1 /* 2 * Copyright (c) 2015, 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 /* 25 * @test 26 * @bug 8140450 27 * @summary Basic test for the StackWalker::walk method 28 * @run testng Basic 29 */ 30 31 import java.lang.StackWalker.StackFrame; 32 import java.util.List; 33 import java.util.stream.Collectors; 34 import static java.lang.StackWalker.Option.*; 35 36 import org.testng.annotations.DataProvider; 37 import org.testng.annotations.Test; 38 39 public class Basic { 40 private static boolean verbose = false; 41 42 @DataProvider(name = "stackDepths") 43 public static Object[][] stackDepths() { 44 return new Object[][] { 45 { new int[] { 12 }, new int[] { 4, 8, 12} }, 46 { new int[] { 18 }, new int[] { 8, 16, 20} }, 47 { new int[] { 32 }, new int[] { 16, 32, 64} }, 48 }; 49 } 50 51 /** 52 * For a stack of a given depth, it creates a StackWalker with an estimate. 53 * Test walking different number of frames 54 */ 55 @Test(dataProvider = "stackDepths") 56 public static void test(int[] depth, int[] estimates) { 57 Basic test = new Basic(depth[0]); 58 for (int estimate : estimates) { 59 test.walk(estimate); 60 } 61 } 62 63 private final int depth; 64 Basic(int depth) { 65 this.depth = depth; 66 } 67 68 /* 69 * Setup a stack builder with the expected stack depth 70 * Walk the stack and count the frames. 71 */ 72 void walk(int estimate) { 73 int limit = Math.min(depth, 16); 74 List<StackFrame> frames = new StackBuilder(depth, limit).build(); 75 System.out.format("depth=%d estimate=%d expected=%d walked=%d%n", 76 depth, estimate, limit, frames.size()); 77 assertEquals(limit, frames.size()); 78 } 79 80 class StackBuilder { 81 private final int stackDepth; 82 private final int limit; 83 private int depth = 0; 84 private List<StackFrame> result; 85 StackBuilder(int stackDepth, int limit) { 86 this.stackDepth = stackDepth; // build method; 87 this.limit = limit; 88 } 89 List<StackFrame> build() { 90 trace("build"); 91 m1(); 92 return result; 93 } 94 void m1() { 95 trace("m1"); 96 m2(); 97 } 98 void m2() { 99 trace("m2"); 100 m3(); 101 } 102 void m3() { 103 trace("m3"); 104 m4(); 105 } 106 void m4() { 107 trace("m4"); 108 int remaining = stackDepth-depth-1; 109 if (remaining >= 4) { 110 m1(); 111 } else { 112 filler(remaining); 113 } 114 } 115 void filler(int i) { 116 trace("filler"); 117 if (i == 0) 118 walk(); 119 else 120 filler(--i); 121 } 122 123 void walk() { 124 StackWalker walker = StackWalker.getInstance(RETAIN_CLASS_REFERENCE); 125 result = walker.walk(s -> s.limit(limit).collect(Collectors.toList())); 126 } 127 void trace(String methodname) { 128 ++depth; 129 if (verbose) 130 System.out.format("%2d: %s%n", depth, methodname); 131 } 132 } 133 134 static void assertEquals(int x, int y) { 135 if (x != y) { 136 throw new RuntimeException(x + " != " + y); 137 } 138 } 139 }