001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.io;
003
004import static org.openstreetmap.josm.tools.I18n.tr;
005import static org.openstreetmap.josm.tools.I18n.trn;
006
007import java.io.InputStream;
008import java.net.HttpURLConnection;
009import java.util.ArrayList;
010import java.util.Collection;
011import java.util.HashSet;
012import java.util.Iterator;
013import java.util.LinkedHashSet;
014import java.util.List;
015import java.util.NoSuchElementException;
016import java.util.Set;
017import java.util.concurrent.Callable;
018import java.util.concurrent.CompletionService;
019import java.util.concurrent.ExecutionException;
020import java.util.concurrent.Executor;
021import java.util.concurrent.ExecutorCompletionService;
022import java.util.concurrent.Executors;
023import java.util.concurrent.Future;
024
025import org.openstreetmap.josm.Main;
026import org.openstreetmap.josm.data.osm.DataSet;
027import org.openstreetmap.josm.data.osm.DataSetMerger;
028import org.openstreetmap.josm.data.osm.Node;
029import org.openstreetmap.josm.data.osm.OsmPrimitive;
030import org.openstreetmap.josm.data.osm.OsmPrimitiveType;
031import org.openstreetmap.josm.data.osm.PrimitiveId;
032import org.openstreetmap.josm.data.osm.Relation;
033import org.openstreetmap.josm.data.osm.RelationMember;
034import org.openstreetmap.josm.data.osm.SimplePrimitiveId;
035import org.openstreetmap.josm.data.osm.Way;
036import org.openstreetmap.josm.gui.progress.NullProgressMonitor;
037import org.openstreetmap.josm.gui.progress.ProgressMonitor;
038import org.openstreetmap.josm.tools.CheckParameterUtil;
039
040/**
041 * Retrieves a set of {@link OsmPrimitive}s from an OSM server using the so called
042 * Multi Fetch API.
043 *
044 * Usage:
045 * <pre>
046 *    MultiFetchServerObjectReader reader = MultiFetchServerObjectReader()
047 *         .append(2345,2334,4444)
048 *         .append(new Node(72343));
049 *    reader.parseOsm();
050 *    if (!reader.getMissingPrimitives().isEmpty()) {
051 *        Main.info("There are missing primitives: " + reader.getMissingPrimitives());
052 *    }
053 *    if (!reader.getSkippedWays().isEmpty()) {
054 *       Main.info("There are skipped ways: " + reader.getMissingPrimitives());
055 *    }
056 * </pre>
057 */
058public class MultiFetchServerObjectReader extends OsmServerReader{
059    /**
060     * the max. number of primitives retrieved in one step. Assuming IDs with 7 digits,
061     * this leads to a max. request URL of ~ 1600 Bytes ((7 digits +  1 Separator) * 200),
062     * which should be safe according to the
063     * <a href="http://www.boutell.com/newfaq/misc/urllength.html">WWW FAQ</a>.
064     */
065    static private int MAX_IDS_PER_REQUEST = 200;
066
067    private Set<Long> nodes;
068    private Set<Long> ways;
069    private Set<Long> relations;
070    private Set<PrimitiveId> missingPrimitives;
071    private DataSet outputDataSet;
072
073    /**
074     * Constructs a {@code MultiFetchServerObjectReader}.
075     */
076    public MultiFetchServerObjectReader() {
077        nodes = new LinkedHashSet<Long>();
078        ways = new LinkedHashSet<Long>();
079        relations = new LinkedHashSet<Long>();
080        this.outputDataSet = new DataSet();
081        this.missingPrimitives = new LinkedHashSet<PrimitiveId>();
082    }
083
084    /**
085     * Remembers an {@link OsmPrimitive}'s id. The id will
086     * later be fetched as part of a Multi Get request.
087     *
088     * Ignore the id if it represents a new primitives.
089     *
090     * @param id  the id
091     */
092    protected void remember(PrimitiveId id) {
093        if (id.isNew()) return;
094        switch(id.getType()) {
095        case NODE: nodes.add(id.getUniqueId()); break;
096        case WAY: ways.add(id.getUniqueId()); break;
097        case RELATION: relations.add(id.getUniqueId()); break;
098        }
099    }
100
101    /**
102     * remembers an {@link OsmPrimitive}'s id. <code>ds</code> must include
103     * an {@link OsmPrimitive} with id=<code>id</code>. The id will
104     * later we fetched as part of a Multi Get request.
105     *
106     * Ignore the id if it id <= 0.
