/* Copyright 2004 The Apache Software Foundation
*
* 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.
*/
import java.lang.reflect.Array;
/**
* <p>Operations on arrays, primitive arrays (like <code>int[]</code>) and
* primitive wrapper arrays (like <code>Integer[]</code>).</p>
*
* <p>This class tries to handle <code>null</code> input gracefully.
* An exception will not be thrown for a <code>null</code>
* array input. However, an Object array that contains a <code>null</code>
* element may throw an exception. Each method documents its behaviour.</p>
*
* @author Stephen Colebourne
* @author Moritz Petersen
* @author <a href="mailto:[email protected]">Fredrik Westermarck</a>
* @author Nikolay Metchev
* @author Matthew Hawthorne
* @author Tim O'Brien
* @author Pete Gieser
* @author Gary Gregory
* @author <a href="mailto:[email protected]">Ashwin S</a>
* @author Maarten Coene
* @since 2.0
* @version $Id: ArrayUtils.java 632503 2008-03-01 00:21:52Z ggregory $
*/
public class Main {
/**
* <p>Copies the given array and adds the given element at the end of the new array.</p>
*
* <p>The new array contains the same elements of the input
* array plus the given element in the last position. The component type of
* the new array is the same as that of the input array.</p>
*
* <p>If the input array is <code>null</code>, a new one element array is returned
* whose component type is the same as the element.</p>
*
* <pre>
* ArrayUtils.add(null, 0) = [0]
* ArrayUtils.add([1], 0) = [1, 0]
* ArrayUtils.add([1, 0], 1) = [1, 0, 1]
* </pre>
*
* @param array the array to copy and add the element to, may be <code>null</code>
* @param element the object to add at the last index of the new array
* @return A new array containing the existing elements plus the new element
* @since 2.1
*/
public static double[] add(double[] array, double element) {
double[] newArray = (double[])copyArrayGrow1(array, Double.TYPE);
newArray[newArray.length - 1] = element;
return newArray;
}
/**
* Returns a copy of the given array of size 1 greater than the argument.
* The last value of the array is left to the default value.
*
* @param array The array to copy, must not be <code>null</code>.
* @param newArrayComponentType If <code>array</code> is <code>null</code>, create a
* size 1 array of this type.
* @return A new copy of the array of size 1 greater than the input.
*/
private static Object copyArrayGrow1(Object array, Class newArrayComponentType) {
if (array != null) {
int arrayLength = Array.getLength(array);
Object newArray = Array.newInstance(array.getClass().getComponentType(), arrayLength + 1);
System.arraycopy(array, 0, newArray, 0, arrayLength);
return newArray;
}
return Array.newInstance(newArrayComponentType, 1);
}
}
|
|