| /* |
| * 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. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file: |
| * |
| * Written by Martin Buchholz with assistance from members of JCP |
| * JSR-166 Expert Group and released to the public domain, as |
| * explained at http://creativecommons.org/publicdomain/zero/1.0/ |
| */ |
| |
| package java.util.concurrent; |
| |
| import java.util.Collection; |
| |
| /** Shared implementation code for java.util.concurrent. */ |
| class Helpers { |
| private Helpers() {} // non-instantiable |
| |
| /** |
| * An implementation of Collection.toString() suitable for classes |
| * with locks. Instead of holding a lock for the entire duration of |
| * toString(), or acquiring a lock for each call to Iterator.next(), |
| * we hold the lock only during the call to toArray() (less |
| * disruptive to other threads accessing the collection) and follows |
| * the maxim "Never call foreign code while holding a lock". |
| */ |
| static String collectionToString(Collection<?> c) { |
| final Object[] a = c.toArray(); |
| final int size = a.length; |
| if (size == 0) |
| return "[]"; |
| int charLength = 0; |
| |
| // Replace every array element with its string representation |
| for (int i = 0; i < size; i++) { |
| Object e = a[i]; |
| // Extreme compatibility with AbstractCollection.toString() |
| String s = (e == c) ? "(this Collection)" : objectToString(e); |
| a[i] = s; |
| charLength += s.length(); |
| } |
| |
| return toString(a, size, charLength); |
| } |
| |
| /** |
| * Like Arrays.toString(), but caller guarantees that size > 0, |
| * each element with index 0 <= i < size is a non-null String, |
| * and charLength is the sum of the lengths of the input Strings. |
| */ |
| static String toString(Object[] a, int size, int charLength) { |
| // assert a != null; |
| // assert size > 0; |
| |
| // Copy each string into a perfectly sized char[] |
| // Length of [ , , , ] == 2 * size |
| final char[] chars = new char[charLength + 2 * size]; |
| chars[0] = '['; |
| int j = 1; |
| for (int i = 0; i < size; i++) { |
| if (i > 0) { |
| chars[j++] = ','; |
| chars[j++] = ' '; |
| } |
| String s = (String) a[i]; |
| int len = s.length(); |
| s.getChars(0, len, chars, j); |
| j += len; |
| } |
| chars[j] = ']'; |
| // assert j == chars.length - 1; |
| return new String(chars); |
| } |
| |
| /** Optimized form of: key + "=" + val */ |
| static String mapEntryToString(Object key, Object val) { |
| final String k, v; |
| final int klen, vlen; |
| final char[] chars = |
| new char[(klen = (k = objectToString(key)).length()) + |
| (vlen = (v = objectToString(val)).length()) + 1]; |
| k.getChars(0, klen, chars, 0); |
| chars[klen] = '='; |
| v.getChars(0, vlen, chars, klen + 1); |
| return new String(chars); |
| } |
| |
| private static String objectToString(Object x) { |
| // Extreme compatibility with StringBuilder.append(null) |
| String s; |
| return (x == null || (s = x.toString()) == null) ? "null" : s; |
| } |
| } |