107     *
108     * @param ds  the dataset (must not be null)
109     * @param id  the primitive id
110     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
111     * @throws IllegalArgumentException if ds is null
112     * @throws NoSuchElementException if ds does not include an {@link OsmPrimitive} with id=<code>id</code>
113     */
114    protected void remember(DataSet ds, long id, OsmPrimitiveType type) throws IllegalArgumentException, NoSuchElementException{
115        CheckParameterUtil.ensureParameterNotNull(ds, "ds");
116        if (id <= 0) return;
117        OsmPrimitive primitive = ds.getPrimitiveById(id, type);
118        if (primitive == null)
119            throw new NoSuchElementException(tr("No primitive with id {0} in local dataset. Cannot infer primitive type.", id));
120        remember(primitive.getPrimitiveId());
121        return;
122    }
123
124    /**
125     * appends a {@link OsmPrimitive} id to the list of ids which will be fetched from the server.
126     *
127     * @param ds the {@link DataSet} to which the primitive belongs
128     * @param id the primitive id
129     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
130     * @return this
131     */
132    public MultiFetchServerObjectReader append(DataSet ds, long id, OsmPrimitiveType type) {
133        OsmPrimitive p = ds.getPrimitiveById(id,type);
134        switch(type) {
135        case NODE:
136            return appendNode((Node)p);
137        case WAY:
138            return appendWay((Way)p);
139        case RELATION:
140            return appendRelation((Relation)p);
141        }
142        return this;
143    }
144
145    /**
146     * appends a {@link Node} id to the list of ids which will be fetched from the server.
147     *
148     * @param node  the node (ignored, if null)
149     * @return this
150     */
151    public MultiFetchServerObjectReader appendNode(Node node) {
152        if (node == null) return this;
153        remember(node.getPrimitiveId());
154        return this;
155    }
156
157    /**
158     * appends a {@link Way} id and the list of ids of nodes the way refers to the list of ids which will be fetched from the server.
159     *
160     * @param way the way (ignored, if null)
161     * @return this
162     */
163    public MultiFetchServerObjectReader appendWay(Way way) {
164        if (way == null) return this;
165        if (way.isNew()) return this;
166        for (Node node: way.getNodes()) {
167            if (!node.isNew()) {
168                remember(node.getPrimitiveId());
169            }
170        }
171        remember(way.getPrimitiveId());
172        return this;
173    }
174
175    /**
176     * appends a {@link Relation} id to the list of ids which will be fetched from the server.
177     *
178     * @param relation  the relation (ignored, if null)
179     * @return this
180     */
181    protected MultiFetchServerObjectReader appendRelation(Relation relation) {
182        if (relation == null) return this;
183        if (relation.isNew()) return this;
184        remember(relation.getPrimitiveId());
185        for (RelationMember member : relation.getMembers()) {
186            if (OsmPrimitiveType.from(member.getMember()).equals(OsmPrimitiveType.RELATION)) {
187                // avoid infinite recursion in case of cyclic dependencies in relations
188                //
189                if (relations.contains(member.getMember().getId())) {
190                    continue;
191                }
192            }
193            if (!member.getMember().isIncomplete()) {
194                append(member.getMember());
195            }
196        }
197        return this;
198    }
199
200    /**
201     * appends an {@link OsmPrimitive} to the list of ids which will be fetched from the server.
202     * @param primitive the primitive
203     * @return this
204     */
205    public MultiFetchServerObjectReader append(OsmPrimitive primitive) {
206        if (primitive != null) {
207            switch (OsmPrimitiveType.from(primitive)) {
208                case NODE: return appendNode((Node)primitive);
209                case WAY: return appendWay((Way)primitive);
210                case RELATION: return appendRelation((Relation)primitive);
211            }
212        }
213        return this;
214    }
215
216    /**
217     * appends a list of {@link OsmPrimitive} to the list of ids which will be fetched from the server.
218     *
219     * @param primitives  the list of primitives (ignored, if null)
220     * @return this
221     *
222     * @see #append(OsmPrimitive)
223     */
224    public MultiFetchServerObjectReader append(Collection<? extends OsmPrimitive> primitives) {
225        if (primitives == null) return this;
226        for (OsmPrimitive primitive : primitives) {
227            append(primitive);
228        }
229        return this;
230    }
231
232    /**
233     * extracts a subset of max {@link #MAX_IDS_PER_REQUEST} ids from <code>ids</code> and
234     * replies the subset. The extracted subset is removed from <code>ids</code>.
