8200377: String::strip, String::stripLeading, String::stripTrailing
Reviewed-by: sundar, rriggs
--- a/src/java.base/share/classes/java/lang/String.java Mon May 14 11:47:03 2018 +0200
+++ b/src/java.base/share/classes/java/lang/String.java Mon May 14 09:40:48 2018 -0300
@@ -2602,7 +2602,7 @@
* Returns a string whose value is this string, with all leading
* and trailing space removed, where space is defined
* as any character whose codepoint is less than or equal to
- * {@code '\u005Cu0020'} (the space character).
+ * {@code 'U+0020'} (the space character).
* <p>
* If this {@code String} object represents an empty character
* sequence, or the first and last characters of character sequence
@@ -2637,6 +2637,98 @@
}
/**
+ * Returns a string whose value is this string, with all leading
+ * and trailing {@link Character#isWhitespace(int) white space}
+ * removed.
+ * <p>
+ * If this {@code String} object represents an empty string,
+ * or if all code points in this string are
+ * {@link Character#isWhitespace(int) white space}, then an empty string
+ * is returned.
+ * <p>
+ * Otherwise, returns a substring of this string beginning with the first
+ * code point that is not a {@link Character#isWhitespace(int) white space}
+ * up to and including the last code point that is not a
+ * {@link Character#isWhitespace(int) white space}.
+ * <p>
+ * This method may be used to strip
+ * {@link Character#isWhitespace(int) white space} from
+ * the beginning and end of a string.
+ *
+ * @return a string whose value is this string, with all leading
+ * and trailing white space removed
+ *
+ * @see Character#isWhitespace(int)
+ *
+ * @since 11
+ */
+ public String strip() {
+ String ret = isLatin1() ? StringLatin1.strip(value)
+ : StringUTF16.strip(value);
+ return ret == null ? this : ret;
+ }
+
+ /**
+ * Returns a string whose value is this string, with all leading
+ * {@link Character#isWhitespace(int) white space} removed.
+ * <p>
+ * If this {@code String} object represents an empty string,
+ * or if all code points in this string are
+ * {@link Character#isWhitespace(int) white space}, then an empty string
+ * is returned.
+ * <p>
+ * Otherwise, returns a substring of this string beginning with the first
+ * code point that is not a {@link Character#isWhitespace(int) white space}
+ * up to to and including the last code point of this string.
+ * <p>
+ * This method may be used to trim
+ * {@link Character#isWhitespace(int) white space} from
+ * the beginning of a string.
+ *
+ * @return a string whose value is this string, with all leading white
+ * space removed
+ *
+ * @see Character#isWhitespace(int)
+ *
+ * @since 11
+ */
+ public String stripLeading() {
+ String ret = isLatin1() ? StringLatin1.stripLeading(value)
+ : StringUTF16.stripLeading(value);
+ return ret == null ? this : ret;
+ }
+
+ /**
+ * Returns a string whose value is this string, with all trailing
+ * {@link Character#isWhitespace(int) white space} removed.
+ * <p>
+ * If this {@code String} object represents an empty string,
+ * or if all characters in this string are
+ * {@link Character#isWhitespace(int) white space}, then an empty string
+ * is returned.
+ * <p>
+ * Otherwise, returns a substring of this string beginning with the first
+ * code point of this string up to and including the last code point
+ * that is not a {@link Character#isWhitespace(int) white space}.
+ * <p>
+ * This method may be used to trim
+ * {@link Character#isWhitespace(int) white space} from
+ * the end of a string.
+ *
+ * @return a string whose value is this string, with all trailing white
+ * space removed
+ *
+ * @see Character#isWhitespace(int)
+ *
+ * @since 11
+ */
+ public String stripTrailing() {
+ String ret = isLatin1() ? StringLatin1.stripTrailing(value)
+ : StringUTF16.stripTrailing(value);
+ return ret == null ? this : ret;
+ }
+
+ /**
* This object (which is already a string!) is itself returned.
*
* @return the string itself.
