| /* | |
| * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved. | |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| * | |
| * This code is free software; you can redistribute it and/or modify it | |
| * under the terms of the GNU General Public License version 2 only, as | |
| * published by the Free Software Foundation. Oracle designates this | |
| * particular file as subject to the "Classpath" exception as provided | |
| * by Oracle in the LICENSE file that accompanied this code. | |
| * | |
| * This code is distributed in the hope that it will be useful, but WITHOUT | |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| * version 2 for more details (a copy is included in the LICENSE file that | |
| * accompanied this code). | |
| * | |
| * You should have received a copy of the GNU General Public License version | |
| * 2 along with this work; if not, write to the Free Software Foundation, | |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| * | |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| * or visit www.oracle.com if you need additional information or have any | |
| * questions. | |
| */ | |
| package java.lang; | |
| import java.util.NoSuchElementException; | |
| import java.util.Objects; | |
| import java.util.PrimitiveIterator; | |
| import java.util.Spliterator; | |
| import java.util.Spliterators; | |
| import java.util.function.IntConsumer; | |
| import java.util.stream.IntStream; | |
| import java.util.stream.StreamSupport; | |
| /** | |
| * A {@code CharSequence} is a readable sequence of {@code char} values. This | |
| * interface provides uniform, read-only access to many different kinds of | |
| * {@code char} sequences. | |
| * A {@code char} value represents a character in the <i>Basic | |
| * Multilingual Plane (BMP)</i> or a surrogate. Refer to <a | |
| * href="Character.html#unicode">Unicode Character Representation</a> for details. | |
| * | |
| * <p> This interface does not refine the general contracts of the {@link | |
| * java.lang.Object#equals(java.lang.Object) equals} and {@link | |
| * java.lang.Object#hashCode() hashCode} methods. The result of testing two objects | |
| * that implement {@code CharSequence} for equality is therefore, in general, undefined. | |
| * Each object may be implemented by a different class, and there | |
| * is no guarantee that each class will be capable of testing its instances | |
| * for equality with those of the other. It is therefore inappropriate to use | |
| * arbitrary {@code CharSequence} instances as elements in a set or as keys in | |
| * a map. </p> | |
| * | |
| * @author Mike McCloskey | |
| * @since 1.4 | |
| */ | |
| public interface CharSequence { | |
| /** | |
| * Returns the length of this character sequence. The length is the number | |
| * of 16-bit {@code char}s in the sequence. | |
| * | |
| * @return the number of {@code char}s in this sequence | |
| */ | |
| int length(); | |
| /** | |
| * Returns the {@code char} value at the specified index. An index ranges from zero | |
| * to {@code length() - 1}. The first {@code char} value of the sequence is at | |
| * index zero, the next at index one, and so on, as for array | |
| * indexing. | |
| * | |
| * <p>If the {@code char} value specified by the index is a | |
| * {@linkplain Character##unicode surrogate}, the surrogate value | |
| * is returned. | |
| * | |
| * @param index the index of the {@code char} value to be returned | |
| * | |
| * @return the specified {@code char} value | |
| * | |
| * @throws IndexOutOfBoundsException | |
| * if the {@code index} argument is negative or not less than | |
| * {@code length()} | |
| */ | |
| char charAt(int index); | |
| /** | |
| * Returns {@code true} if this character sequence is empty. | |
| * | |
| * @implSpec | |
| * The default implementation returns the result of calling {@code length() == 0}. | |
| * | |
| * @return {@code true} if {@link #length()} is {@code 0}, otherwise | |
| * {@code false} | |
| * | |
| * @since 15 | |
| */ | |
| default boolean isEmpty() { | |
| return this.length() == 0; | |
| } | |
| /** | |
| * Returns a {@code CharSequence} that is a subsequence of this sequence. | |
| * The subsequence starts with the {@code char} value at the specified index and | |
| * ends with the {@code char} value at index {@code end - 1}. The length | |
