1 | // License: GPL. For details, see LICENSE file.
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2 | package org.openstreetmap.josm.data.cache;
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3 |
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4 | import java.io.FileNotFoundException;
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5 | import java.io.IOException;
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6 | import java.net.HttpURLConnection;
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7 | import java.net.URL;
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8 | import java.security.SecureRandom;
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9 | import java.util.HashSet;
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10 | import java.util.List;
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11 | import java.util.Map;
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12 | import java.util.Set;
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13 | import java.util.concurrent.ConcurrentHashMap;
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14 | import java.util.concurrent.ConcurrentMap;
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15 | import java.util.concurrent.LinkedBlockingDeque;
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16 | import java.util.concurrent.ThreadPoolExecutor;
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17 | import java.util.concurrent.TimeUnit;
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18 | import java.util.regex.Matcher;
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19 |
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20 | import org.apache.commons.jcs.access.behavior.ICacheAccess;
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21 | import org.apache.commons.jcs.engine.behavior.ICacheElement;
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22 | import org.openstreetmap.josm.data.cache.ICachedLoaderListener.LoadResult;
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23 | import org.openstreetmap.josm.data.preferences.IntegerProperty;
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24 | import org.openstreetmap.josm.tools.CheckParameterUtil;
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25 | import org.openstreetmap.josm.tools.HttpClient;
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26 | import org.openstreetmap.josm.tools.Logging;
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27 | import org.openstreetmap.josm.tools.Utils;
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28 |
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29 | /**
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30 | * Generic loader for HTTP based tiles. Uses custom attribute, to check, if entry has expired
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31 | * according to HTTP headers sent with tile. If so, it tries to verify using Etags
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32 | * or If-Modified-Since / Last-Modified.
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33 | *
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34 | * If the tile is not valid, it will try to download it from remote service and put it
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35 | * to cache. If remote server will fail it will try to use stale entry.
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36 | *
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37 | * This class will keep only one Job running for specified tile. All others will just finish, but
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38 | * listeners will be gathered and notified, once download job will be finished
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39 | *
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40 | * @author Wiktor Niesiobędzki
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41 | * @param <K> cache entry key type
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42 | * @param <V> cache value type
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43 | * @since 8168
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44 | */
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45 | public abstract class JCSCachedTileLoaderJob<K, V extends CacheEntry> implements ICachedLoaderJob<K> {
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46 | protected static final long DEFAULT_EXPIRE_TIME = TimeUnit.DAYS.toMillis(7);
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47 | // Limit for the max-age value send by the server.
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48 | protected static final long EXPIRE_TIME_SERVER_LIMIT = TimeUnit.DAYS.toMillis(28);
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49 | // Absolute expire time limit. Cached tiles that are older will not be used,
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50 | // even if the refresh from the server fails.
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51 | protected static final long ABSOLUTE_EXPIRE_TIME_LIMIT = TimeUnit.DAYS.toMillis(365);
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52 |
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53 | /**
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54 | * maximum download threads that will be started
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55 | */
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56 | public static final IntegerProperty THREAD_LIMIT = new IntegerProperty("cache.jcs.max_threads", 10);
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57 |
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58 | /*
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59 | * ThreadPoolExecutor starts new threads, until THREAD_LIMIT is reached. Then it puts tasks into LinkedBlockingDeque.
