org.springframework.core.convert.support.CollectionToArrayConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2009 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
*
* http://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.lang.reflect.Array;
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;
/**
* Converts a Collection to an array.
*
* First, creates a new array of the requested targetType with a length equal to the
* size of the source Collection. Then sets each collection element into the array.
* Will perform an element conversion from the collection's parameterized type to the
* array's component type if necessary.
*
* @author Keith Donald
* @since 3.0
*/
final class CollectionToArrayConverter implements ConditionalGenericConverter {
private final ConversionService conversionService;
public CollectionToArrayConverter(ConversionService conversionService) {
this.conversionService = conversionService;
}
public Set getConvertibleTypes() {
return Collections.singleton(new ConvertiblePair(Collection.class, Object[].class));
}
public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
return this.conversionService.canConvert(sourceType.getElementTypeDescriptor(), targetType.getElementTypeDescriptor());
}
public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
if (source == null) {
return null;
}
Collection sourceCollection = (Collection) source;
Object array = Array.newInstance(targetType.getElementType(), sourceCollection.size());
int i = 0;
for (Object sourceElement : sourceCollection) {
Object targetElement = this.conversionService.convert(sourceElement, sourceType.getElementTypeDescriptor(sourceElement), targetType.getElementTypeDescriptor());
Array.set(array, i++, targetElement);
}
return array;
}
}