| * (in {@code char}s) of the | |
| * returned sequence is {@code end - start}, so if {@code start == end} | |
| * then an empty sequence is returned. | |
| * | |
| * @param start the start index, inclusive | |
| * @param end the end index, exclusive | |
| * | |
| * @return the specified subsequence | |
| * | |
| * @throws IndexOutOfBoundsException | |
| * if {@code start} or {@code end} are negative, | |
| * if {@code end} is greater than {@code length()}, | |
| * or if {@code start} is greater than {@code end} | |
| */ | |
| CharSequence subSequence(int start, int end); | |
| /** | |
| * Returns a string containing the characters in this sequence in the same | |
| * order as this sequence. The length of the string will be the length of | |
| * this sequence. | |
| * | |
| * @return a string consisting of exactly this sequence of characters | |
| */ | |
| public String toString(); | |
| /** | |
| * Returns a stream of {@code int} zero-extending the {@code char} values | |
| * from this sequence. Any char which maps to a | |
| * {@linkplain Character##unicode surrogate code point} is passed | |
| * through uninterpreted. | |
| * | |
| * <p>The stream binds to this sequence when the terminal stream operation | |
| * commences (specifically, for mutable sequences the spliterator for the | |
| * stream is <a href="../util/Spliterator.html#binding"><em>late-binding</em></a>). | |
| * If the sequence is modified during that operation then the result is | |
| * undefined. | |
| * | |
| * @return an IntStream of char values from this sequence | |
| * @since 1.8 | |
| */ | |
| public default IntStream chars() { | |
| class CharIterator implements PrimitiveIterator.OfInt { | |
| int cur = 0; | |
| public boolean hasNext() { | |
| return cur < length(); | |
| } | |
| public int nextInt() { | |
| if (hasNext()) { | |
| return charAt(cur++); | |
| } else { | |
| throw new NoSuchElementException(); | |
| } | |
| } | |
| @Override | |
| public void forEachRemaining(IntConsumer block) { | |
| for (; cur < length(); cur++) { | |
| block.accept(charAt(cur)); | |
| } | |
| } | |
| } | |
| return StreamSupport.intStream(() -> | |
| Spliterators.spliterator( | |
| new CharIterator(), | |
| length(), | |
| Spliterator.ORDERED), | |
| Spliterator.SUBSIZED | Spliterator.SIZED | Spliterator.ORDERED, | |
| false); | |
| } | |
| /** | |
| * Returns a stream of code point values from this sequence. Any surrogate | |
| * pairs encountered in the sequence are combined as if by {@linkplain | |
| * Character#toCodePoint Character.toCodePoint} and the result is passed | |
| * to the stream. Any other code units, including ordinary BMP characters, | |
| * unpaired surrogates, and undefined code units, are zero-extended to | |
| * {@code int} values which are then passed to the stream. | |
| * | |
| * <p>The stream binds to this sequence when the terminal stream operation | |
| * commences (specifically, for mutable sequences the spliterator for the | |
| * stream is <a href="../util/Spliterator.html#binding"><em>late-binding</em></a>). | |
| * If the sequence is modified during that operation then the result is | |
| * undefined. | |
| * | |
| * @return an IntStream of Unicode code points from this sequence | |
| * @since 1.8 | |
| */ | |
| public default IntStream codePoints() { | |
| class CodePointIterator implements PrimitiveIterator.OfInt { | |
| int cur = 0; | |
| @Override | |
| public void forEachRemaining(IntConsumer block) { | |
| final int length = length(); | |
| int i = cur; | |
| try { | |
| while (i < length) { | |
| char c1 = charAt(i++); | |
| if (!Character.isHighSurrogate(c1) || i >= length) { | |
| block.accept(c1); | |
| } else { | |
| char c2 = charAt(i); | |
| if (Character.isLowSurrogate(c2)) { | |
| i++; | |
| block.accept(Character.toCodePoint(c1, c2)); | |
| } else { | |
| block.accept(c1); | |
| } | |
| } | |
| } | |
| } finally { | |
| cur = i; | |
| } | |
| } | |
| public boolean hasNext() { | |
| return cur < length(); | |
| } | |
| public int nextInt() { | |
| final int length = length(); | |
| if (cur >= length) { | |
| throw new NoSuchElementException(); | |
| } | |
| char c1 = charAt(cur++); | |
| if (Character.isHighSurrogate(c1) && cur < length) { | |
| char c2 = charAt(cur); | |
| if (Character.isLowSurrogate(c2)) { | |
