001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      https://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.lang3;
019
020import java.util.Arrays;
021import java.util.function.IntFunction;
022
023import org.apache.commons.lang3.function.FailableIntFunction;
024
025/**
026 * Fills and returns arrays in the fluent style.
027 *
028 * @since 3.14.0
029 */
030public final class ArrayFill {
031
032    /**
033     * Fills and returns the given array, assigning {@code 0} to each element of the array.
034     * <pre>
035     * ArrayFill.fill(a, (byte) 0);
036     * </pre>
037     *
038     * @param a   The array to fill (may be null).
039     * @return The given array.
040     * @see Arrays#fill(byte[],byte)
041     * @see ArrayFill#fill(byte[],byte)
042     * @since 3.21.0
043     */
044    public static byte[] clear(final byte[] a) {
045        return fill(a, (byte) 0);
046    }
047
048    /**
049     * Fills and returns the given array, assigning {@code '\0'} to each element of the array.
050     * <p>
051     * Equivalent to:
052     * </p>
053     * <pre>
054     * ArrayFill.fill(a, '\0'); // and not '0'!
055     * </pre>
056     *
057     * @param a   The array to fill (may be null).
058     * @return The given array.
059     * @see Arrays#fill(char[],char)
060     * @see ArrayFill#fill(char[],char)
061     * @see CharUtils#NUL
062     * @since 3.21.0
063     */
064    public static char[] clear(final char[] a) {
065        return fill(a, CharUtils.NUL); // and not '0'!
066    }
067
068    /**
069     * Fills and returns the given array, assigning {@code '\0'} to each element of the array.
070     * <p>
071     * Equivalent to:
072     * </p>
073     * <pre>
074     * ArrayFill.fill(a, fromIndex, toIndex, '\0'); // and not '0'!
075     * </pre>
076     *
077     * @param a         The array to fill (may be null).
078     * @param fromIndex The index of the first element (inclusive) to be filled with {@code '\0'}.
079     * @param toIndex   The index of the last element (exclusive) to be filled with {@code '\0'}.
080     * @return The given array.
081     * @see Arrays#fill(char[], int, int, char)
082     * @since 3.21.0
083     */
084    public static char[] clear(final char[] a, final int fromIndex, final int toIndex) {
085        return fill(a, fromIndex, toIndex, CharUtils.NUL);
086    }
087
088    /**
089     * Fills and returns the given array, assigning the given {@code boolean} value to each element of the array.
090     *
091     * @param a   The array to fill (may be null).
092     * @param val The value to store in all elements of the array.
093     * @return The given array.
094     * @see Arrays#fill(boolean[],boolean)
095     * @since 3.18.0
096     */
097    public static boolean[] fill(final boolean[] a, final boolean val) {
098        if (a != null) {
099            Arrays.fill(a, val);
100        }
101        return a;
102    }
103
104    /**
105     * Fills and returns the given array, assigning the given {@code byte} value to each element of the array.
106     *
107     * @param a   The array to fill (may be null).
108     * @param val The value to store in all elements of the array.
109     * @return The given array.
110     * @see Arrays#fill(byte[],byte)
111     */
112    public static byte[] fill(final byte[] a, final byte val) {
113        if (a != null) {
114            Arrays.fill(a, val);
115        }
116        return a;
117    }
118
119    /**
120     * Fills and returns the given array, assigning the given {@code char} value to each element of the array.
121     *
122     * @param a   The array to fill (may be null).
123     * @param val The value to store in all elements of the array.
124     * @return The given array.
125     * @see Arrays#fill(char[],char)
126     */
127    public static char[] fill(final char[] a, final char val) {
128        if (a != null) {
129            Arrays.fill(a, val);
130        }
131        return a;
132    }
133
134    /**
135     * Fills and returns the given array, assigning the given {@code char} value to each element of the array.
136     *
137     * @param a         The array to fill (may be null).
138     * @param val       The value to store in all elements of the array.
139     * @param fromIndex The index of the first element (inclusive) to be filled with the specified value.
140     * @param toIndex   The index of the last element (exclusive) to be filled with the specified value.
141     * @return The given array.
