org.unitils.util.CollectionUtils Maven / Gradle / Ivy
/*
* Copyright 2008, Unitils.org
*
* 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.unitils.util;
import org.apache.commons.lang.ArrayUtils;
import java.util.*;
import static java.util.Arrays.asList;
/**
* Class containing collection related utilities
*
* @author Filip Neven
* @author Tim Ducheyne
*/
public class CollectionUtils {
/**
* Gets a list containing all elements from the given index to the given index.
*
* @param list The original list
* @param fromIndex The from index
* @param toIndex The to index
* @return The sub-list, not null
*/
public static List subList(List list, int fromIndex, int toIndex) {
List result = new ArrayList();
if (list == null) {
return result;
}
for (int i = fromIndex; i < toIndex; i++) {
result.add(list.get(i));
}
return result;
}
/**
* Converts the given array of elements to a set.
*
* @param elements The elements
* @return The elements as a set, empty if elements was null
*/
public static Set asSet(T... elements) {
Set result = new HashSet();
if (elements == null) {
return result;
}
result.addAll(asList(elements));
return result;
}
/**
* Converts the given array or collection object (possibly primitive array) to type Collection
*
* @param object The array or collection
* @return The object collection
*/
public static Collection convertToCollection(Object object) {
if (object instanceof Collection) {
return (Collection) object;
}
// If needed convert primitive array to object array
Object[] objectArray = convertToObjectArray(object);
// Convert array to collection
return asList(objectArray);
}
/**
* Converts the given array object (possibly primitive array) to type Object[]
*
* @param object The array
* @return The object array
*/
public static Object[] convertToObjectArray(Object object) {
if (object instanceof byte[]) {
return ArrayUtils.toObject((byte[]) object);
} else if (object instanceof short[]) {
return ArrayUtils.toObject((short[]) object);
} else if (object instanceof int[]) {
return ArrayUtils.toObject((int[]) object);
} else if (object instanceof long[]) {
return ArrayUtils.toObject((long[]) object);
} else if (object instanceof char[]) {
return ArrayUtils.toObject((char[]) object);
} else if (object instanceof float[]) {
return ArrayUtils.toObject((float[]) object);
} else if (object instanceof double[]) {
return ArrayUtils.toObject((double[]) object);
} else if (object instanceof boolean[]) {
return ArrayUtils.toObject((boolean[]) object);
} else {
return (Object[]) object;
}
}
}