235     *
236     * @param ids a set of ids
237     * @return the subset of ids
238     */
239    protected Set<Long> extractIdPackage(Set<Long> ids) {
240        HashSet<Long> pkg = new HashSet<Long>();
241        if (ids.isEmpty())
242            return pkg;
243        if (ids.size() > MAX_IDS_PER_REQUEST) {
244            Iterator<Long> it = ids.iterator();
245            for (int i=0; i<MAX_IDS_PER_REQUEST; i++) {
246                pkg.add(it.next());
247            }
248            ids.removeAll(pkg);
249        } else {
250            pkg.addAll(ids);
251            ids.clear();
252        }
253        return pkg;
254    }
255
256    /**
257     * builds the Multi Get request string for a set of ids and a given
258     * {@link OsmPrimitiveType}.
259     *
260     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
261     * @param idPackage  the package of ids
262     * @return the request string
263     */
264    protected static String buildRequestString(OsmPrimitiveType type, Set<Long> idPackage) {
265        StringBuilder sb = new StringBuilder();
266        sb.append(type.getAPIName()).append("s?")
267        .append(type.getAPIName()).append("s=");
268
269        Iterator<Long> it = idPackage.iterator();
270        for (int i=0; i<idPackage.size(); i++) {
271            sb.append(it.next());
272            if (i < idPackage.size()-1) {
273                sb.append(",");
274            }
275        }
276        return sb.toString();
277    }
278
279    /**
280     * builds the Multi Get request string for a single id and a given
281     * {@link OsmPrimitiveType}.
282     *
283     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
284     * @param id the id
285     * @return the request string
286     */
287    protected static String buildRequestString(OsmPrimitiveType type, long id) {
288        StringBuilder sb = new StringBuilder();
289        sb.append(type.getAPIName()).append("s?")
290        .append(type.getAPIName()).append("s=")
291        .append(id);
292        return sb.toString();
293    }
294
295    protected void rememberNodesOfIncompleteWaysToLoad(DataSet from) {
296        for (Way w: from.getWays()) {
297            if (w.hasIncompleteNodes()) {
298                for (Node n: w.getNodes()) {
299                    if (n.isIncomplete()) {
300                        nodes.add(n.getId());
301                    }
302                }
303            }
304        }
305    }
306
307    /**
308     * merges the dataset <code>from</code> to {@link #outputDataSet}.
309     *
310     * @param from the other dataset
311     */
312    protected void merge(DataSet from) {
313        final DataSetMerger visitor = new DataSetMerger(outputDataSet,from);
314        visitor.merge();
315    }
316
317    /**
318     * fetches a set of ids of a given {@link OsmPrimitiveType} from the server
319     *
320     * @param ids the set of ids
321     * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
322     * @throws OsmTransferException if an error occurs while communicating with the API server
323     */
324    protected void fetchPrimitives(Set<Long> ids, OsmPrimitiveType type, ProgressMonitor progressMonitor) throws OsmTransferException {
325        String msg = "";
326        String baseUrl = OsmApi.getOsmApi().getBaseUrl();
327        switch (type) {
328            case NODE:     msg = tr("Fetching a package of nodes from ''{0}''",     baseUrl); break;
329            case WAY:      msg = tr("Fetching a package of ways from ''{0}''",      baseUrl); break;
330            case RELATION: msg = tr("Fetching a package of relations from ''{0}''", baseUrl); break;
331        }
332        progressMonitor.setTicksCount(ids.size());
333        progressMonitor.setTicks(0);
334        // The complete set containg all primitives to fetch
335        Set<Long> toFetch = new HashSet<Long>(ids);
336        // Build a list of fetchers that will  download smaller sets containing only MAX_IDS_PER_REQUEST (200) primitives each.
337        // we will run up to MAX_DOWNLOAD_THREADS concurrent fetchers.
338        int threadsNumber = Main.pref.getInteger("osm.download.threads", OsmApi.MAX_DOWNLOAD_THREADS);
339        threadsNumber = Math.min(Math.max(threadsNumber, 1), OsmApi.MAX_DOWNLOAD_THREADS);
340        Executor exec = Executors.newFixedThreadPool(threadsNumber);
341        CompletionService<FetchResult> ecs = new ExecutorCompletionService<FetchResult>(exec);
342        List<Future<FetchResult>> jobs = new ArrayList<Future<FetchResult>>();
343        while (!toFetch.isEmpty()) {
344            jobs.add(ecs.submit(new Fetcher(type, extractIdPackage(toFetch), progressMonitor)));
345        }
346        // Run the fetchers
347        for (int i = 0; i < jobs.size() && !isCanceled(); i++) {
348            progressMonitor.subTask(msg + "... " + progressMonitor.getTicks() + "/" + progressMonitor.getTicksCount());
349            try {
350                FetchResult result = ecs.take().get();
351                if (result.missingPrimitives != null) {
352                    missingPrimitives.addAll(result.missingPrimitives);
353                }
354                if (result.dataSet != null && !isCanceled()) {
355                    rememberNodesOfIncompleteWaysToLoad(result.dataSet);
356                    merge(result.dataSet);
357                }
358            } catch (InterruptedException e) {
359                e.printStackTrace();
360            } catch (ExecutionException e) {
361                e.printStackTrace();
362            }
363        }
364        // Cancel requests if the user choosed to
365        if (isCanceled()) {
366            for (Future<FetchResult> job : jobs) {
367                job.cancel(true);
368            }
369        }
370    }
371
372    /**
373     * invokes one or more Multi Gets to fetch the {@link OsmPrimitive}s and replies
374     * the dataset of retrieved primitives. Note that the dataset includes non visible primitives too!