| cur++; | |
| return Character.toCodePoint(c1, c2); | |
| } | |
| } | |
| return c1; | |
| } | |
| } | |
| return StreamSupport.intStream(() -> | |
| Spliterators.spliteratorUnknownSize( | |
| new CodePointIterator(), | |
| Spliterator.ORDERED), | |
| Spliterator.ORDERED, | |
| false); | |
| } | |
| /** | |
| * Compares two {@code CharSequence} instances lexicographically. Returns a | |
| * negative value, zero, or a positive value if the first sequence is lexicographically | |
| * less than, equal to, or greater than the second, respectively. | |
| * | |
| * <p> | |
| * The lexicographical ordering of {@code CharSequence} is defined as follows. | |
| * Consider a {@code CharSequence} <i>cs</i> of length <i>len</i> to be a | |
| * sequence of char values, <i>cs[0]</i> to <i>cs[len-1]</i>. Suppose <i>k</i> | |
| * is the lowest index at which the corresponding char values from each sequence | |
| * differ. The lexicographic ordering of the sequences is determined by a numeric | |
| * comparison of the char values <i>cs1[k]</i> with <i>cs2[k]</i>. If there is | |
| * no such index <i>k</i>, the shorter sequence is considered lexicographically | |
| * less than the other. If the sequences have the same length, the sequences are | |
| * considered lexicographically equal. | |
| * | |
| * | |
| * @param cs1 the first {@code CharSequence} | |
| * @param cs2 the second {@code CharSequence} | |
| * | |
| * @return the value {@code 0} if the two {@code CharSequence} are equal; | |
| * a negative integer if the first {@code CharSequence} | |
| * is lexicographically less than the second; or a | |
| * positive integer if the first {@code CharSequence} is | |
| * lexicographically greater than the second. | |
| * | |
| * @since 11 | |
| */ | |
| @SuppressWarnings("unchecked") | |
| public static int compare(CharSequence cs1, CharSequence cs2) { | |
| if (Objects.requireNonNull(cs1) == Objects.requireNonNull(cs2)) { | |
| return 0; | |
| } | |
| if (cs1.getClass() == cs2.getClass() && cs1 instanceof Comparable) { | |
| return ((Comparable<Object>) cs1).compareTo(cs2); | |
| } | |
| for (int i = 0, len = Math.min(cs1.length(), cs2.length()); i < len; i++) { | |
| char a = cs1.charAt(i); | |
| char b = cs2.charAt(i); | |
| if (a != b) { | |
| return a - b; | |
| } | |
| } | |
| return cs1.length() - cs2.length(); | |
| } | |
| /** | |
| * Copies characters from this sequence into the given destination array. | |
| * The first character to be copied is at index {@code srcBegin}; the last | |
| * character to be copied is at index {@code srcEnd-1}. The total number of | |
| * characters to be copied is {@code srcEnd-srcBegin}. The | |
| * characters are copied into the subarray of {@code dst} starting | |
| * at index {@code dstBegin} and ending at index: | |
| * <pre>{@code | |
| * dstbegin + (srcEnd-srcBegin) - 1 | |
| * }</pre> | |
| * | |
| * @param srcBegin start copying at this offset. | |
| * @param srcEnd stop copying at this offset. | |
| * @param dst the array to copy the data into. | |
| * @param dstBegin offset into {@code dst}. | |
| * @throws IndexOutOfBoundsException if any of the following is true: | |
| * <ul> | |
| * <li>{@code srcBegin} is negative | |
| * <li>{@code dstBegin} is negative | |
| * <li>the {@code srcBegin} argument is greater than | |
| * the {@code srcEnd} argument. | |
| * <li>{@code srcEnd} is greater than | |
| * {@code this.length()}. | |
| * <li>{@code dstBegin+srcEnd-srcBegin} is greater than | |
| * {@code dst.length} | |
| * </ul> | |
| * @throws NullPointerException if {@code dst} is {@code null} | |
| * | |
| * @implSpec | |
| * The default implementation invokes {@link #charAt(int index)} in a loop | |
| * iterating {@code index} from {@code srcBegin} to {@code srcEnd-1}. | |
| * Concurrent truncation of this character sequence can throw | |
| * {@code IndexOutOfBoundsException}. In this case, some characters, but not | |
| * all, may be already transferred. | |
| * | |
| * @since 25 | |
| */ | |
| public default void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) { | |
| Objects.checkFromToIndex(srcBegin, srcEnd, length()); | |
| Objects.checkIndex(dstBegin, dst.length - (srcEnd - srcBegin) + 1); | |
| while (srcBegin < srcEnd) | |
| dst[dstBegin++] = charAt(srcBegin++); | |
| } | |
| } |