1 /* 2 * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 import java.nio.CharBuffer; 25 import java.util.Iterator; 26 import java.util.Set; 27 import java.util.TreeSet; 28 import org.testng.Assert; 29 import org.testng.annotations.Test; 30 31 /** 32 * @test 33 * @bug 8215401 34 * @summary Test to verify the isEmpty method is behaviorally consistent 35 * with length 36 * @run testng Emptiness 37 */ 38 public class Emptiness { 39 40 @Test 41 public void isEmpty() { 42 checkEmpty(new StringBuilder()); 43 checkEmpty(new StringBuffer()); 44 checkEmpty(""); 45 checkEmpty(new CharSequence() { 46 @Override public int length() { return 0; } 47 @Override public char charAt(int index) { return 'f'; } 48 @Override public CharSequence subSequence(int start, int end) { 49 throw new UnsupportedOperationException(); 50 } 51 }); 52 } 53 54 @Test 55 public void isNotEmpty() { 56 checkNotEmpty(new StringBuilder().append("foo")); 57 checkNotEmpty(new StringBuffer().append("bar")); 58 checkNotEmpty("baz"); 59 checkNotEmpty(new CharSequence() { 60 @Override public int length() { return 1; } 61 @Override public char charAt(int index) { return 'f'; } 62 @Override public CharSequence subSequence(int start, int end) { 63 throw new UnsupportedOperationException(); 64 } 65 }); 66 } 67 68 public void checkEmpty(CharSequence cs) { 69 Assert.assertTrue(cs.isEmpty()); 70 Assert.assertTrue(consistentWithLength(cs)); 71 } 72 73 public void checkNotEmpty(CharSequence cs) { 74 Assert.assertTrue(!cs.isEmpty()); 75 Assert.assertTrue(consistentWithLength(cs)); 76 } 77 78 public boolean consistentWithLength(CharSequence cs) { 79 return cs.isEmpty() == (cs.length() == 0); 80 } 81 }