| /* |
| * Copyright (C) 2008 The Guava Authors |
| * |
| * 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 com.google.common.primitives; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkElementIndex; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkPositionIndexes; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.annotations.GwtCompatible; |
| import com.google.common.annotations.GwtIncompatible; |
| import com.google.common.base.Converter; |
| import java.io.Serializable; |
| import java.util.AbstractList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Comparator; |
| import java.util.List; |
| import java.util.RandomAccess; |
| import org.checkerframework.checker.nullness.compatqual.NullableDecl; |
| |
| /** |
| * Static utility methods pertaining to {@code int} primitives, that are not already found in either |
| * {@link Integer} or {@link Arrays}. |
| * |
| * <p>See the Guava User Guide article on <a |
| * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>. |
| * |
| * @author Kevin Bourrillion |
| * @since 1.0 |
| */ |
| @GwtCompatible(emulated = true) |
| public final class Ints extends IntsMethodsForWeb { |
| private Ints() {} |
| |
| /** |
| * The number of bytes required to represent a primitive {@code int} value. |
| * |
| * <p><b>Java 8 users:</b> use {@link Integer#BYTES} instead. |
| */ |
| public static final int BYTES = Integer.SIZE / Byte.SIZE; |
| |
| /** |
| * The largest power of two that can be represented as an {@code int}. |
| * |
| * @since 10.0 |
| */ |
| public static final int MAX_POWER_OF_TWO = 1 << (Integer.SIZE - 2); |
| |
| /** |
| * Returns a hash code for {@code value}; equal to the result of invoking {@code ((Integer) |
| * value).hashCode()}. |
| * |
| * <p><b>Java 8 users:</b> use {@link Integer#hashCode(int)} instead. |
| * |
| * @param value a primitive {@code int} value |
| * @return a hash code for the value |
| */ |
| public static int hashCode(int value) { |
| return value; |
| } |
| |
| /** |
| * Returns the {@code int} value that is equal to {@code value}, if possible. |
| * |
| * @param value any value in the range of the {@code int} type |
| * @return the {@code int} value that equals {@code value} |
| * @throws IllegalArgumentException if {@code value} is greater than {@link Integer#MAX_VALUE} or |
| * less than {@link Integer#MIN_VALUE} |
| */ |
| public static int checkedCast(long value) { |
| int result = (int) value; |
| checkArgument(result == value, "Out of range: %s", value); |
| return result; |
| } |
| |
| /** |
| * Returns the {@code int} nearest in value to {@code value}. |
| * |
| * @param value any {@code long} value |
| * @return the same value cast to {@code int} if it is in the range of the {@code int} type, |
| * {@link Integer#MAX_VALUE} if it is too large, or {@link Integer#MIN_VALUE} if it is too |
| * small |
| */ |
| public static int saturatedCast(long value) { |
| if (value > Integer.MAX_VALUE) { |
| return Integer.MAX_VALUE; |
| } |
| if (value < Integer.MIN_VALUE) { |
| return Integer.MIN_VALUE; |
| } |
| return (int) value; |
| } |
| |
| /** |
| * Compares the two specified {@code int} values. The sign of the value returned is the same as |
| * that of {@code ((Integer) a).compareTo(b)}. |
| * |
| * <p><b>Note for Java 7 and later:</b> this method should be treated as deprecated; use the |
| * equivalent {@link Integer#compare} method instead. |
| * |
| * @param a the first {@code int} to compare |
| * @param b the second {@code int} to compare |
| * @return a negative value if {@code a} is less than {@code b}; a positive value if {@code a} is |
| * greater than {@code b}; or zero if they are equal |
| */ |
| public static int compare(int a, int b) { |
| return (a < b) ? -1 : ((a > b) ? 1 : 0); |
| } |
| |
| /** |
| * Returns {@code true} if {@code target} is present as an element anywhere in {@code array}. |
| * |
| * @param array an array of {@code int} values, possibly empty |
| * @param target a primitive {@code int} value |
| * @return {@code true} if {@code array[i] == target} for some value of {@code i} |
| */ |
| public static boolean contains(int[] array, int target) { |
| for (int value : array) { |
