1 /*

     2  * Copyright 2005-2008 Sun Microsystems, Inc.  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.  Sun designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 package com.sun.tools.javac.file;

    27 

    28 import java.io.File;

    29 import java.io.IOException;

    30 import java.util.List;

    31 

    32 import com.sun.tools.javac.util.Context;

    33 import java.util.Map;

    34 import java.util.concurrent.ConcurrentHashMap;

    35 

    36 /**

    37  * Caching implementation of FSInfo

    38  */

    39 public class CacheFSInfo extends FSInfo {

    40 

    41     /**

    42      * Register a Context.Factory to create a singleton CacheFSInfo.

    43      */

    44     public static void preRegister(final Context context) {

    45         context.put(FSInfo.class, new Context.Factory<FSInfo>() {

    46             public FSInfo make() {

    47                 if (singleton == null)

    48                     singleton = new CacheFSInfo();

    49                 context.put(FSInfo.class, singleton);

    50                 return singleton;

    51             }

    52         });

    53     }

    54 

    55     static CacheFSInfo singleton;

    56 

    57     public void clearCache() {

    58         cache.clear();

    59     }

    60 

    61     @Override

    62     public File getCanonicalFile(File file) {

    63         Entry e = getEntry(file);

    64         return e.canonicalFile;

    65     }

    66 

    67     @Override

    68     public boolean exists(File file) {

    69         Entry e = getEntry(file);

    70         return e.exists;

    71     }

    72 

    73     @Override

    74     public boolean isDirectory(File file) {

    75         Entry e = getEntry(file);

    76         return e.isDirectory;

    77     }

    78 

    79     @Override

    80     public boolean isFile(File file) {

    81         Entry e = getEntry(file);

    82         return e.isFile;

    83     }

    84 

    85     @Override

    86     public List<File> getJarClassPath(File file) throws IOException {

    87         // don't bother to lock the cache, because it is thread-safe, and

    88         // because the worst that can happen would be to create two identical

    89         // jar class paths together and have one overwrite the other.

    90         Entry e = getEntry(file);

    91         if (e.jarClassPath == null)

    92             e.jarClassPath = super.getJarClassPath(file);

    93         return e.jarClassPath;

    94     }

    95 

    96     private Entry getEntry(File file) {

    97         // don't bother to lock the cache, because it is thread-safe, and

    98         // because the worst that can happen would be to create two identical

    99         // entries together and have one overwrite the other.

   100         Entry e = cache.get(file);

   101         if (e == null) {

   102             e = new Entry();

   103             e.canonicalFile = super.getCanonicalFile(file);

   104             e.exists = super.exists(file);

   105             e.isDirectory = super.isDirectory(file);

   106             e.isFile = super.isFile(file);

   107             cache.put(file, e);

   108         }

   109         return e;

   110     }

   111 

   112     // could also be a Map<File,SoftReference<Entry>> ?

   113     private Map<File,Entry> cache = new ConcurrentHashMap<File,Entry>();

   114 

   115     private static class Entry {

   116         File canonicalFile;

   117         boolean exists;

   118         boolean isFile;

   119         boolean isDirectory;

   120         List<File> jarClassPath;

   121     }

   122 }