142     * @see Arrays#fill(char[], int, int, char)
143     * @since 3.21.0
144     */
145    public static char[] fill(final char[] a, final int fromIndex, final int toIndex, final char val) {
146        if (a != null) {
147            Arrays.fill(a, fromIndex, toIndex, val);
148        }
149        return a;
150    }
151
152    /**
153     * Fills and returns the given array, assigning the given {@code double} value to each element of the array.
154     *
155     * @param a   The array to fill (may be null).
156     * @param val The value to store in all elements of the array.
157     * @return The given array.
158     * @see Arrays#fill(double[],double)
159     */
160    public static double[] fill(final double[] a, final double val) {
161        if (a != null) {
162            Arrays.fill(a, val);
163        }
164        return a;
165    }
166
167    /**
168     * Fills and returns the given array, assigning the given {@code float} value to each element of the array.
169     *
170     * @param a   The array to fill (may be null).
171     * @param val The value to store in all elements of the array.
172     * @return The given array.
173     * @see Arrays#fill(float[],float)
174     */
175    public static float[] fill(final float[] a, final float val) {
176        if (a != null) {
177            Arrays.fill(a, val);
178        }
179        return a;
180    }
181
182    /**
183     * Fills and returns the given array, assigning the given {@code int} value to each element of the array.
184     *
185     * @param a   The array to fill (may be null).
186     * @param val The value to store in all elements of the array.
187     * @return The given array.
188     * @see Arrays#fill(int[],int)
189     */
190    public static int[] fill(final int[] a, final int val) {
191        if (a != null) {
192            Arrays.fill(a, val);
193        }
194        return a;
195    }
196
197    /**
198     * Fills and returns the given array, assigning the given {@code long} value to each element of the array.
199     *
200     * @param a   The array to fill (may be null).
201     * @param val The value to store in all elements of the array.
202     * @return The given array.
203     * @see Arrays#fill(long[],long)
204     */
205    public static long[] fill(final long[] a, final long val) {
206        if (a != null) {
207            Arrays.fill(a, val);
208        }
209        return a;
210    }
211
212    /**
213     * Fills and returns the given array, assigning the given {@code short} value to each element of the array.
214     *
215     * @param a   The array to fill (may be null).
216     * @param val The value to store in all elements of the array.
217     * @return The given array.
218     * @see Arrays#fill(short[],short)
219     */
220    public static short[] fill(final short[] a, final short val) {
221        if (a != null) {
222            Arrays.fill(a, val);
223        }
224        return a;
225    }
226
227    /**
228     * Fills and returns the given array, using the provided generator function to compute each element. Like {@link Arrays#setAll(Object[], IntFunction)} with
229     * exception support.
230     * <p>
231     * If the generator function throws an exception, it is relayed to the caller and the array is left in an indeterminate state.
232     * </p>
233     * <p>
234     * If the input array or generator function is null, nothing happens.
235     * </p>
236     *
237     * @param <T>       type of elements of the array.
238     * @param array     array to fill (may be null).
239     * @param generator A function accepting an index and producing the desired value for that position.
240     * @return The input array.
241     * @param <E> The kind of thrown exception or error.
242     * @throws E Thrown by the given {@code generator}.
243     * @see Arrays#setAll(Object[], IntFunction)
244     * @since 3.18.0
245     */
246    public static <T, E extends Throwable> T[] fill(final T[] array, final FailableIntFunction<? extends T, E> generator) throws E {
247        if (array != null && generator != null) {
248            for (int i = 0; i < array.length; i++) {
249                array[i] = generator.apply(i);
250            }
251        }
252        return array;
253    }
254
255    /**
256     * Fills and returns the given array, assigning the given {@code T} value to each element of the array.
257     *
258     * @param <T> The array type.
259     * @param a   The array to fill (may be null).
260     * @param val The value to store in all elements of the array.
261     * @return The given array.
262     * @see Arrays#fill(Object[],Object)
263     */
264    public static <T> T[] fill(final T[] a, final T val) {
265        if (a != null) {
266            Arrays.fill(a, val);
267        }
268        return a;
269    }
270
271    private ArrayFill() {
272        // no instances
273    }
274
275}