| if (value == target) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Returns the index of the first appearance of the value {@code target} in {@code array}. |
| * |
| * @param array an array of {@code int} values, possibly empty |
| * @param target a primitive {@code int} value |
| * @return the least index {@code i} for which {@code array[i] == target}, or {@code -1} if no |
| * such index exists. |
| */ |
| public static int indexOf(int[] array, int target) { |
| return indexOf(array, target, 0, array.length); |
| } |
| |
| // TODO(kevinb): consider making this public |
| private static int indexOf(int[] array, int target, int start, int end) { |
| for (int i = start; i < end; i++) { |
| if (array[i] == target) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| /** |
| * Returns the start position of the first occurrence of the specified {@code target} within |
| * {@code array}, or {@code -1} if there is no such occurrence. |
| * |
| * <p>More formally, returns the lowest index {@code i} such that {@code Arrays.copyOfRange(array, |
| * i, i + target.length)} contains exactly the same elements as {@code target}. |
| * |
| * @param array the array to search for the sequence {@code target} |
| * @param target the array to search for as a sub-sequence of {@code array} |
| */ |
| public static int indexOf(int[] array, int[] target) { |
| checkNotNull(array, "array"); |
| checkNotNull(target, "target"); |
| if (target.length == 0) { |
| return 0; |
| } |
| |
| outer: |
| for (int i = 0; i < array.length - target.length + 1; i++) { |
| for (int j = 0; j < target.length; j++) { |
| if (array[i + j] != target[j]) { |
| continue outer; |
| } |
| } |
| return i; |
| } |
| return -1; |
| } |
| |
| /** |
| * Returns the index of the last appearance of the value {@code target} in {@code array}. |
| * |
| * @param array an array of {@code int} values, possibly empty |
| * @param target a primitive {@code int} value |
| * @return the greatest index {@code i} for which {@code array[i] == target}, or {@code -1} if no |
| * such index exists. |
| */ |
| public static int lastIndexOf(int[] array, int target) { |
| return lastIndexOf(array, target, 0, array.length); |
| } |
| |
| // TODO(kevinb): consider making this public |
| private static int lastIndexOf(int[] array, int target, int start, int end) { |
| for (int i = end - 1; i >= start; i--) { |
| if (array[i] == target) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| /** |
| * Returns the least value present in {@code array}. |
| * |
| * @param array a <i>nonempty</i> array of {@code int} values |
| * @return the value present in {@code array} that is less than or equal to every other value in |
| * the array |
| * @throws IllegalArgumentException if {@code array} is empty |
| */ |
| @GwtIncompatible( |
| "Available in GWT! Annotation is to avoid conflict with GWT specialization of base class.") |
| public static int min(int... array) { |
| checkArgument(array.length > 0); |
| int min = array[0]; |
| for (int i = 1; i < array.length; i++) { |
| if (array[i] < min) { |
| min = array[i]; |
| } |
| } |
| return min; |
| } |
| |
| /** |
| * Returns the greatest value present in {@code array}. |
| * |
| * @param array a <i>nonempty</i> array of {@code int} values |
| * @return the value present in {@code array} that is greater than or equal to every other value |
| * in the array |
| * @throws IllegalArgumentException if {@code array} is empty |
| */ |
| @GwtIncompatible( |
| "Available in GWT! Annotation is to avoid conflict with GWT specialization of base class.") |
| public static int max(int... array) { |
| checkArgument(array.length > 0); |
| int max = array[0]; |
| for (int i = 1; i < array.length; i++) { |
| if (array[i] > max) { |
| max = array[i]; |
| } |
| } |
| return max; |
| } |
| |
| /** |
| * Returns the value nearest to {@code value} which is within the closed range {@code [min..max]}. |
| * |
| * <p>If {@code value} is within the range {@code [min..max]}, {@code value} is returned |
| * unchanged. If {@code value} is less than {@code min}, {@code min} is returned, and if {@code |
| * value} is greater than {@code max}, {@code max} is returned. |
| * |
| * @param value the {@code int} value to constrain |
| * @param min the lower bound (inclusive) of the range to constrain {@code value} to |