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60 | *
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61 | * The queue works FIFO, so one needs to take care about ordering of the entries submitted
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62 | *
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63 | * There is no point in canceling tasks, that are already taken by worker threads (if we made so much effort, we can at least cache
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64 | * the response, so later it could be used). We could actually cancel what is in LIFOQueue, but this is a tradeoff between simplicity
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65 | * and performance (we do want to have something to offer to worker threads before tasks will be resubmitted by class consumer)
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66 | */
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67 |
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68 | private static final ThreadPoolExecutor DEFAULT_DOWNLOAD_JOB_DISPATCHER = new ThreadPoolExecutor(
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69 | 1, // we have a small queue, so threads will be quickly started (threads are started only, when queue is full)
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70 | THREAD_LIMIT.get(), // do not this number of threads
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71 | 30, // keepalive for thread
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72 | TimeUnit.SECONDS,
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73 | // make queue of LIFO type - so recently requested tiles will be loaded first (assuming that these are which user is waiting to see)
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74 | new LinkedBlockingDeque<Runnable>(),
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75 | Utils.newThreadFactory("JCS-downloader-%d", Thread.NORM_PRIORITY)
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76 | );
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77 |
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78 | private static final ConcurrentMap<String, Set<ICachedLoaderListener>> inProgress = new ConcurrentHashMap<>();
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79 | private static final ConcurrentMap<String, Boolean> useHead = new ConcurrentHashMap<>();
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80 |
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81 | protected final long now; // when the job started
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82 |
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83 | private final ICacheAccess<K, V> cache;
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84 | private ICacheElement<K, V> cacheElement;
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85 | protected V cacheData;
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86 | protected CacheEntryAttributes attributes;
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87 |
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88 | // HTTP connection parameters
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89 | private final int connectTimeout;
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90 | private final int readTimeout;
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91 | private final Map<String, String> headers;
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92 | private final ThreadPoolExecutor downloadJobExecutor;
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93 | private Runnable finishTask;
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94 | private boolean force;
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95 |
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96 | /**
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97 | * @param cache cache instance that we will work on
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98 | * @param headers HTTP headers to be sent together with request
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99 | * @param readTimeout when connecting to remote resource
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100 | * @param connectTimeout when connecting to remote resource
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101 | * @param downloadJobExecutor that will be executing the jobs
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102 | */
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103 | public JCSCachedTileLoaderJob(ICacheAccess<K, V> cache,
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104 | int connectTimeout, int readTimeout,
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105 | Map<String, String> headers,
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106 | ThreadPoolExecutor downloadJobExecutor) {
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107 | CheckParameterUtil.ensureParameterNotNull(cache, "cache");
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108 | this.cache = cache;
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109 | this.now = System.currentTimeMillis();
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110 | this.connectTimeout = connectTimeout;
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111 | this.readTimeout = readTimeout;
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112 | this.headers = headers;
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113 | this.downloadJobExecutor = downloadJobExecutor;
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114 | }
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115 |
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116 | /**
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117 | * @param cache cache instance that we will work on
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118 | * @param headers HTTP headers to be sent together with request
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119 | * @param readTimeout when connecting to remote resource
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120 | * @param connectTimeout when connecting to remote resource
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121 | */
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122 | public JCSCachedTileLoaderJob(ICacheAccess<K, V> cache,
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123 | int connectTimeout, int readTimeout,
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124 | Map<String, String> headers) {
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125 | this(cache, connectTimeout, readTimeout,
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126 | headers, DEFAULT_DOWNLOAD_JOB_DISPATCHER);
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127 | }
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128 |
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129 | private void ensureCacheElement() {
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130 | if (cacheElement == null && getCacheKey() != null) {
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131 | cacheElement = cache.getCacheElement(getCacheKey());
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132 | if (cacheElement != null) {
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133 | attributes = (CacheEntryAttributes) cacheElement.getElementAttributes();
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134 | cacheData = cacheElement.getVal();
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135 | }
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136 | }
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137 | }
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138 |
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139 | @Override
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140 | public V get() {
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141 | ensureCacheElement();
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142 | return cacheData;
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143 | }
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144 |
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145 | @Override
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146 | public void submit(ICachedLoaderListener listener, boolean force) throws IOException {