--- a/src/java.base/share/classes/java/lang/StringLatin1.java Mon May 14 11:47:03 2018 +0200
+++ b/src/java.base/share/classes/java/lang/StringLatin1.java Mon May 14 09:40:48 2018 -0300
@@ -538,6 +538,57 @@
newString(value, st, len - st) : null;
}
+ public static int indexOfNonWhitespace(byte[] value) {
+ int length = value.length;
+ int left = 0;
+ while (left < length) {
+ char ch = (char)(value[left] & 0xff);
+ if (ch != ' ' && ch != '\t' && !Character.isWhitespace(ch)) {
+ break;
+ }
+ left++;
+ }
+ return left;
+ }
+
+ public static int lastIndexOfNonWhitespace(byte[] value) {
+ int length = value.length;
+ int right = length;
+ while (0 < right) {
+ char ch = (char)(value[right - 1] & 0xff);
+ if (ch != ' ' && ch != '\t' && !Character.isWhitespace(ch)) {
+ break;
+ }
+ right--;
+ }
+ return right;
+ }
+
+ public static String strip(byte[] value) {
+ int left = indexOfNonWhitespace(value);
+ if (left == value.length) {
+ return "";
+ }
+ int right = lastIndexOfNonWhitespace(value);
+ return ((left > 0) || (right < value.length)) ? newString(value, left, right - left) : null;
+ }
+
+ public static String stripLeading(byte[] value) {
+ int left = indexOfNonWhitespace(value);
+ if (left == value.length) {
+ return "";
+ }
+ return (left != 0) ? newString(value, left, value.length - left) : null;
+ }
+
+ public static String stripTrailing(byte[] value) {
+ int right = lastIndexOfNonWhitespace(value);
+ if (right == 0) {
+ return "";
+ }
+ return (right != value.length) ? newString(value, 0, right) : null;
+ }
+
public static void putChar(byte[] val, int index, int c) {
//assert (canEncode(c));
val[index] = (byte)(c);
--- a/src/java.base/share/classes/java/lang/StringUTF16.java Mon May 14 11:47:03 2018 +0200
+++ b/src/java.base/share/classes/java/lang/StringUTF16.java Mon May 14 09:40:48 2018 -0300
@@ -856,6 +856,61 @@
null;
}
+
+ public static int indexOfNonWhitespace(byte[] value) {
+ int length = value.length >> 1;
+ int left = 0;
+ while (left < length) {
+ int codepoint = codePointAt(value, left, length);
+ if (codepoint != ' ' && codepoint != '\t' && !Character.isWhitespace(codepoint)) {
+ break;
+ }
+ left += Character.charCount(codepoint);
+ }
+ return left;
+ }
+
+ public static int lastIndexOfNonWhitespace(byte[] value) {
+ int length = value.length >> 1;
+ int right = length;
+ while (0 < right) {
+ int codepoint = codePointBefore(value, right);
+ if (codepoint != ' ' && codepoint != '\t' && !Character.isWhitespace(codepoint)) {
+ break;
+ }
+ right -= Character.charCount(codepoint);
+ }
+ return right;
+ }
+
+ public static String strip(byte[] value) {
+ int length = value.length >> 1;
+ int left = indexOfNonWhitespace(value);
+ if (left == length) {
+ return "";
+ }
+ int right = lastIndexOfNonWhitespace(value);
+ return ((left > 0) || (right < length)) ? newString(value, left, right - left) : null;
+ }
+
+ public static String stripLeading(byte[] value) {
+ int length = value.length >> 1;
+ int left = indexOfNonWhitespace(value);
+ if (left == length) {
+ return "";
+ }
+ return (left != 0) ? newString(value, left, length - left) : null;
+ }
+
+ public static String stripTrailing(byte[] value) {
+ int length = value.length >> 1;
+ int right = lastIndexOfNonWhitespace(value);
+ if (right == 0) {
+ return "";
+ }
+ return (right != length) ? newString(value, 0, right) : null;
+ }
+
private static void putChars(byte[] val, int index, char[] str, int off, int end) {
while (off < end) {
putChar(val, index++, str[off++]);
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/String/Strip.java Mon May 14 09:40:48 2018 -0300
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2018, 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.
+ *
+ * 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.
+ */
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * @test
+ * @summary Basic strip, stripLeading, stripTrailing functionality
+ * @bug 8200377
+ * @run main/othervm Strip
+ */
+
+public class Strip {
+ public static void main(String... arg) {
+ testStrip();
+ testWhitespace();
+ }
+
+ /*
+ * Test basic stripping routines
+ */
+ static void testStrip() {
+ equal(" abc ".strip(), "abc");
+ equal(" abc ".stripLeading(), "abc ");
+ equal(" abc ".stripTrailing(), " abc");
+ equal(" abc\u2022 ".strip(), "abc\u2022");
+ equal(" abc\u2022 ".stripLeading(), "abc\u2022 ");
+ equal(" abc\u2022 ".stripTrailing(), " abc\u2022");
+ equal("".strip(), "");
+ equal("".stripLeading(), "");
+ equal("".stripTrailing(), "");
+ equal("\b".strip(), "\b");
+ equal("\b".stripLeading(), "\b");
+ equal("\b".stripTrailing(), "\b");
+ }
+
+ /*
+ * Test full whitespace range
+ */
+ static void testWhitespace() {
+ StringBuilder sb = new StringBuilder(64);
+ IntStream.range(1, 0xFFFF).filter(c -> Character.isWhitespace(c))
+ .forEach(c -> sb.append((char)c));
+ String whiteSpace = sb.toString();
+
+ String testString = whiteSpace + "abc" + whiteSpace;
+ equal(testString.strip(), "abc");
+ equal(testString.stripLeading(), "abc" + whiteSpace);
+ equal(testString.stripTrailing(), whiteSpace + "abc");
+ }
+
+ /*
+ * Report difference in result.
+ */
+ static void report(String message, String inputTag, String input,
+ String outputTag, String output) {
+ System.err.println(message);
+ System.err.println();
+ System.err.println(inputTag);
+ System.err.println(input.codePoints()
+ .mapToObj(c -> (Integer)c)
+ .collect(Collectors.toList()));
+ System.err.println();
+ System.err.println(outputTag);
+ System.err.println(output.codePoints()
+ .mapToObj(c -> (Integer)c)
+ .collect(Collectors.toList()));
+ throw new RuntimeException();
+ }
+
+ /*
+ * Raise an exception if the two inputs are not equivalent.
+ */
+ static void equal(String input, String expected) {
+ if (input == null || expected == null || !expected.equals(input)) {
+ report("Failed equal", "Input:", input, "Expected:", expected);
+ }
+ }
+}