1 /* 2 * Copyright (c) 2019, 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 package org.openjdk.bench.java.lang; 25 26 import org.openjdk.jmh.annotations.*; 27 import java.util.concurrent.TimeUnit; 28 29 @BenchmarkMode(Mode.AverageTime) 30 @OutputTimeUnit(TimeUnit.NANOSECONDS) 31 @Fork(value = 3) 32 @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS) 33 @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS) 34 @State(Scope.Benchmark) 35 public class StringSubstring { 36 37 public String s = new String("An arbitrary string that happened to be of length 52"); 38 39 @Benchmark 40 public String from26toEnd0() { 41 return s.substring(26); 42 } 43 44 @Benchmark 45 public String from26toEnd1() { 46 return s.substring(26, s.length()); 47 } 48 49 /** 50 * An empty substring should not allocate a new String 51 */ 52 @Benchmark 53 public String empty() { 54 return s.substring(17, 17); 55 } 56 }