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147 | this.force = force;
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148 | boolean first = false;
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149 | URL url = getUrl();
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150 | String deduplicationKey = null;
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151 | if (url != null) {
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152 | // url might be null, for example when Bing Attribution is not loaded yet
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153 | deduplicationKey = url.toString();
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154 | }
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155 | if (deduplicationKey == null) {
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156 | Logging.warn("No url returned for: {0}, skipping", getCacheKey());
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157 | throw new IllegalArgumentException("No url returned");
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158 | }
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159 | synchronized (inProgress) {
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160 | Set<ICachedLoaderListener> newListeners = inProgress.get(deduplicationKey);
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161 | if (newListeners == null) {
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162 | newListeners = new HashSet<>();
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163 | inProgress.put(deduplicationKey, newListeners);
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164 | first = true;
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165 | }
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166 | newListeners.add(listener);
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167 | }
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168 |
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169 | if (first || force) {
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170 | // submit all jobs to separate thread, so calling thread is not blocked with IO when loading from disk
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171 | Logging.debug("JCS - Submitting job for execution for url: {0}", getUrlNoException());
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172 | downloadJobExecutor.execute(this);
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173 | }
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174 | }
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175 |
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176 | /**
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177 | * This method is run when job has finished
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178 | */
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179 | protected void executionFinished() {
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180 | if (finishTask != null) {
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181 | finishTask.run();
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182 | }
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183 | }
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184 |
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185 | /**
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186 | *
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187 | * @return checks if object from cache has sufficient data to be returned
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188 | */
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189 | protected boolean isObjectLoadable() {
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190 | if (cacheData == null) {
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191 | return false;
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192 | }
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193 | return cacheData.getContent().length > 0;
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194 | }
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195 |
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196 | /**
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197 | * Simple implementation. All errors should be cached as empty. Though some JDK (JDK8 on Windows for example)
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198 | * doesn't return 4xx error codes, instead they do throw an FileNotFoundException or IOException
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199 | *
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200 | * @return true if we should put empty object into cache, regardless of what remote resource has returned
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201 | */
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202 | protected boolean cacheAsEmpty() {
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203 | return attributes.getResponseCode() < 500;
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204 | }
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205 |
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206 | /**
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207 | * @return key under which discovered server settings will be kept
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208 | */
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209 | protected String getServerKey() {
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210 | try {
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211 | return getUrl().getHost();
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212 | } catch (IOException e) {
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213 | Logging.trace(e);
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214 | return null;
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215 | }
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216 | }
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217 |
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218 | @Override
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219 | public void run() {
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220 | final Thread currentThread = Thread.currentThread();
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221 | final String oldName = currentThread.getName();
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222 | currentThread.setName("JCS Downloading: " + getUrlNoException());
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223 | Logging.debug("JCS - starting fetch of url: {0} ", getUrlNoException());
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224 | ensureCacheElement();
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225 | try {
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226 | // try to fetch from cache
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227 | if (!force && cacheElement != null && isCacheElementValid() && isObjectLoadable()) {
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228 | // we got something in cache, and it's valid, so lets return it
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229 | Logging.debug("JCS - Returning object from cache: {0}", getCacheKey());
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230 | finishLoading(LoadResult.SUCCESS);
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231 | return;
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232 | }
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233 |
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234 | // try to load object from remote resource
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235 | if (loadObject()) {
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236 | finishLoading(LoadResult.SUCCESS);
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237 | } else {
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238 | // if loading failed - check if we can return stale entry
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239 | if (isObjectLoadable()) {
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240 | // try to get stale entry in cache
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241 | finishLoading(LoadResult.SUCCESS);