| * @param max the upper bound (inclusive) of the range to constrain {@code value} to |
| * @throws IllegalArgumentException if {@code min > max} |
| * @since 21.0 |
| */ |
| @Beta |
| public static int constrainToRange(int value, int min, int max) { |
| checkArgument(min <= max, "min (%s) must be less than or equal to max (%s)", min, max); |
| return Math.min(Math.max(value, min), max); |
| } |
| |
| /** |
| * Returns the values from each provided array combined into a single array. For example, {@code |
| * concat(new int[] {a, b}, new int[] {}, new int[] {c}} returns the array {@code {a, b, c}}. |
| * |
| * @param arrays zero or more {@code int} arrays |
| * @return a single array containing all the values from the source arrays, in order |
| */ |
| public static int[] concat(int[]... arrays) { |
| int length = 0; |
| for (int[] array : arrays) { |
| length += array.length; |
| } |
| int[] result = new int[length]; |
| int pos = 0; |
| for (int[] array : arrays) { |
| System.arraycopy(array, 0, result, pos, array.length); |
| pos += array.length; |
| } |
| return result; |
| } |
| |
| /** |
| * Returns a big-endian representation of {@code value} in a 4-element byte array; equivalent to |
| * {@code ByteBuffer.allocate(4).putInt(value).array()}. For example, the input value {@code |
| * 0x12131415} would yield the byte array {@code {0x12, 0x13, 0x14, 0x15}}. |
| * |
| * <p>If you need to convert and concatenate several values (possibly even of different types), |
| * use a shared {@link java.nio.ByteBuffer} instance, or use {@link |
| * com.google.common.io.ByteStreams#newDataOutput()} to get a growable buffer. |
| */ |
| public static byte[] toByteArray(int value) { |
| return new byte[] { |
| (byte) (value >> 24), (byte) (value >> 16), (byte) (value >> 8), (byte) value |
| }; |
| } |
| |
| /** |
| * Returns the {@code int} value whose big-endian representation is stored in the first 4 bytes of |
| * {@code bytes}; equivalent to {@code ByteBuffer.wrap(bytes).getInt()}. For example, the input |
| * byte array {@code {0x12, 0x13, 0x14, 0x15, 0x33}} would yield the {@code int} value {@code |
| * 0x12131415}. |
| * |
| * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that library exposes much more |
| * flexibility at little cost in readability. |
| * |
| * @throws IllegalArgumentException if {@code bytes} has fewer than 4 elements |
| */ |
| public static int fromByteArray(byte[] bytes) { |
| checkArgument(bytes.length >= BYTES, "array too small: %s < %s", bytes.length, BYTES); |
| return fromBytes(bytes[0], bytes[1], bytes[2], bytes[3]); |
| } |
| |
| /** |
| * Returns the {@code int} value whose byte representation is the given 4 bytes, in big-endian |
| * order; equivalent to {@code Ints.fromByteArray(new byte[] {b1, b2, b3, b4})}. |
| * |
| * @since 7.0 |
| */ |
| public static int fromBytes(byte b1, byte b2, byte b3, byte b4) { |
| return b1 << 24 | (b2 & 0xFF) << 16 | (b3 & 0xFF) << 8 | (b4 & 0xFF); |
| } |
| |
| private static final class IntConverter extends Converter<String, Integer> |
| implements Serializable { |
| static final IntConverter INSTANCE = new IntConverter(); |
| |
| @Override |
| protected Integer doForward(String value) { |
| return Integer.decode(value); |
| } |
| |
| @Override |
| protected String doBackward(Integer value) { |
| return value.toString(); |
| } |
| |
| @Override |
| public String toString() { |
| return "Ints.stringConverter()"; |
| } |
| |
| private Object readResolve() { |
| return INSTANCE; |
| } |
| |
| private static final long serialVersionUID = 1; |
| } |
| |
| /** |
| * Returns a serializable converter object that converts between strings and integers using {@link |
| * Integer#decode} and {@link Integer#toString()}. The returned converter throws {@link |
| * NumberFormatException} if the input string is invalid. |
| * |
| * <p><b>Warning:</b> please see {@link Integer#decode} to understand exactly how strings are |
| * parsed. For example, the string {@code "0123"} is treated as <i>octal</i> and converted to the |
| * value {@code 83}. |
| * |
| * @since 16.0 |
| */ |
| @Beta |
| public static Converter<String, Integer> stringConverter() { |
| return IntConverter.INSTANCE; |
| } |
| |
| /** |
| * Returns an array containing the same values as {@code array}, but guaranteed to be of a |
