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Change GenericConversionService to match interfaces before enums #607

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67 changes: 38 additions & 29 deletions ...core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -17,9 +17,10 @@
package org.springframework.core.convert.support;

import java.lang.reflect.Array;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Deque;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
Expand Down Expand Up @@ -518,8 +519,8 @@ public void remove(Class<?> sourceType, Class<?> targetType) {
*/
public GenericConverter find(TypeDescriptor sourceType, TypeDescriptor targetType) {
// Search the full type hierarchy
List<Class<?>> sourceCandidates = getClassHierarchy(sourceType.getType());
List<Class<?>> targetCandidates = getClassHierarchy(targetType.getType());
Iterable<Class<?>> sourceCandidates = getClassHierarchy(sourceType.getType());
Iterable<Class<?>> targetCandidates = getClassHierarchy(targetType.getType());
for (Class<?> sourceCandidate : sourceCandidates) {
for (Class<?> targetCandidate : targetCandidates) {
ConvertiblePair convertiblePair = new ConvertiblePair(sourceCandidate, targetCandidate);
Expand Down Expand Up @@ -555,41 +556,49 @@ private GenericConverter getRegisteredConverter(TypeDescriptor sourceType,
/**
* Returns an ordered class hierarchy for the given type.
* @param type the type
* @return an ordered list of all classes that the given type extends or implements
* @return an Iterable of all classes that the given type extends or implements
*/
private List<Class<?>> getClassHierarchy(Class<?> type) {
List<Class<?>> hierarchy = new ArrayList<Class<?>>(20);
Set<Class<?>> visited = new HashSet<Class<?>>(20);
addToClassHierarchy(0, ClassUtils.resolvePrimitiveIfNecessary(type), false, hierarchy, visited);
private Iterable<Class<?>> getClassHierarchy(Class<?> type) {
Deque<Class<?>> classStack = new ArrayDeque<Class<?>>(20);
LinkedHashSet<Class<?>> hierarchy = new LinkedHashSet<Class<?>>(20);
boolean array = type.isArray();
int i = 0;
while (i < hierarchy.size()) {
Class<?> candidate = hierarchy.get(i);
candidate = (array ? candidate.getComponentType() : ClassUtils.resolvePrimitiveIfNecessary(candidate));

classStack.push(ClassUtils.resolvePrimitiveIfNecessary(type));

Class<?> candidate = null;
while((candidate = classStack.pollFirst()) != null) {
candidate = ClassUtils.resolvePrimitiveIfNecessary(candidate);
hierarchy.add(!candidate.isArray() && array ? Array.newInstance(candidate, 0).getClass() : candidate);

Class<?> superclass = candidate.getSuperclass();
if (candidate.getSuperclass() != null && superclass != Object.class) {
addToClassHierarchy(i + 1, candidate.getSuperclass(), array, hierarchy, visited);
if (superclass != null && superclass != Object.class && superclass != Enum.class) {
classStack.push(superclass);
}
for (Class<?> implementedInterface : candidate.getInterfaces()) {
addToClassHierarchy(hierarchy.size(), implementedInterface, array, hierarchy, visited);

for(Class<?> implementedInterface : candidate.getInterfaces()) {
// add interfaces to the other end of the queue, so that
// concrete classes always come first in the hierarchy
classStack.addLast(implementedInterface);
}
i++;
}
addToClassHierarchy(hierarchy.size(), Object.class, array, hierarchy, visited);
addToClassHierarchy(hierarchy.size(), Object.class, false, hierarchy, visited);
return hierarchy;
}

private void addToClassHierarchy(int index, Class<?> type, boolean asArray,
List<Class<?>> hierarchy, Set<Class<?>> visited) {
if (asArray) {
type = Array.newInstance(type, 0).getClass();

// make sure Enum comes at the "end" of the hierarchy (if necessary)
if(type.isEnum()) {
if(array) {
hierarchy.add(Array.newInstance(Enum.class, 0).getClass());
}
hierarchy.add(Enum.class);
}
if (visited.add(type)) {
hierarchy.add(index, type);

// always add Object to hierarchy
if(array) {
hierarchy.add(Array.newInstance(Object.class, 0).getClass());
}
hierarchy.add(Object.class);

return hierarchy;
}

@Override
public String toString() {
StringBuilder builder = new StringBuilder();
Expand Down
101 changes: 92 additions & 9 deletions ...src/test/java/org/springframework/core/convert/support/GenericConversionServiceTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -758,6 +758,21 @@ public void testEnumWithInterfaceToStringConversion() {
assertEquals("1", result);
}

@Test
public void testStringToEnumWithInterfaceConversion() {
conversionService.addConverterFactory(new StringToEnumConverterFactory());
conversionService.addConverterFactory(new StringToMyEnumInterfaceConverterFactory());
assertEquals(MyEnum.A, conversionService.convert("1", MyEnum.class));
}

@Test
public void testStringToEnumWithBaseInterfaceConversion() {
conversionService.addConverterFactory(new StringToEnumConverterFactory());
conversionService.addConverterFactory(new StringToMyEnumBaseInterfaceConverterFactory());
assertEquals(MyEnum.A, conversionService.convert("base1", MyEnum.class));
}


@Test
public void convertNullAnnotatedStringToString() throws Exception {
DefaultConversionService.addDefaultConverters(conversionService);
Expand Down Expand Up @@ -930,20 +945,35 @@ public int getNestedMatchAttempts() {
}
}


interface MyEnumInterface {

interface MyEnumBaseInterface {
String getBaseCode();
}

interface MyEnumInterface extends MyEnumBaseInterface {
String getCode();
}

public static enum MyEnum implements MyEnumInterface {

A {
@Override
public String getCode() {
return "1";
}
}
A("1"),
B("2"),
C("3");

private String code;

MyEnum(String code) {
this.code = code;
}

@Override
public String getCode() {
return code;
}

@Override
public String getBaseCode() {
return "base" + code;
}
}


Expand All @@ -970,6 +1000,59 @@ public String convert(T source) {
return source.getCode();
}
}

private static class StringToMyEnumInterfaceConverterFactory implements ConverterFactory<String, MyEnumInterface> {

@SuppressWarnings("unchecked")
public <T extends MyEnumInterface> Converter<String, T> getConverter(Class<T> targetType) {
return new StringToMyEnumInterfaceConverter(targetType);
}

private static class StringToMyEnumInterfaceConverter<T extends Enum<?> & MyEnumInterface> implements Converter<String, T> {
private final Class<T> enumType;

public StringToMyEnumInterfaceConverter(Class<T> enumType) {
this.enumType = enumType;
}

public T convert(String source) {
for (T value : enumType.getEnumConstants()) {
if (value.getCode().equals(source)) {
return value;
}
}
return null;
}
}

}

private static class StringToMyEnumBaseInterfaceConverterFactory implements ConverterFactory<String, MyEnumBaseInterface> {

@SuppressWarnings("unchecked")
public <T extends MyEnumBaseInterface> Converter<String, T> getConverter(Class<T> targetType) {
return new StringToMyEnumBaseInterfaceConverter(targetType);
}

private static class StringToMyEnumBaseInterfaceConverter<T extends Enum<?> & MyEnumBaseInterface> implements Converter<String, T> {
private final Class<T> enumType;

public StringToMyEnumBaseInterfaceConverter(Class<T> enumType) {
this.enumType = enumType;
}

public T convert(String source) {
for (T value : enumType.getEnumConstants()) {
if (value.getBaseCode().equals(source)) {
return value;
}
}
return null;
}
}

}


public static class MyStringToStringCollectionConverter implements Converter<String, Collection<String>> {

Expand Down