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242 | Logging.debug("JCS - found stale object in cache: {0}", getUrlNoException());
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243 | } else {
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244 | // failed completely
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245 | finishLoading(LoadResult.FAILURE);
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246 | }
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247 | }
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248 | } finally {
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249 | executionFinished();
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250 | currentThread.setName(oldName);
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251 | }
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252 | }
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253 |
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254 | private void finishLoading(LoadResult result) {
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255 | Set<ICachedLoaderListener> listeners;
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256 | synchronized (inProgress) {
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257 | try {
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258 | listeners = inProgress.remove(getUrl().toString());
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259 | } catch (IOException e) {
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260 | listeners = null;
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261 | Logging.trace(e);
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262 | }
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263 | }
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264 | if (listeners == null) {
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265 | Logging.warn("Listener not found for URL: {0}. Listener not notified!", getUrlNoException());
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266 | return;
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267 | }
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268 | for (ICachedLoaderListener l: listeners) {
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269 | l.loadingFinished(cacheData, attributes, result);
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270 | }
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271 | }
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272 |
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273 | protected boolean isCacheElementValid() {
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274 | long expires = attributes.getExpirationTime();
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275 |
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276 | // check by expire date set by server
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277 | if (expires != 0L) {
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278 | // put a limit to the expire time (some servers send a value
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279 | // that is too large)
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280 | expires = Math.min(expires, attributes.getCreateTime() + EXPIRE_TIME_SERVER_LIMIT);
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281 | if (now > expires) {
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282 | Logging.debug("JCS - Object {0} has expired -> valid to {1}, now is: {2}",
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283 | new Object[]{getUrlNoException(), Long.toString(expires), Long.toString(now)});
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284 | return false;
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285 | }
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286 | } else if (attributes.getLastModification() > 0 &&
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287 | now - attributes.getLastModification() > DEFAULT_EXPIRE_TIME) {
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288 | // check by file modification date
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289 | Logging.debug("JCS - Object has expired, maximum file age reached {0}", getUrlNoException());
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290 | return false;
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291 | } else if (now - attributes.getCreateTime() > DEFAULT_EXPIRE_TIME) {
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292 | Logging.debug("JCS - Object has expired, maximum time since object creation reached {0}", getUrlNoException());
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293 | return false;
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294 | }
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295 | return true;
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296 | }
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297 |
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298 | /**
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299 | * @return true if object was successfully downloaded, false, if there was a loading failure
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300 | */
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301 | private boolean loadObject() {
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302 | if (attributes == null) {
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303 | attributes = new CacheEntryAttributes();
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304 | }
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305 | try {
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306 | // if we have object in cache, and host doesn't support If-Modified-Since nor If-None-Match
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307 | // then just use HEAD request and check returned values
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308 | if (isObjectLoadable() &&
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309 | Boolean.TRUE.equals(useHead.get(getServerKey())) &&
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310 | isCacheValidUsingHead()) {
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311 | Logging.debug("JCS - cache entry verified using HEAD request: {0}", getUrl());
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312 | return true;
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313 | }
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314 |
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315 | Logging.debug("JCS - starting HttpClient GET request for URL: {0}", getUrl());
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316 | final HttpClient request = getRequest("GET", true);
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317 |
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318 | if (isObjectLoadable() &&
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319 | (now - attributes.getLastModification()) <= ABSOLUTE_EXPIRE_TIME_LIMIT) {
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320 | request.setIfModifiedSince(attributes.getLastModification());
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321 | }
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322 | if (isObjectLoadable() && attributes.getEtag() != null) {
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323 | request.setHeader("If-None-Match", attributes.getEtag());
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324 | }
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325 |
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326 | final HttpClient.Response urlConn = request.connect();
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327 |
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328 | if (urlConn.getResponseCode() == 304) {
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329 | // If isModifiedSince or If-None-Match has been set
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330 | // and the server answers with a HTTP 304 = "Not Modified"
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331 | Logging.debug("JCS - If-Modified-Since/ETag test: local version is up to date: {0}", getUrl());
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332 | return true;
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333 | } else if (isObjectLoadable() // we have an object in cache, but we haven't received 304 response code
