1 /*

     2  * Copyright (c) 1997, 2014, 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 com.sun.tools.hat.internal.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 }