/*
* Copyright 2014 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.data.convert;
import java.util.Collection;
import java.util.EnumMap;
import java.util.EnumSet;
import java.util.Map;
import org.springframework.util.Assert;
/**
* Wrapper around Spring's {@link org.springframework.core.CollectionFactory} to add support for additional, sepcial
* collection types.
*
* @author Oliver Gierke
*/
public class CollectionFactory {
private CollectionFactory() {}
/**
* Creates a new collection instance for the given collection type. Might also inspect the element type in case
* special collections are requested (e.g. {@link EnumSet}).
*
* @param collectionType must not be {@literal null}.
* @param elementType can be {@literal null}.
* @param size the initial size of the collection to be created.
* @return
*/
@SuppressWarnings("unchecked")
public static Collection<Object> createCollection(Class<?> collectionType, Class<?> elementType, int size) {
Assert.notNull(collectionType, "Collection type must not be null!");
if (EnumSet.class.equals(collectionType)) {
return EnumSet.noneOf(asEnumType(elementType));
}
return org.springframework.core.CollectionFactory.createCollection(collectionType, size);
}
/**
* Creates a new map instance for the given map type. Might also inspect the key type in case special maps are
* requested (e.g. {@link EnumMap}).
*
* @param mapType must not be {@literal null}.
* @param keyType can be {@literal null}.
* @param size the initial size of the collection to be created.
* @return
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static Map<Object, Object> createMap(Class<?> mapType, Class<?> keyType, int size) {
Assert.notNull(mapType, "Map type must not be null!");
if (EnumMap.class.isAssignableFrom(mapType)) {
return new EnumMap(asEnumType(keyType));
}
return org.springframework.core.CollectionFactory.createMap(mapType, size);
}
/**
* Returns the given type as subtype of {@link Enum}.
*
* @param enumType must not be {@literal null}.
* @return
* @throws IllegalArgumentException in case the given type is not a subtype of {@link Enum}.
*/
@SuppressWarnings("rawtypes")
private static Class<? extends Enum> asEnumType(Class<?> enumType) {
Assert.notNull(enumType, "EnumType must not be null!");
if (!Enum.class.isAssignableFrom(enumType)) {
throw new IllegalArgumentException(String.format("Given type %s is not an enum type!", enumType.getName()));
}
return enumType.asSubclass(Enum.class);
}
}