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334 | && (
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335 | (attributes.getEtag() != null && attributes.getEtag().equals(urlConn.getHeaderField("ETag"))) ||
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336 | attributes.getLastModification() == urlConn.getLastModified())
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337 | ) {
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338 | // we sent ETag or If-Modified-Since, but didn't get 304 response code
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339 | // for further requests - use HEAD
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340 | String serverKey = getServerKey();
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341 | Logging.info("JCS - Host: {0} found not to return 304 codes for If-Modified-Since or If-None-Match headers",
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342 | serverKey);
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343 | useHead.put(serverKey, Boolean.TRUE);
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344 | }
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345 |
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346 | attributes = parseHeaders(urlConn);
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347 |
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348 | for (int i = 0; i < 5; ++i) {
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349 | if (urlConn.getResponseCode() == HttpURLConnection.HTTP_UNAVAILABLE) {
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350 | Thread.sleep(5000L+new SecureRandom().nextInt(5000));
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351 | continue;
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352 | }
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353 |
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354 | attributes.setResponseCode(urlConn.getResponseCode());
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355 | byte[] raw;
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356 | if (urlConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
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357 | raw = Utils.readBytesFromStream(urlConn.getContent());
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358 | } else {
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359 | raw = new byte[]{};
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360 | try {
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361 | String data = urlConn.fetchContent();
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362 | if (!data.isEmpty()) {
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363 | Matcher m = HttpClient.getTomcatErrorMatcher(data);
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364 | if (m.matches()) {
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365 | attributes.setErrorMessage(m.group(1).replace("'", "''"));
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366 | }
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367 | }
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368 | } catch (IOException e) {
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369 | Logging.warn(e);
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370 | }
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371 | }
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372 |
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373 | if (isResponseLoadable(urlConn.getHeaderFields(), urlConn.getResponseCode(), raw)) {
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374 | // we need to check cacheEmpty, so for cases, when data is returned, but we want to store
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375 | // as empty (eg. empty tile images) to save some space
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376 | cacheData = createCacheEntry(raw);
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377 | cache.put(getCacheKey(), cacheData, attributes);
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378 | Logging.debug("JCS - downloaded key: {0}, length: {1}, url: {2}",
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379 | new Object[] {getCacheKey(), raw.length, getUrl()});
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380 | return true;
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381 | } else if (cacheAsEmpty()) {
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382 | cacheData = createCacheEntry(new byte[]{});
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383 | cache.put(getCacheKey(), cacheData, attributes);
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384 | Logging.debug("JCS - Caching empty object {0}", getUrl());
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385 | return true;
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386 | } else {
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387 | Logging.debug("JCS - failure during load - reponse is not loadable nor cached as empty");
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388 | return false;
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389 | }
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390 | }
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391 | } catch (FileNotFoundException e) {
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392 | Logging.debug("JCS - Caching empty object as server returned 404 for: {0}", getUrlNoException());
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393 | attributes.setResponseCode(404);
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394 | attributes.setError(e);
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395 | boolean doCache = isResponseLoadable(null, 404, null) || cacheAsEmpty();
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396 | if (doCache) {
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397 | cacheData = createCacheEntry(new byte[]{});
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398 | cache.put(getCacheKey(), cacheData, attributes);
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399 | }
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400 | return doCache;
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401 | } catch (IOException e) {
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402 | Logging.debug("JCS - IOException during communication with server for: {0}", getUrlNoException());
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403 | if (isObjectLoadable()) {
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404 | return true;
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405 | } else {
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406 | attributes.setError(e);
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407 | attributes.setResponseCode(599); // set dummy error code, greater than 500 so it will be not cached
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408 | return false;
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409 | }
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410 |
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411 | } catch (InterruptedException e) {
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412 | attributes.setError(e);
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413 | Logging.logWithStackTrace(Logging.LEVEL_WARN, e, "JCS - Exception during download {0}", getUrlNoException());
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414 | Thread.currentThread().interrupt();
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415 | }
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416 | Logging.warn("JCS - Silent failure during download: {0}", getUrlNoException());
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417 | return false;
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418 | }
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419 |
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420 | /**
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421 | * Check if the object is loadable. This means, if the data will be parsed, and if this response
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422 | * will finish as successful retrieve.
