001 /*
002 * Copyright 2005-2008 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package com.sun.tools.javac.file;
027
028 import java.io.File;
029 import java.io.IOException;
030 import java.util.List;
031
032 import com.sun.tools.javac.util.Context;
033 import java.util.Map;
034 import java.util.concurrent.ConcurrentHashMap;
035
036 /**
037 * Caching implementation of FSInfo
038 */
039 public class CacheFSInfo extends FSInfo {
040
041 /**
042 * Register a Context.Factory to create a singleton CacheFSInfo.
043 */
044 public static void preRegister(final Context context) {
045 context.put(FSInfo.class, new Context.Factory<FSInfo>() {
046 public FSInfo make() {
047 if (singleton == null)
048 singleton = new CacheFSInfo();
049 context.put(FSInfo.class, singleton);
050 return singleton;
051 }
052 });
053 }
054
055 static CacheFSInfo singleton;
056
057 public void clearCache() {
058 cache.clear();
059 }
060
061 @Override
062 public File getCanonicalFile(File file) {
063 Entry e = getEntry(file);
064 return e.canonicalFile;
065 }
066
067 @Override
068 public boolean exists(File file) {
069 Entry e = getEntry(file);
070 return e.exists;
071 }
072
073 @Override
074 public boolean isDirectory(File file) {
075 Entry e = getEntry(file);
076 return e.isDirectory;
077 }
078
079 @Override
080 public boolean isFile(File file) {
081 Entry e = getEntry(file);
082 return e.isFile;
083 }
084
085 @Override
086 public List<File> getJarClassPath(File file) throws IOException {
087 // don't bother to lock the cache, because it is thread-safe, and
088 // because the worst that can happen would be to create two identical
089 // jar class paths together and have one overwrite the other.
090 Entry e = getEntry(file);
091 if (e.jarClassPath == null)
092 e.jarClassPath = super.getJarClassPath(file);
093 return e.jarClassPath;
094 }
095
096 private Entry getEntry(File file) {
097 // don't bother to lock the cache, because it is thread-safe, and
098 // because the worst that can happen would be to create two identical
099 // 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 }