnabled()) {
logger.debug("Converted to null");
}
logger.debug("Converted to null");
return null;
}
GenericConverter converter = getConverter(sourceType, targetType);
if (converter == null) {
ConverterNotFoundException e = new ConverterNotFoundException(sourceType, targetType);
if (logger.isDebugEnabled()) {
logger.debug(e);
}
throw e;
throw new ConverterNotFoundException(sourceType, targetType);
}
try {
Object result = ConversionUtils.invokeConverter(converter, source, sourceType, targetType);
if (logger.isDebugEnabled()) {
logger.debug("Converted to " + StylerUtils.style(result));
}
return result;
} catch (ConversionException e) {
if (logger.isDebugEnabled()) {
logger.debug(e);
}
throw e;
Object result = ConversionUtils.invokeConverter(converter, source, sourceType, targetType);
if (logger.isDebugEnabled()) {
logger.debug("Converted to " + StylerUtils.style(result));
}
return result;
}
public String toString() {
@@ -215,12 +199,14 @@ public class GenericConversionService implements ConversionService, ConverterReg
return builder.toString();
}
// subclassing hooks
/**
* 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.
* Template method to convert a null source.
* <p>Default implementation returns <code>null</code>.
* Throws a {@link ConversionFailedException} if the targetType is a primitive type,
* as <code>null</code> 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
@@ -247,10 +233,10 @@ public class GenericConversionService implements ConversionService, ConverterReg
*/
protected GenericConverter getConverter(TypeDescriptor sourceType, TypeDescriptor targetType) {
ConverterCacheKey key = new ConverterCacheKey(sourceType, targetType);
GenericConverter converter = converterCache.get(key);
GenericConverter converter = this.converterCache.get(key);
if (converter != null) {
if (logger.isDebugEnabled()) {
logger.debug("Matched cached converter " + converter);
if (logger.isTraceEnabled()) {
logger.trace("Matched cached converter " + converter);
}
return converter != NO_MATCH ? converter : null;
}
@@ -260,7 +246,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
if (logger.isTraceEnabled()) {
logger.trace("Caching under " + key);
}
converterCache.put(key, converter);
this.converterCache.put(key, converter);
return converter;
}
converter = getDefaultConverter(sourceType, targetType);
@@ -268,13 +254,13 @@ public class GenericConversionService implements ConversionService, ConverterReg
if (logger.isTraceEnabled()) {
logger.trace("Caching under " + key);
}
converterCache.put(key, converter);
this.converterCache.put(key, converter);
return converter;
}
if (logger.isTraceEnabled()) {
logger.trace("Caching NO_MATCH under " + key);
}
converterCache.put(key, NO_MATCH);
this.converterCache.put(key, NO_MATCH);
return null;
}
}
@@ -290,9 +276,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
*/
protected GenericConverter getDefaultConverter(TypeDescriptor sourceType, TypeDescriptor targetType) {
if (sourceType.isAssignableTo(targetType)) {
if (logger.isDebugEnabled()) {
logger.debug("Matched default NO_OP_CONVERTER");
}
logger.trace("Matched default NO_OP_CONVERTER");
return NO_OP_CONVERTER;
}
else {
@@ -471,7 +455,9 @@ public class GenericConversionService implements ConversionService, ConverterReg
}
}
private GenericConverter matchConverter(MatchableConverters matchable, TypeDescriptor sourceFieldType, TypeDescriptor targetFieldType) {
private GenericConverter matchConverter(
MatchableConverters matchable, TypeDescriptor sourceFieldType, TypeDescriptor targetFieldType) {
if (matchable == null) {
return null;
}
@@ -566,20 +552,20 @@ public class GenericConversionService implements ConversionService, ConverterReg
logger.trace("Matching " + conditional);
}
if (conditional.matches(sourceType, targetType)) {
if (logger.isDebugEnabled()) {
logger.debug("Matched converter " + conditional);
if (logger.isTraceEnabled()) {
logger.trace("Matched converter " + conditional);
}
return conditional;
}
else {
if (logger.isDebugEnabled()) {
logger.debug("Did not match converter " + conditional);
if (logger.isTraceEnabled()) {
logger.trace("Did not match converter " + conditional);
}
}
}
}
if (this.defaultConverter != null && logger.isDebugEnabled()) {
logger.debug("Matched converter " + this.defaultConverter);
if (this.defaultConverter != null && logger.isTraceEnabled()) {
logger.trace("Matched converter " + this.defaultConverter);
}
return this.defaultConverter;
}
@@ -587,7 +573,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
public String toString() {
if (this.conditionalConverters != null) {
StringBuilder builder = new StringBuilder();
for (Iterator<ConditionalGenericConverter> it = this.conditionalConverters.iterator(); it.hasNext(); ) {
for (Iterator<ConditionalGenericConverter> it = this.conditionalConverters.iterator(); it.hasNext();) {
builder.append(it.next());
if (it.hasNext()) {
builder.append(", ");
@@ -603,7 +589,8 @@ public class GenericConversionService implements ConversionService, ConverterReg
}
}
}
private static final class ConverterCacheKey {
private final TypeDescriptor sourceType;
@@ -615,20 +602,23 @@ public class GenericConversionService implements ConversionService, ConverterReg
this.targetType = targetType;
}
public boolean equals(Object o) {
if (!(o instanceof ConverterCacheKey)) {
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof ConverterCacheKey)) {
return false;
}
ConverterCacheKey key = (ConverterCacheKey) o;
return sourceType.equals(key.sourceType) && targetType.equals(key.targetType);
ConverterCacheKey otherKey = (ConverterCacheKey) other;
return this.sourceType.equals(otherKey.sourceType) && this.targetType.equals(otherKey.targetType);
}
public int hashCode() {
return sourceType.hashCode() * 29 + targetType.hashCode();
return this.sourceType.hashCode() * 29 + this.targetType.hashCode();
}
public String toString() {
return "[ConverterCacheKey sourceType = " + sourceType + ", targetType = " + targetType + "]";
return "ConverterCacheKey [sourceType = " + this.sourceType + ", targetType = " + this.targetType + "]";
}
}

26
org.springframework.core/src/main/java/org/springframework/util/CollectionUtils.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2009 the original author or authors.
* Copyright 2002-2010 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.
@@ -276,6 +276,30 @@ public abstract class CollectionUtils {
return true;
}
/**
* Find the common element type of the given Collection, if any.
* @param collection the Collection to check
* @return the common element type, or <code>null</code> if no clear
* common type has been found (or the collection was empty)
*/
public static Class<?> findCommonElementType(Collection collection) {
if (isEmpty(collection)) {
return null;
}
Class<?> candidate = null;
for (Object val : collection) {
if (val != null) {
if (candidate == null) {
candidate = val.getClass();
}
else if (candidate != val.getClass()) {
return null;
}
}
}
return candidate;
}
/**
* Adapts an enumeration to an iterator.
* @param enumeration the enumeration