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src/java.base/share/classes/java/io/DeleteOnExitHook.java

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   1 /*
   2  * Copyright (c) 2005, 2018, 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 package java.io;
  26 
  27 import java.util.*;
  28 
  29 import jdk.internal.access.SharedSecrets;
  30 
  31 /**
  32  * This class holds a set of filenames to be deleted on VM exit through a shutdown hook.
  33  * A set is used both to prevent double-insertion of the same file as well as offer
  34  * quick removal.
  35  */
  36 
  37 class DeleteOnExitHook {
  38     private static LinkedHashSet<String> files = new LinkedHashSet<>();
  39     static {
  40         // DeleteOnExitHook must be the last shutdown hook to be invoked.
  41         // Application shutdown hooks may add the first file to the
  42         // delete on exit list and cause the DeleteOnExitHook to be
  43         // registered during shutdown in progress. So set the
  44         // registerShutdownInProgress parameter to true.
  45         SharedSecrets.getJavaLangAccess()
  46             .registerShutdownHook(2 /* Shutdown hook invocation order */,
  47                 true /* register even if shutdown in progress */,
  48                 new Runnable() {
  49                     public void run() {
  50                        runHooks();
  51                     }
  52                 }
  53         );
  54     }
  55 
  56     private DeleteOnExitHook() {}
  57 
  58     static synchronized void add(String file) {
  59         if(files == null) {
  60             // DeleteOnExitHook is running. Too late to add a file
  61             throw new IllegalStateException("Shutdown in progress");
  62         }
  63 
  64         files.add(file);






  65     }
  66 
  67     static void runHooks() {
  68         LinkedHashSet<String> theFiles;
  69 
  70         synchronized (DeleteOnExitHook.class) {
  71             theFiles = files;
  72             files = null;
  73         }
  74 
  75         ArrayList<String> toBeDeleted = new ArrayList<>(theFiles);
  76 
  77         // reverse the list to maintain previous jdk deletion order.
  78         // Last in first deleted.
  79         Collections.reverse(toBeDeleted);
  80         for (String filename : toBeDeleted) {
  81             (new File(filename)).delete();
  82         }
  83     }
  84 }
   1 /*
   2  * Copyright (c) 2005, 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.  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 package java.io;
  26 
  27 import java.util.*;
  28 
  29 import jdk.internal.access.SharedSecrets;
  30 
  31 /**
  32  * This class holds a set of filenames to be deleted on VM exit through a shutdown hook.
  33  * A set is used both to prevent double-insertion of the same file as well as offer
  34  * quick removal.
  35  */
  36 
  37 class DeleteOnExitHook {
  38     private static LinkedHashMap<String, int[]> files = new LinkedHashMap<>();
  39     static {
  40         // DeleteOnExitHook must be the last shutdown hook to be invoked.
  41         // Application shutdown hooks may add the first file to the
  42         // delete on exit list and cause the DeleteOnExitHook to be
  43         // registered during shutdown in progress. So set the
  44         // registerShutdownInProgress parameter to true.
  45         SharedSecrets.getJavaLangAccess()
  46             .registerShutdownHook(2 /* Shutdown hook invocation order */,
  47                 true /* register even if shutdown in progress */,
  48                 new Runnable() {
  49                     public void run() {
  50                        runHooks();
  51                     }
  52                 }
  53         );
  54     }
  55 
  56     private DeleteOnExitHook() {}
  57 
  58     static synchronized void add(String file) {
  59         if(files == null) {
  60             // DeleteOnExitHook is running. Too late to add a file
  61             throw new IllegalStateException("Shutdown in progress");
  62         }
  63 
  64         files.computeIfAbsent(file, f -> new int[1])[0]++;
  65     }
  66 
  67     static synchronized void remove(String file) {
  68         if(files != null) {
  69             files.computeIfPresent(file, (f, count) -> --count[0] <= 0 ? null : count);
  70         }
  71     }
  72 
  73     static void runHooks() {
  74         LinkedHashMap<String, int[]> theFiles;
  75 
  76         synchronized (DeleteOnExitHook.class) {
  77             theFiles = files;
  78             files = null;
  79         }
  80 
  81         ArrayList<String> toBeDeleted = new ArrayList<>(theFiles.keySet());
  82 
  83         // reverse the list to maintain previous jdk deletion order.
  84         // Last in first deleted.
  85         Collections.reverse(toBeDeleted);
  86         for (String filename : toBeDeleted) {
  87             (new File(filename)).delete();
  88         }
  89     }
  90 }
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