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423 | *
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424 | * This simple implementation doesn't load empty response, nor client (4xx) and server (5xx) errors
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425 | *
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426 | * @param headerFields headers sent by server
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427 | * @param responseCode http status code
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428 | * @param raw data read from server
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429 | * @return true if object should be cached and returned to listener
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430 | */
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431 | protected boolean isResponseLoadable(Map<String, List<String>> headerFields, int responseCode, byte[] raw) {
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432 | return raw != null && raw.length != 0 && responseCode < 400;
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433 | }
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434 |
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435 | protected abstract V createCacheEntry(byte[] content);
|
---|
436 |
|
---|
437 | protected CacheEntryAttributes parseHeaders(HttpClient.Response urlConn) {
|
---|
438 | CacheEntryAttributes ret = new CacheEntryAttributes();
|
---|
439 |
|
---|
440 | Long lng = urlConn.getExpiration();
|
---|
441 | if (lng.equals(0L)) {
|
---|
442 | try {
|
---|
443 | String str = urlConn.getHeaderField("Cache-Control");
|
---|
444 | if (str != null) {
|
---|
445 | for (String token: str.split(",")) {
|
---|
446 | if (token.startsWith("max-age=")) {
|
---|
447 | lng = TimeUnit.SECONDS.toMillis(Long.parseLong(token.substring(8))) + System.currentTimeMillis();
|
---|
448 | }
|
---|
449 | }
|
---|
450 | }
|
---|
451 | } catch (NumberFormatException e) {
|
---|
452 | // ignore malformed Cache-Control headers
|
---|
453 | Logging.trace(e);
|
---|
454 | }
|
---|
455 | }
|
---|
456 |
|
---|
457 | ret.setExpirationTime(lng);
|
---|
458 | ret.setLastModification(now);
|
---|
459 | ret.setEtag(urlConn.getHeaderField("ETag"));
|
---|
460 |
|
---|
461 | return ret;
|
---|
462 | }
|
---|
463 |
|
---|
464 | private HttpClient getRequest(String requestMethod, boolean noCache) throws IOException {
|
---|
465 | final HttpClient urlConn = HttpClient.create(getUrl(), requestMethod);
|
---|
466 | urlConn.setAccept("text/html, image/png, image/jpeg, image/gif, */*");
|
---|
467 | urlConn.setReadTimeout(readTimeout); // 30 seconds read timeout
|
---|
468 | urlConn.setConnectTimeout(connectTimeout);
|
---|
469 | if (headers != null) {
|
---|
470 | urlConn.setHeaders(headers);
|
---|
471 | }
|
---|
472 |
|
---|
473 | if (force || noCache) {
|
---|
474 | urlConn.useCache(false);
|
---|
475 | }
|
---|
476 | return urlConn;
|
---|
477 | }
|
---|
478 |
|
---|
479 | private boolean isCacheValidUsingHead() throws IOException {
|
---|
480 | final HttpClient.Response urlConn = getRequest("HEAD", false).connect();
|
---|
481 | long lastModified = urlConn.getLastModified();
|
---|
482 | return (attributes.getEtag() != null && attributes.getEtag().equals(urlConn.getHeaderField("ETag"))) ||
|
---|
483 | (lastModified != 0 && lastModified <= attributes.getLastModification());
|
---|
484 | }
|
---|
485 |
|
---|
486 | /**
|
---|
487 | * TODO: move to JobFactory
|
---|
488 | * cancels all outstanding tasks in the queue.
|
---|
489 | */
|
---|
490 | public void cancelOutstandingTasks() {
|
---|
491 | for (Runnable r: downloadJobExecutor.getQueue()) {
|
---|
492 | if (downloadJobExecutor.remove(r) && r instanceof JCSCachedTileLoaderJob) {
|
---|
493 | ((JCSCachedTileLoaderJob<?, ?>) r).handleJobCancellation();
|
---|
494 | }
|
---|
495 | }
|
---|
496 | }
|
---|
497 |
|
---|
498 | /**
|
---|
499 | * Sets a job, that will be run, when job will finish execution
|
---|
500 | * @param runnable that will be executed
|
---|
501 | */
|
---|
502 | public void setFinishedTask(Runnable runnable) {
|
---|
503 | this.finishTask = runnable;
|
---|
504 |
|
---|
505 | }
|
---|
506 |
|
---|
507 | /**
|
---|
508 | * Marks this job as canceled
|
---|
509 | */
|
---|
510 | public void handleJobCancellation() {
|
---|
511 | finishLoading(LoadResult.CANCELED);
|
---|
512 | }
|
---|
513 |
|
---|
514 | private URL getUrlNoException() {
|
---|
515 | try {
|
---|
516 | return getUrl();
|
---|
517 | } catch (IOException e) {
|
---|
518 | return null;
|
---|
519 | }
|
---|
520 | }
|
---|
521 | }
|
---|