2 * Copyright (C) 2001, 2002 The Mir-coders group
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4 * This file is part of Mir.
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6 * Mir is free software; you can redistribute it and/or modify
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7 * it under the terms of the GNU General Public License as published by
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8 * the Free Software Foundation; either version 2 of the License, or
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9 * (at your option) any later version.
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11 * Mir is distributed in the hope that it will be useful,
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 * GNU General Public License for more details.
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16 * You should have received a copy of the GNU General Public License
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17 * along with Mir; if not, write to the Free Software
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18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 * In addition, as a special exception, The Mir-coders gives permission to link
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21 * the code of this program with any library licensed under the Apache Software License,
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22 * The Sun (tm) Java Advanced Imaging library (JAI), The Sun JIMI library
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23 * (or with modified versions of the above that use the same license as the above),
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24 * and distribute linked combinations including the two. You must obey the
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25 * GNU General Public License in all respects for all of the code used other than
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26 * the above mentioned libraries. If you modify this file, you may extend this
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27 * exception to your version of the file, but you are not obligated to do so.
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28 * If you do not wish to do so, delete this exception statement from your version.
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30 package mir.generator.tal;
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32 import java.io.File;
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33 import java.io.FileInputStream;
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34 import java.io.FileNotFoundException;
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35 import java.io.InputStream;
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36 import java.util.HashMap;
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37 import java.util.List;
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38 import java.util.Map;
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39 import java.util.Vector;
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41 public class CachingFileLoader {
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42 private Map cachedObjects;
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43 private List history;
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44 private int capacity;
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45 private CachedFileObjectFactory factory;
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47 public CachingFileLoader(int aCapacity, CachedFileObjectFactory aFactory) {
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48 capacity = aCapacity;
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49 cachedObjects = new HashMap();
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50 history = new Vector();
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54 private void cacheObject(String aFilename, long aLastModified, Object anObject) {
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55 synchronized (this) {
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56 history.remove(aFilename);
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57 history.add(aFilename);
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58 while (history.size()>capacity && history.size()>0) {
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61 cachedObjects.put(aFilename, new CachedObject(aFilename, aLastModified, anObject));
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65 private Object constructObject(String aFilename) throws FileNotFoundException {
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66 File file = new File(aFilename);
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67 FileInputStream inputStream = new FileInputStream(file);
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69 Object result = factory.constructObject(inputStream);
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70 cacheObject(aFilename, file.lastModified(), result);
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76 inputStream.close();
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78 catch (Throwable t) {
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83 private void revatilize(String aFilename) {
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84 synchronized (this) {
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85 history.remove(aFilename);
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86 history.add(aFilename);
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90 private class CachedObject {
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91 private String filename;
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92 private long lastModified;
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93 private Object object;
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95 public CachedObject(String aFilename, long aLastModified, Object anObject) {
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96 filename = aFilename;
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97 lastModified = aLastModified;
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101 public Object getObject() {
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105 public String getFilename() {
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109 public long getLastModified() {
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110 return lastModified;
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114 public Object retrieveFile(String aFilename) throws FileNotFoundException {
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115 synchronized (this) {
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116 if (!cachedObjects.containsKey(aFilename)) {
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117 return constructObject(aFilename);
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120 CachedObject cachedObject = (CachedObject) cachedObjects.get(aFilename);
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121 File file = new File(aFilename);
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122 if (file.lastModified() != cachedObject.getLastModified()) {
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123 return constructObject(aFilename);
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126 revatilize(aFilename);
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128 return cachedObject.getObject();
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132 public interface CachedFileObjectFactory {
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133 Object constructObject(InputStream aStream);
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