| * specified minimum length. If {@code array} already has a length of at least {@code minLength}, |
| * it is returned directly. Otherwise, a new array of size {@code minLength + padding} is |
| * returned, containing the values of {@code array}, and zeroes in the remaining places. |
| * |
| * @param array the source array |
| * @param minLength the minimum length the returned array must guarantee |
| * @param padding an extra amount to "grow" the array by if growth is necessary |
| * @throws IllegalArgumentException if {@code minLength} or {@code padding} is negative |
| * @return an array containing the values of {@code array}, with guaranteed minimum length {@code |
| * minLength} |
| */ |
| public static int[] ensureCapacity(int[] array, int minLength, int padding) { |
| checkArgument(minLength >= 0, "Invalid minLength: %s", minLength); |
| checkArgument(padding >= 0, "Invalid padding: %s", padding); |
| return (array.length < minLength) ? Arrays.copyOf(array, minLength + padding) : array; |
| } |
| |
| /** |
| * Returns a string containing the supplied {@code int} values separated by {@code separator}. For |
| * example, {@code join("-", 1, 2, 3)} returns the string {@code "1-2-3"}. |
| * |
| * @param separator the text that should appear between consecutive values in the resulting string |
| * (but not at the start or end) |
| * @param array an array of {@code int} values, possibly empty |
| */ |
| public static String join(String separator, int... array) { |
| checkNotNull(separator); |
| if (array.length == 0) { |
| return ""; |
| } |
| |
| // For pre-sizing a builder, just get the right order of magnitude |
| StringBuilder builder = new StringBuilder(array.length * 5); |
| builder.append(array[0]); |
| for (int i = 1; i < array.length; i++) { |
| builder.append(separator).append(array[i]); |
| } |
| return builder.toString(); |
| } |
| |
| /** |
| * Returns a comparator that compares two {@code int} arrays <a |
| * href="http://en.wikipedia.org/wiki/Lexicographical_order">lexicographically</a>. That is, it |
| * compares, using {@link #compare(int, int)}), the first pair of values that follow any common |
| * prefix, or when one array is a prefix of the other, treats the shorter array as the lesser. For |
| * example, {@code [] < [1] < [1, 2] < [2]}. |
| * |
| * <p>The returned comparator is inconsistent with {@link Object#equals(Object)} (since arrays |
| * support only identity equality), but it is consistent with {@link Arrays#equals(int[], int[])}. |
| * |
| * @since 2.0 |
| */ |
| public static Comparator<int[]> lexicographicalComparator() { |
| return LexicographicalComparator.INSTANCE; |
| } |
| |
| private enum LexicographicalComparator implements Comparator<int[]> { |
| INSTANCE; |
| |
| @Override |
| public int compare(int[] left, int[] right) { |
| int minLength = Math.min(left.length, right.length); |
| for (int i = 0; i < minLength; i++) { |
| int result = Ints.compare(left[i], right[i]); |
| if (result != 0) { |
| return result; |
| } |
| } |
| return left.length - right.length; |
| } |
| |
| @Override |
| public String toString() { |
| return "Ints.lexicographicalComparator()"; |
| } |
| } |
| |
| /** |
| * Sorts the elements of {@code array} in descending order. |
| * |
| * @since 23.1 |
| */ |
| public static void sortDescending(int[] array) { |
| checkNotNull(array); |
| sortDescending(array, 0, array.length); |
| } |
| |
| /** |
| * Sorts the elements of {@code array} between {@code fromIndex} inclusive and {@code toIndex} |
| * exclusive in descending order. |
| * |
| * @since 23.1 |
| */ |
| public static void sortDescending(int[] array, int fromIndex, int toIndex) { |
| checkNotNull(array); |
| checkPositionIndexes(fromIndex, toIndex, array.length); |
| Arrays.sort(array, fromIndex, toIndex); |
| reverse(array, fromIndex, toIndex); |
| } |
| |
| /** |
| * Reverses the elements of {@code array}. This is equivalent to {@code |
| * Collections.reverse(Ints.asList(array))}, but is likely to be more efficient. |
| * |
| * @since 23.1 |
| */ |
| public static void reverse(int[] array) { |
| checkNotNull(array); |
| reverse(array, 0, array.length); |
| } |
| |
| /** |
| * Reverses the elements of {@code array} between {@code fromIndex} inclusive and {@code toIndex} |
