Defensive programming technique to change a null reference to an empty one. - Android java.lang.reflect

Description

Defensive programming technique to change a null reference to an empty one.

Demo Code

/*/*  w ww .j ava2s  . co  m*/
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 com.java2s;

public class Main {
    /**
     * An empty immutable {@code Object} array.
     */
    public static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
    /**
     * An empty immutable {@code Class} array.
     */
    public static final Class<?>[] EMPTY_CLASS_ARRAY = new Class[0];
    /**
     * An empty immutable {@code String} array.
     */
    public static final String[] EMPTY_STRING_ARRAY = new String[0];
    /**
     * An empty immutable {@code long} array.
     */
    public static final long[] EMPTY_LONG_ARRAY = new long[0];
    /**
     * An empty immutable {@code Long} array.
     */
    public static final Long[] EMPTY_LONG_OBJECT_ARRAY = new Long[0];
    /**
     * An empty immutable {@code int} array.
     */
    public static final int[] EMPTY_INT_ARRAY = new int[0];
    /**
     * An empty immutable {@code Integer} array.
     */
    public static final Integer[] EMPTY_INTEGER_OBJECT_ARRAY = new Integer[0];
    /**
     * An empty immutable {@code short} array.
     */
    public static final short[] EMPTY_SHORT_ARRAY = new short[0];
    /**
     * An empty immutable {@code Short} array.
     */
    public static final Short[] EMPTY_SHORT_OBJECT_ARRAY = new Short[0];
    /**
     * An empty immutable {@code byte} array.
     */
    public static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
    /**
     * An empty immutable {@code Byte} array.
     */
    public static final Byte[] EMPTY_BYTE_OBJECT_ARRAY = new Byte[0];
    /**
     * An empty immutable {@code double} array.
     */
    public static final double[] EMPTY_DOUBLE_ARRAY = new double[0];
    /**
     * An empty immutable {@code Double} array.
     */
    public static final Double[] EMPTY_DOUBLE_OBJECT_ARRAY = new Double[0];
    /**
     * An empty immutable {@code float} array.
     */
    public static final float[] EMPTY_FLOAT_ARRAY = new float[0];
    /**
     * An empty immutable {@code Float} array.
     */
    public static final Float[] EMPTY_FLOAT_OBJECT_ARRAY = new Float[0];
    /**
     * An empty immutable {@code boolean} array.
     */
    public static final boolean[] EMPTY_BOOLEAN_ARRAY = new boolean[0];
    /**
     * An empty immutable {@code Boolean} array.
     */
    public static final Boolean[] EMPTY_BOOLEAN_OBJECT_ARRAY = new Boolean[0];
    /**
     * An empty immutable {@code char} array.
     */
    public static final char[] EMPTY_CHAR_ARRAY = new char[0];
    /**
     * An empty immutable {@code Character} array.
     */
    public static final Character[] EMPTY_CHARACTER_OBJECT_ARRAY = new Character[0];

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Object[] nullToEmpty(final Object[] array) {
        if (isEmpty(array)) {
            return EMPTY_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 3.2
     */
    public static Class<?>[] nullToEmpty(final Class<?>[] array) {
        if (isEmpty(array)) {
            return EMPTY_CLASS_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static String[] nullToEmpty(final String[] array) {
        if (isEmpty(array)) {
            return EMPTY_STRING_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static long[] nullToEmpty(final long[] array) {
        if (isEmpty(array)) {
            return EMPTY_LONG_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static int[] nullToEmpty(final int[] array) {
        if (isEmpty(array)) {
            return EMPTY_INT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static short[] nullToEmpty(final short[] array) {
        if (isEmpty(array)) {
            return EMPTY_SHORT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static char[] nullToEmpty(final char[] array) {
        if (isEmpty(array)) {
            return EMPTY_CHAR_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static byte[] nullToEmpty(final byte[] array) {
        if (isEmpty(array)) {
            return EMPTY_BYTE_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static double[] nullToEmpty(final double[] array) {
        if (isEmpty(array)) {
            return EMPTY_DOUBLE_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static float[] nullToEmpty(final float[] array) {
        if (isEmpty(array)) {
            return EMPTY_FLOAT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static boolean[] nullToEmpty(final boolean[] array) {
        if (isEmpty(array)) {
            return EMPTY_BOOLEAN_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Long[] nullToEmpty(final Long[] array) {
        if (isEmpty(array)) {
            return EMPTY_LONG_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Integer[] nullToEmpty(final Integer[] array) {
        if (isEmpty(array)) {
            return EMPTY_INTEGER_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Short[] nullToEmpty(final Short[] array) {
        if (isEmpty(array)) {
            return EMPTY_SHORT_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Character[] nullToEmpty(final Character[] array) {
        if (isEmpty(array)) {
            return EMPTY_CHARACTER_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Byte[] nullToEmpty(final Byte[] array) {
        if (isEmpty(array)) {
            return EMPTY_BYTE_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Double[] nullToEmpty(final Double[] array) {
        if (isEmpty(array)) {
            return EMPTY_DOUBLE_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Float[] nullToEmpty(final Float[] array) {
        if (isEmpty(array)) {
            return EMPTY_FLOAT_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Defensive programming technique to change a {@code null}
     * reference to an empty one.</p>
     *
     * <p>This method returns an empty array for a {@code null} input array.</p>
     *
     * <p>As a memory optimizing technique an empty array passed in will be overridden with
     * the empty {@code public static} references in this class.</p>
     *
     * @param array  the array to check for {@code null} or empty
     * @return the same array, {@code public static} empty array if {@code null} or empty input
     * @since 2.5
     */
    public static Boolean[] nullToEmpty(final Boolean[] array) {
        if (isEmpty(array)) {
            return EMPTY_BOOLEAN_OBJECT_ARRAY;
        }
        return array;
    }

    /**
     * <p>Checks if an array of Objects is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive longs is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive ints is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive shorts is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive chars is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive bytes is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive doubles is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive floats is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }

    /**
     * <p>Checks if an array of primitive booleans is empty or {@code null}.</p>
     *
     * @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 array == null || array.length == 0;
    }
}

• Previous
• Next

Related Tutorials

• Create class from Name
• Get Method from a Class<?> by method Name
• print All Information about a class using reflection
• is Collection By Type
• is Class representing a Basic Type