375     * In contrast to a simple Get for a node, a way, or a relation, a Multi Get always replies
376     * the latest version of the primitive (if any), even if the primitive is not visible (i.e. if
377     * visible==false).
378     *
379     * Invoke {@link #getMissingPrimitives()} to get a list of primitives which have not been
380     * found on  the server (the server response code was 404)
381     *
382     * @return the parsed data
383     * @throws OsmTransferException if an error occurs while communicating with the API server
384     * @see #getMissingPrimitives()
385     *
386     */
387    @Override
388    public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
389        int n = nodes.size() + ways.size() + relations.size();
390        progressMonitor.beginTask(trn("Downloading {0} object from ''{1}''", "Downloading {0} objects from ''{1}''", n, n, OsmApi.getOsmApi().getBaseUrl()));
391        try {
392            missingPrimitives = new HashSet<PrimitiveId>();
393            if (isCanceled()) return null;
394            fetchPrimitives(ways,OsmPrimitiveType.WAY, progressMonitor);
395            if (isCanceled()) return null;
396            fetchPrimitives(nodes,OsmPrimitiveType.NODE, progressMonitor);
397            if (isCanceled()) return null;
398            fetchPrimitives(relations,OsmPrimitiveType.RELATION, progressMonitor);
399            if (outputDataSet != null) {
400                outputDataSet.deleteInvisible();
401            }
402            return outputDataSet;
403        } finally {
404            progressMonitor.finishTask();
405        }
406    }
407
408    /**
409     * replies the set of ids of all primitives for which a fetch request to the
410     * server was submitted but which are not available from the server (the server
411     * replied a return code of 404)
412     *
413     * @return the set of ids of missing primitives
414     */
415    public Set<PrimitiveId> getMissingPrimitives() {
416        return missingPrimitives;
417    }
418
419    /**
420     * The class holding the results given by {@link Fetcher}.
421     * It is only a wrapper of the resulting {@link DataSet} and the collection of {@link PrimitiveId} that could not have been loaded.
422     */
423    protected static class FetchResult {
424
425        /**
426         * The resulting data set
427         */
428        public final DataSet dataSet;
429
430        /**
431         * The collection of primitive ids that could not have been loaded
432         */
433        public final Set<PrimitiveId> missingPrimitives;
434
435        /**
436         * Constructs a {@code FetchResult}
437         * @param dataSet The resulting data set
438         * @param missingPrimitives The collection of primitive ids that could not have been loaded
439         */
440        public FetchResult(DataSet dataSet, Set<PrimitiveId> missingPrimitives) {
441            this.dataSet = dataSet;
442            this.missingPrimitives = missingPrimitives;
443        }
444    }
445
446    /**
447     * The class that actually download data from OSM API. Several instances of this class are used by {@link MultiFetchServerObjectReader} (one per set of primitives to fetch).
448     * The inheritance of {@link OsmServerReader} is only explained by the need to have a distinct OSM connection by {@code Fetcher} instance.
449     * @see FetchResult
450     */
451    protected static class Fetcher extends OsmServerReader implements Callable<FetchResult> {
452
453        private final Set<Long> pkg;
454        private final OsmPrimitiveType type;
455        private final ProgressMonitor progressMonitor;
456
457        /**
458         * Constructs a {@code Fetcher}
459         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
460         * @param idsPackage The set of primitives ids to fetch
461         * @param progressMonitor The progress monitor
462         */
463        public Fetcher(OsmPrimitiveType type, Set<Long> idsPackage, ProgressMonitor progressMonitor) {
464            this.pkg = idsPackage;
465            this.type = type;
466            this.progressMonitor = progressMonitor;
467        }
468
469        @Override
470        public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferException {
471            // This method is implemented because of the OsmServerReader inheritance, but not used, as the main target of this class is the call() method.