| * exclusive. This is equivalent to {@code |
| * Collections.reverse(Ints.asList(array).subList(fromIndex, toIndex))}, but is likely to be more |
| * efficient. |
| * |
| * @throws IndexOutOfBoundsException if {@code fromIndex < 0}, {@code toIndex > array.length}, or |
| * {@code toIndex > fromIndex} |
| * @since 23.1 |
| */ |
| public static void reverse(int[] array, int fromIndex, int toIndex) { |
| checkNotNull(array); |
| checkPositionIndexes(fromIndex, toIndex, array.length); |
| for (int i = fromIndex, j = toIndex - 1; i < j; i++, j--) { |
| int tmp = array[i]; |
| array[i] = array[j]; |
| array[j] = tmp; |
| } |
| } |
| |
| /** |
| * Returns an array containing each value of {@code collection}, converted to a {@code int} value |
| * in the manner of {@link Number#intValue}. |
| * |
| * <p>Elements are copied from the argument collection as if by {@code collection.toArray()}. |
| * Calling this method is as thread-safe as calling that method. |
| * |
| * @param collection a collection of {@code Number} instances |
| * @return an array containing the same values as {@code collection}, in the same order, converted |
| * to primitives |
| * @throws NullPointerException if {@code collection} or any of its elements is null |
| * @since 1.0 (parameter was {@code Collection<Integer>} before 12.0) |
| */ |
| public static int[] toArray(Collection<? extends Number> collection) { |
| if (collection instanceof IntArrayAsList) { |
| return ((IntArrayAsList) collection).toIntArray(); |
| } |
| |
| Object[] boxedArray = collection.toArray(); |
| int len = boxedArray.length; |
| int[] array = new int[len]; |
| for (int i = 0; i < len; i++) { |
| // checkNotNull for GWT (do not optimize) |
| array[i] = ((Number) checkNotNull(boxedArray[i])).intValue(); |
| } |
| return array; |
| } |
| |
| /** |
| * Returns a fixed-size list backed by the specified array, similar to {@link |
| * Arrays#asList(Object[])}. The list supports {@link List#set(int, Object)}, but any attempt to |
| * set a value to {@code null} will result in a {@link NullPointerException}. |
| * |
| * <p>The returned list maintains the values, but not the identities, of {@code Integer} objects |
| * written to or read from it. For example, whether {@code list.get(0) == list.get(0)} is true for |
| * the returned list is unspecified. |
| * |
| * <p><b>Note:</b> when possible, you should represent your data as an {@link ImmutableIntArray} |
| * instead, which has an {@link ImmutableIntArray#asList asList} view. |
| * |
| * @param backingArray the array to back the list |
| * @return a list view of the array |
| */ |
| public static List<Integer> asList(int... backingArray) { |
| if (backingArray.length == 0) { |
| return Collections.emptyList(); |
| } |
| return new IntArrayAsList(backingArray); |
| } |
| |
| @GwtCompatible |
| private static class IntArrayAsList extends AbstractList<Integer> |
| implements RandomAccess, Serializable { |
| final int[] array; |
| final int start; |
| final int end; |
| |
| IntArrayAsList(int[] array) { |
| this(array, 0, array.length); |
| } |
| |
| IntArrayAsList(int[] array, int start, int end) { |
| this.array = array; |
| this.start = start; |
| this.end = end; |
| } |
| |
| @Override |
| public int size() { |
| return end - start; |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return false; |
| } |
| |
| @Override |
| public Integer get(int index) { |
| checkElementIndex(index, size()); |
| return array[start + index]; |
| } |
| |
| @Override |
| public boolean contains(Object target) { |
| // Overridden to prevent a ton of boxing |
| return (target instanceof Integer) && Ints.indexOf(array, (Integer) target, start, end) != -1; |
| } |
| |
| @Override |
| public int indexOf(Object target) { |
| // Overridden to prevent a ton of boxing |
| if (target instanceof Integer) { |
| int i = Ints.indexOf(array, (Integer) target, start, end); |
| if (i >= 0) { |
| return i - start; |
| } |
| } |
| return -1; |
| } |
| |
| @Override |
| public int lastIndexOf(Object target) { |
| // Overridden to prevent a ton of boxing |
| if (target instanceof Integer) { |
| int i = Ints.lastIndexOf(array, (Integer) target, start, end); |
| if (i >= 0) { |
| return i - start; |
