spring CollectionToObjectConverter 源码
spring CollectionToObjectConverter 代码
文件路径：/spring-core/src/main/java/org/springframework/core/convert/support/CollectionToObjectConverter.java
/*
* Copyright 2002-2017 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.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.core.convert.support;
import java.util.Collection;
import java.util.Collections;
import java.util.Set;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.core.convert.converter.ConditionalGenericConverter;
import org.springframework.lang.Nullable;
/**
* Converts a Collection to an Object by returning the first collection element after converting it to the desired targetType.
*
* @author Keith Donald
* @since 3.0
*/
final class CollectionToObjectConverter implements ConditionalGenericConverter {
private final ConversionService conversionService;
public CollectionToObjectConverter(ConversionService conversionService) {
this.conversionService = conversionService;
}
@Override
public Set<ConvertiblePair> getConvertibleTypes() {
return Collections.singleton(new ConvertiblePair(Collection.class, Object.class));
}
@Override
public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
return ConversionUtils.canConvertElements(sourceType.getElementTypeDescriptor(), targetType, this.conversionService);
}
@Override
@Nullable
public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
if (source == null) {
return null;
}
if (sourceType.isAssignableTo(targetType)) {
return source;
}
Collection<?> sourceCollection = (Collection<?>) source;
if (sourceCollection.isEmpty()) {
return null;
}
Object firstElement = sourceCollection.iterator().next();
return this.conversionService.convert(firstElement, sourceType.elementTypeDescriptor(firstElement), targetType);
}
}
相关信息
相关文章
spring AbstractConditionalEnumConverter 源码
spring ArrayToArrayConverter 源码
spring ArrayToCollectionConverter 源码
spring ArrayToObjectConverter 源码
spring ArrayToStringConverter 源码
spring CharacterToNumberFactory 源码
spring CollectionToArrayConverter 源码
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
7、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