472            return fetch(progressMonitor).dataSet;
473        }
474
475        @Override
476        public FetchResult call() throws Exception {
477            return fetch(progressMonitor);
478        }
479
480        /**
481         * fetches the requested primitives and updates the specified progress monitor.
482         * @param progressMonitor the progress monitor
483         * @return the {@link FetchResult} of this operation
484         * @throws OsmTransferException if an error occurs while communicating with the API server
485         */
486        protected FetchResult fetch(ProgressMonitor progressMonitor) throws OsmTransferException {
487            try {
488                return multiGetIdPackage(type, pkg, progressMonitor);
489            } catch (OsmApiException e) {
490                if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
491                    Main.info(tr("Server replied with response code 404, retrying with an individual request for each object."));
492                    return singleGetIdPackage(type, pkg, progressMonitor);
493                } else {
494                    throw e;
495                }
496            }
497        }
498
499        /**
500         * invokes a Multi Get for a set of ids and a given {@link OsmPrimitiveType}.
501         * The retrieved primitives are merged to {@link #outputDataSet}.
502         *
503         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
504         * @param pkg the package of ids
505         * @return the {@link FetchResult} of this operation
506         * @throws OsmTransferException if an error occurs while communicating with the API server
507         */
508        protected FetchResult multiGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor) throws OsmTransferException {
509            String request = buildRequestString(type, pkg);
510            final InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE);
511            if (in == null) return null;
512            progressMonitor.subTask(tr("Downloading OSM data..."));
513            try {
514                return new FetchResult(OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(pkg.size(), false)), null);
515            } catch (Exception e) {
516                throw new OsmTransferException(e);
517            }
518        }
519
520        /**
521         * invokes a Multi Get for a single id and a given {@link OsmPrimitiveType}.
522         * The retrieved primitive is merged to {@link #outputDataSet}.
523         *
524         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
525         * @param id the id
526         * @return the {@link DataSet} resulting of this operation
527         * @throws OsmTransferException if an error occurs while communicating with the API server
528         */
529        protected DataSet singleGetId(OsmPrimitiveType type, long id, ProgressMonitor progressMonitor) throws OsmTransferException {
530            String request = buildRequestString(type, id);
531            final InputStream in = getInputStream(request, NullProgressMonitor.INSTANCE);
532            if (in == null) return null;
533            progressMonitor.subTask(tr("Downloading OSM data..."));
534            try {
535                return OsmReader.parseDataSet(in, progressMonitor.createSubTaskMonitor(1, false));
536            } catch (Exception e) {
537                throw new OsmTransferException(e);
538            }
539        }
540
541        /**
542         * invokes a sequence of Multi Gets for individual ids in a set of ids and a given {@link OsmPrimitiveType}.
543         * The retrieved primitives are merged to {@link #outputDataSet}.
544         *
545         * This method is used if one of the ids in pkg doesn't exist (the server replies with return code 404).
546         * If the set is fetched with this method it is possible to find out which of the ids doesn't exist.
547         * Unfortunately, the server does not provide an error header or an error body for a 404 reply.
548         *
549         * @param type The primitive type. Must be one of {@link OsmPrimitiveType#NODE NODE}, {@link OsmPrimitiveType#WAY WAY}, {@link OsmPrimitiveType#RELATION RELATION}
550         * @param pkg the set of ids
551         * @return the {@link FetchResult} of this operation
552         * @throws OsmTransferException if an error occurs while communicating with the API server
553         */
554        protected FetchResult singleGetIdPackage(OsmPrimitiveType type, Set<Long> pkg, ProgressMonitor progressMonitor) throws OsmTransferException {
555            FetchResult result = new FetchResult(new DataSet(), new HashSet<PrimitiveId>());
556            String baseUrl = OsmApi.getOsmApi().getBaseUrl();
557            for (long id : pkg) {
558                try {
559                    String msg = "";
560                    switch (type) {
561                        case NODE:     msg = tr("Fetching node with id {0} from ''{1}''",     id, baseUrl); break;
562                        case WAY:      msg = tr("Fetching way with id {0} from ''{1}''",      id, baseUrl); break;
563                        case RELATION: msg = tr("Fetching relation with id {0} from ''{1}''", id, baseUrl); break;
564                    }
565                    progressMonitor.setCustomText(msg);
566                    result.dataSet.mergeFrom(singleGetId(type, id, progressMonitor));
567                } catch (OsmApiException e) {
568                    if (e.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND) {
569                        Main.info(tr("Server replied with response code 404 for id {0}. Skipping.", Long.toString(id)));
570                        result.missingPrimitives.add(new SimplePrimitiveId(id, type));
571                    } else {
572                        throw e;
573                    }
574                }
575            }
576            return result;
577        }
578    }
579}