package org.springframework.boot.convert;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Set;
import java.util.stream.Stream;
import org.springframework.core.CollectionFactory;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.core.convert.converter.ConditionalGenericConverter;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
final class DelimitedStringToCollectionConverter implements ConditionalGenericConverter {
private final ConversionService conversionService;
DelimitedStringToCollectionConverter(ConversionService conversionService) {
Assert.notNull(conversionService, "ConversionService must not be null");
this.conversionService = conversionService;
}
@Override
public Set<ConvertiblePair> getConvertibleTypes() {
return Collections.singleton(new ConvertiblePair(String.class, Collection.class));
}
@Override
public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
return targetType.getElementTypeDescriptor() == null
|| this.conversionService.canConvert(sourceType, targetType.getElementTypeDescriptor());
}
@Override
public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
if (source == null) {
return null;
}
return convert((String) source, sourceType, targetType);
}
private Object convert(String source, TypeDescriptor sourceType, TypeDescriptor targetType) {
Delimiter delimiter = targetType.getAnnotation(Delimiter.class);
String[] elements = getElements(source, (delimiter != null) ? delimiter.value() : ",");
TypeDescriptor elementDescriptor = targetType.getElementTypeDescriptor();
Collection<Object> target = createCollection(targetType, elementDescriptor, elements.length);
Stream<Object> stream = Arrays.stream(elements).map(String::trim);
if (elementDescriptor != null) {
stream = stream.map((element) -> this.conversionService.convert(element, sourceType, elementDescriptor));
}
stream.forEach(target::add);
return target;
}
private Collection<Object> createCollection(TypeDescriptor targetType, TypeDescriptor elementDescriptor,
int length) {
return CollectionFactory.createCollection(targetType.getType(),
(elementDescriptor != null) ? elementDescriptor.getType() : null, length);
}
private String[] getElements(String source, String delimiter) {
return StringUtils.delimitedListToStringArray(source, Delimiter.NONE.equals(delimiter) ? null : delimiter);
}
}