001    /*
002     * Copyright (C) 2008-2010 by Holger Arndt
003     *
004     * This file is part of the Universal Java Matrix Package (UJMP).
005     * See the NOTICE file distributed with this work for additional
006     * information regarding copyright ownership and licensing.
007     *
008     * UJMP is free software; you can redistribute it and/or modify
009     * it under the terms of the GNU Lesser General Public License as
010     * published by the Free Software Foundation; either version 2
011     * of the License, or (at your option) any later version.
012     *
013     * UJMP is distributed in the hope that it will be useful,
014     * but WITHOUT ANY WARRANTY; without even the implied warranty of
015     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
016     * GNU Lesser General Public License for more details.
017     *
018     * You should have received a copy of the GNU Lesser General Public
019     * License along with UJMP; if not, write to the
020     * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
021     * Boston, MA  02110-1301  USA
022     */
023    
024    package org.ujmp.core.collections;
025    
026    import java.io.BufferedInputStream;
027    import java.io.BufferedOutputStream;
028    import java.io.File;
029    import java.io.FileInputStream;
030    import java.io.FileOutputStream;
031    import java.io.IOException;
032    import java.io.InputStream;
033    import java.io.OutputStream;
034    import java.io.Serializable;
035    import java.util.HashSet;
036    import java.util.Set;
037    import java.util.zip.GZIPInputStream;
038    import java.util.zip.GZIPOutputStream;
039    
040    import org.ujmp.core.exceptions.MatrixException;
041    import org.ujmp.core.interfaces.Erasable;
042    import org.ujmp.core.util.SerializationUtil;
043    import org.ujmp.core.util.StringUtil;
044    import org.ujmp.core.util.io.FileUtil;
045    
046    public abstract class AbstractDiskMap<K, V> extends AbstractMap<K, V> implements Erasable {
047            private static final long serialVersionUID = -8615077389159395747L;
048    
049            private File path = null;
050    
051            private boolean useGZip = true;
052    
053            private int maxDepth = 10;
054    
055            public AbstractDiskMap(File path, boolean useGZip) throws IOException {
056                    this.useGZip = useGZip;
057                    this.path = path;
058            }
059    
060            public final File getPath() {
061                    if (path == null) {
062                            try {
063                                    path = File.createTempFile("diskmap" + System.nanoTime(), "");
064                                    path.delete();
065                                    if (!path.exists()) {
066                                            path.mkdirs();
067                                    }
068                            } catch (Exception e) {
069                                    throw new MatrixException(e);
070                            }
071                    }
072                    return path;
073            }
074    
075            public synchronized final int size() {
076                    return FileUtil.countFiles(getPath());
077            }
078    
079            private final File getFileNameForKey(Object o) throws IOException {
080                    String key;
081                    String suffix = ".dat";
082                    if (useGZip) {
083                            suffix += ".gz";
084                    }
085                    if (o instanceof String && StringUtil.isSuitedAsFilename((String) o)
086                                    && !((String) o).contains(".")) {
087                            key = (String) o;
088                    } else {
089                            suffix = ".obj" + suffix;
090                            key = StringUtil.reverse(StringUtil.encodeToHex((Serializable) o));
091                    }
092                    StringBuilder result = new StringBuilder();
093                    result.append(getPath().getAbsolutePath());
094                    result.append(File.separator);
095                    for (int i = 0; i < maxDepth && i < key.length() - 1; i++) {
096                            char c = key.charAt(i);
097                            result.append(c);
098                            result.append(File.separator);
099                    }
100                    result.append(key);
101                    result.append(suffix);
102                    return new File(result.toString());
103            }
104    
105            public synchronized final V remove(Object key) {
106                    try {
107                            V v = get(key);
108                            File file = getFileNameForKey(key);
109                            if (file.exists()) {
110                                    file.delete();
111                            }
112                            return v;
113                    } catch (Exception e) {
114                            throw new RuntimeException(e);
115                    }
116            }
117    
118            public synchronized final boolean containsKey(Object key) {
119                    try {
120                            File file = getFileNameForKey(key);
121                            if (file == null) {
122                                    return false;
123                            }
