1 /* 2 * Copyright (c) 1997, 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 27 /* 28 * The Original Code is HAT. The Initial Developer of the 29 * Original Code is Bill Foote, with contributions from others 30 * at JavaSoft/Sun. 31 */ 32 33 package jdk.test.lib.hprof.model; 34 35 import java.io.File; 36 import java.io.FileInputStream; 37 import java.io.InputStreamReader; 38 import java.io.Reader; 39 import java.io.BufferedReader; 40 import java.io.IOException; 41 42 import java.util.Hashtable; 43 44 /** 45 * This represents a set of data members that should be excluded from the 46 * reachable objects query. 47 * This is useful to exclude observers from the 48 * transitive closure of objects reachable from a given object, allowing 49 * some kind of real determination of the "size" of that object. 50 * 51 * @author Bill Foote 52 */ 53 public class ReachableExcludesImpl implements ReachableExcludes { 54 55 private File excludesFile; 56 private long lastModified; 57 private Hashtable<String, String> methods; // Used as a bag 58 59 /** 60 * Create a new ReachableExcludesImpl over the given file. The file will be 61 * re-read whenever the timestamp changes. 62 */ 63 public ReachableExcludesImpl(File excludesFile) { 64 this.excludesFile = excludesFile; 65 readFile(); 66 } 67 68 private void readFileIfNeeded() { 69 if (excludesFile.lastModified() != lastModified) { 70 synchronized(this) { 71 if (excludesFile.lastModified() != lastModified) { 72 readFile(); 73 } 74 } 75 } 76 } 77 78 private void readFile() { 79 long lm = excludesFile.lastModified(); 80 Hashtable<String, String> m = new Hashtable<String, String>(); 81 82 try { 83 BufferedReader r = new BufferedReader(new InputStreamReader( 84 new FileInputStream(excludesFile))); 85 86 String method; 87 while ((method = r.readLine()) != null) { 88 m.put(method, method); 89 } 90 lastModified = lm; 91 methods = m; // We want this to be atomic 92 } catch (IOException ex) { 93 System.out.println("Error reading " + excludesFile + ": " + ex); 94 } 95 } 96 97 /** 98 * @return true iff the given field is on the histlist of excluded 99 * fields. 100 */ 101 public boolean isExcluded(String fieldName) { 102 readFileIfNeeded(); 103 return methods.get(fieldName) != null; 104 } 105 }