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/*
* Copyright 2022 The graph-support project
*
* 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.apache_gs.commons.lang3;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
/**
* Operations on arrays, primitive arrays (like {@code int[]}) and
* primitive wrapper arrays (like {@code Integer[]}).
*
* This class tries to handle {@code null} input gracefully.
* An exception will not be thrown for a {@code null}
* array input. However, an Object array that contains a {@code null}
* element may throw an exception. Each method documents its behavior.
*
*
* #ThreadSafe#
*
* @since 2.0
*/
public class ArrayUtils {
/**
* An empty immutable {@code boolean} array.
*/
public static final boolean[] EMPTY_BOOLEAN_ARRAY = {};
/**
* An empty immutable {@link Boolean} array.
*/
public static final Boolean[] EMPTY_BOOLEAN_OBJECT_ARRAY = {};
/**
* An empty immutable {@code byte} array.
*/
public static final byte[] EMPTY_BYTE_ARRAY = {};
/**
* An empty immutable {@link Byte} array.
*/
public static final Byte[] EMPTY_BYTE_OBJECT_ARRAY = {};
/**
* An empty immutable {@code char} array.
*/
public static final char[] EMPTY_CHAR_ARRAY = {};
/**
* An empty immutable {@link Character} array.
*/
public static final Character[] EMPTY_CHARACTER_OBJECT_ARRAY = {};
/**
* An empty immutable {@link Class} array.
*/
public static final Class[] EMPTY_CLASS_ARRAY = {};
/**
* An empty immutable {@code double} array.
*/
public static final double[] EMPTY_DOUBLE_ARRAY = {};
/**
* An empty immutable {@link Double} array.
*/
public static final Double[] EMPTY_DOUBLE_OBJECT_ARRAY = {};
/**
* An empty immutable {@link Field} array.
*
* @since 3.10
*/
public static final Field[] EMPTY_FIELD_ARRAY = {};
/**
* An empty immutable {@code float} array.
*/
public static final float[] EMPTY_FLOAT_ARRAY = {};
/**
* An empty immutable {@link Float} array.
*/
public static final Float[] EMPTY_FLOAT_OBJECT_ARRAY = {};
/**
* An empty immutable {@code int} array.
*/
public static final int[] EMPTY_INT_ARRAY = {};
/**
* An empty immutable {@link Integer} array.
*/
public static final Integer[] EMPTY_INTEGER_OBJECT_ARRAY = {};
/**
* An empty immutable {@code long} array.
*/
public static final long[] EMPTY_LONG_ARRAY = {};
/**
* An empty immutable {@link Long} array.
*/
public static final Long[] EMPTY_LONG_OBJECT_ARRAY = {};
/**
* An empty immutable {@link Method} array.
*
* @since 3.10
*/
public static final Method[] EMPTY_METHOD_ARRAY = {};
/**
* An empty immutable {@link Object} array.
*/
public static final Object[] EMPTY_OBJECT_ARRAY = {};
/**
* An empty immutable {@code short} array.
*/
public static final short[] EMPTY_SHORT_ARRAY = {};
/**
* An empty immutable {@link Short} array.
*/
public static final Short[] EMPTY_SHORT_OBJECT_ARRAY = {};
/**
* An empty immutable {@link String} array.
*/
public static final String[] EMPTY_STRING_ARRAY = {};
/**
* An empty immutable {@link Throwable} array.
*
* @since 3.10
*/
public static final Throwable[] EMPTY_THROWABLE_ARRAY = {};
/**
* An empty immutable {@link Type} array.
*
* @since 3.10
*/
public static final Type[] EMPTY_TYPE_ARRAY = {};
/**
* The index value when an element is not found in a list or array: {@code -1}.
* This value is returned by methods in this class and can also be used in comparisons with values returned by
* various method from {@link java.util.List}.
*/
public static final int INDEX_NOT_FOUND = -1;
/**
* Checks if an array of primitive booleans is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final boolean[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of primitive bytes is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final byte[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of primitive chars is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final char[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of primitive doubles is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final double[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of primitive floats is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final float[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of primitive ints is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final int[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of primitive longs is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final long[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of Objects is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final Object[] array) {
return isArrayEmpty(array);
}
/**
* Checks if an array of primitive shorts is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
* @since 2.1
*/
public static boolean isEmpty(final short[] array) {
return isArrayEmpty(array);
}
/**
* Returns the length of the specified array.
* This method can deal with {@link Object} arrays and with primitive arrays.
*
* If the input array is {@code null}, {@code 0} is returned.
*
*
* ArrayUtils.getLength(null) = 0
* ArrayUtils.getLength([]) = 0
* ArrayUtils.getLength([null]) = 1
* ArrayUtils.getLength([true, false]) = 2
* ArrayUtils.getLength([1, 2, 3]) = 3
* ArrayUtils.getLength(["a", "b", "c"]) = 3
*
*
* @param array the array to retrieve the length from, may be null
* @return The length of the array, or {@code 0} if the array is {@code null}
* @throws IllegalArgumentException if the object argument is not an array.
* @since 2.1
*/
public static int getLength(final Object array) {
return array != null ? Array.getLength(array) : 0;
}
/**
* Checks if an array is empty or {@code null}.
*
* @param array the array to test
* @return {@code true} if the array is empty or {@code null}
*/
private static boolean isArrayEmpty(final Object array) {
return getLength(array) == 0;
}
}