| } |
| } |
| return -1; |
| } |
| |
| @Override |
| public Integer set(int index, Integer element) { |
| checkElementIndex(index, size()); |
| int oldValue = array[start + index]; |
| // checkNotNull for GWT (do not optimize) |
| array[start + index] = checkNotNull(element); |
| return oldValue; |
| } |
| |
| @Override |
| public List<Integer> subList(int fromIndex, int toIndex) { |
| int size = size(); |
| checkPositionIndexes(fromIndex, toIndex, size); |
| if (fromIndex == toIndex) { |
| return Collections.emptyList(); |
| } |
| return new IntArrayAsList(array, start + fromIndex, start + toIndex); |
| } |
| |
| @Override |
| public boolean equals(@NullableDecl Object object) { |
| if (object == this) { |
| return true; |
| } |
| if (object instanceof IntArrayAsList) { |
| IntArrayAsList that = (IntArrayAsList) object; |
| int size = size(); |
| if (that.size() != size) { |
| return false; |
| } |
| for (int i = 0; i < size; i++) { |
| if (array[start + i] != that.array[that.start + i]) { |
| return false; |
| } |
| } |
| return true; |
| } |
| return super.equals(object); |
| } |
| |
| @Override |
| public int hashCode() { |
| int result = 1; |
| for (int i = start; i < end; i++) { |
| result = 31 * result + Ints.hashCode(array[i]); |
| } |
| return result; |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder builder = new StringBuilder(size() * 5); |
| builder.append('[').append(array[start]); |
| for (int i = start + 1; i < end; i++) { |
| builder.append(", ").append(array[i]); |
| } |
| return builder.append(']').toString(); |
| } |
| |
| int[] toIntArray() { |
| return Arrays.copyOfRange(array, start, end); |
| } |
| |
| private static final long serialVersionUID = 0; |
| } |
| |
| /** |
| * Parses the specified string as a signed decimal integer value. The ASCII character {@code '-'} |
| * (<code>'\u002D'</code>) is recognized as the minus sign. |
| * |
| * <p>Unlike {@link Integer#parseInt(String)}, this method returns {@code null} instead of |
| * throwing an exception if parsing fails. Additionally, this method only accepts ASCII digits, |
| * and returns {@code null} if non-ASCII digits are present in the string. |
| * |
| * <p>Note that strings prefixed with ASCII {@code '+'} are rejected, even under JDK 7, despite |
| * the change to {@link Integer#parseInt(String)} for that version. |
| * |
| * @param string the string representation of an integer value |
| * @return the integer value represented by {@code string}, or {@code null} if {@code string} has |
| * a length of zero or cannot be parsed as an integer value |
| * @throws NullPointerException if {@code string} is {@code null} |
| * @since 11.0 |
| */ |
| @Beta |
| @NullableDecl |
| public static Integer tryParse(String string) { |
| return tryParse(string, 10); |
| } |
| |
| /** |
| * Parses the specified string as a signed integer value using the specified radix. The ASCII |
| * character {@code '-'} (<code>'\u002D'</code>) is recognized as the minus sign. |
| * |
| * <p>Unlike {@link Integer#parseInt(String, int)}, this method returns {@code null} instead of |
| * throwing an exception if parsing fails. Additionally, this method only accepts ASCII digits, |
| * and returns {@code null} if non-ASCII digits are present in the string. |
| * |
| * <p>Note that strings prefixed with ASCII {@code '+'} are rejected, even under JDK 7, despite |
| * the change to {@link Integer#parseInt(String, int)} for that version. |
| * |
| * @param string the string representation of an integer value |
| * @param radix the radix to use when parsing |
| * @return the integer value represented by {@code string} using {@code radix}, or {@code null} if |
| * {@code string} has a length of zero or cannot be parsed as an integer value |
| * @throws IllegalArgumentException if {@code radix < Character.MIN_RADIX} or {@code radix > |
| * Character.MAX_RADIX} |
| * @throws NullPointerException if {@code string} is {@code null} |
| * @since 19.0 |
| */ |
| @Beta |
| @NullableDecl |
| public static Integer tryParse(String string, int radix) { |
| Long result = Longs.tryParse(string, radix); |
| if (result == null || result.longValue() != result.intValue()) { |
| return null; |
| } else { |
| return result.intValue(); |
| } |
| } |
| } |