net.gdface.utils.ArrayUtils Maven / Gradle / Ivy
package net.gdface.utils;
import java.lang.reflect.Array;
import java.util.Arrays;
public class ArrayUtils {
private ArrayUtils() {}
/**
* 清除array中为{@code null}的元素
* @param array 输入的数组
* @return 如果 array为{@code null}或长度为0或array中没有{@code null}元素则返回array,否则返回新的不含{@code null}的数组
*/
@SuppressWarnings("unchecked")
public static final T[] cleanNull(T[] array){
if(null == array || array.length == 0){
return array;
}
T[] copy = (T[]) Array.newInstance(array.getClass().getComponentType(), array.length);
int c = 0;
for(int i=0; i < array.length; ++i){
if(null != array[i]){
copy[c++] = array[i];
}
}
return c == array.length ? array : Arrays.copyOf(copy, c);
}
/**
* 返回第一个为{@code null}元素的索引,没找到返回-1,如果输入为{@code null}则返回-2
* @param objects
*/
public static int indexOfFirstNull(Object...objects) {
if(objects != null){
for(int i=0;i< objects.length;++i){
if(null == objects[i]){
return i;
}
}
return -1;
}
return -2;
}
/**
* @param objects
* @return true if any one of object is null or objects is null
*/
public static boolean hasNull(Object...objects) {
return indexOfFirstNull(objects) != -1;
}
/**
* Adds all the elements of the given arrays into a new array.
*
The new array contains all of the element of {@code array1} followed
* by all of the elements {@code array2}. When an array is returned, it is always
* a new array.
*
*
* ArrayUtils.addAll(null, null) = null
* ArrayUtils.addAll(array1, null) = cloned copy of array1
* ArrayUtils.addAll(null, array2) = cloned copy of array2
* ArrayUtils.addAll([], []) = []
* ArrayUtils.addAll([null], [null]) = [null, null]
* ArrayUtils.addAll(["a", "b", "c"], ["1", "2", "3"]) = ["a", "b", "c", "1", "2", "3"]
*
*
* @param the component type of the array
* @param array1 the first array whose elements are added to the new array, may be {@code null}
* @param array2 the second array whose elements are added to the new array, may be {@code null}
* @return The new array, {@code null} if both arrays are {@code null}.
* The type of the new array is the type of the first array,
* unless the first array is null, in which case the type is the same as the second array.
* @since 2.1
* @throws IllegalArgumentException if the array types are incompatible
*/
public static T[] addAll(final T[] array1, @SuppressWarnings("unchecked") final T... array2) {
if (array1 == null) {
return clone(array2);
} else if (array2 == null) {
return clone(array1);
}
final Class type1 = array1.getClass().getComponentType();
@SuppressWarnings("unchecked") // OK, because array is of type T
final T[] joinedArray = (T[]) Array.newInstance(type1, array1.length + array2.length);
System.arraycopy(array1, 0, joinedArray, 0, array1.length);
try {
System.arraycopy(array2, 0, joinedArray, array1.length, array2.length);
} catch (final ArrayStoreException ase) {
// Check if problem was due to incompatible types
/*
* We do this here, rather than before the copy because:
* - it would be a wasted check most of the time
* - safer, in case check turns out to be too strict
*/
final Class type2 = array2.getClass().getComponentType();
if (!type1.isAssignableFrom(type2)) {
throw new IllegalArgumentException("Cannot store " + type2.getName() + " in an array of "
+ type1.getName(), ase);
}
throw ase; // No, so rethrow original
}
return joinedArray;
}
// Clone
//-----------------------------------------------------------------------
/**
* Shallow clones an array returning a typecast result and handling
* {@code null}.
*
*
The objects in the array are not cloned, thus there is no special
* handling for multi-dimensional arrays.
*
*
This method returns {@code null} for a {@code null} input array.
*
* @param the component type of the array
* @param array the array to shallow clone, may be {@code null}
* @return the cloned array, {@code null} if {@code null} input
*/
public static T[] clone(final T[] array) {
if (array == null) {
return null;
}
return array.clone();
}
}