124                            return file.exists();
125                    } catch (Exception e) {
126                            throw new RuntimeException(e);
127                    }
128            }
129    
130            // TODO: better with an Iterator
131            public final Set<K> keySet() {
132                    try {
133                            Set<K> set = new HashSet<K>();
134                            listFilesToSet(getPath(), set);
135                            return set;
136                    } catch (Exception e) {
137                            throw new RuntimeException(e);
138                    }
139            }
140    
141            private void listFilesToSet(File path, Set<K> set) throws ClassNotFoundException, IOException {
142                    File[] files = path.listFiles();
143                    if (files != null) {
144                            for (File f : files) {
145                                    if (f.isDirectory()) {
146                                            listFilesToSet(f, set);
147                                    } else {
148                                            set.add(getKeyForFile(f));
149                                    }
150                            }
151                    }
152            }
153    
154            @SuppressWarnings("unchecked")
155            private K getKeyForFile(File file) throws ClassNotFoundException, IOException {
156                    String filename = file.getName();
157                    if (filename.endsWith(".gz")) {
158                            filename = filename.substring(0, filename.length() - 3);
159                    }
160                    if (filename.endsWith(".dat")) {
161                            filename = filename.substring(0, filename.length() - 4);
162                    }
163                    if (filename.endsWith(".obj")) {
164                            filename = filename.substring(0, filename.length() - 4);
165                            filename = StringUtil.reverse(filename);
166                            return (K) SerializationUtil.deserialize(StringUtil.decodeFromHex(filename));
167                    } else {
168                            return (K) filename;
169                    }
170            }
171    
172            public final synchronized void clear() {
173                    try {
174                            erase();
175                    } catch (Exception e) {
176                            e.printStackTrace();
177                    }
178            }
179    
180            public final void erase() throws IOException {
181                    FileUtil.deleteRecursive(path);
182            }
183    
184            public final void setPath(File path) {
185                    this.path = path;
186            }
187    
188            public final synchronized V put(K key, V value) {
189                    try {
190                            if (key == null) {
191                                    return null;
192                            }
193    
194                            File file = getFileNameForKey(key);
195    
196                            if (value == null && file.exists()) {
197                                    file.delete();
198                                    return null;
199                            }
200    
201                            if (!file.getParentFile().exists()) {
202                                    file.getParentFile().mkdirs();
203                            }
204    
205                            FileOutputStream fo = new FileOutputStream(file);
206    
207                            OutputStream bo = new BufferedOutputStream(fo);
208                            if (useGZip) {
209                                    bo = new GZIPOutputStream(bo, 8192);
210                            }
211    
212                            writeValue(bo, value);
213    
214                            bo.close();
215                            fo.close();
216    
217                            return null;
218                    } catch (Exception e) {
219                            throw new MatrixException("could not put object " + key, e);
220                    }
221            }
222    
223            public final synchronized V get(Object key) {
224                    try {
225                            File file = getFileNameForKey(key);
226                            if (file == null || !file.exists()) {
227                                    return null;
228                            }
229    
230                            V o = null;
231    
232                            FileInputStream fi = new FileInputStream(file);
233                            InputStream bi = new BufferedInputStream(fi);
234                            if (useGZip) {
235                                    bi = new GZIPInputStream(bi, 8192);
236                            }
237    
238                            o = readValue(bi);
239    
240                            bi.close();
241                            fi.close();
242    
243                            return o;
244                    } catch (Exception e) {
245                            throw new MatrixException("could not get object " + key, e);
246                    }
247            }
248    
249            public abstract void writeValue(OutputStream os, V value);
250    
251            public abstract V readValue(InputStream is);
252    
253    }