ThemesPhotoCollectionProvider.java
- /*
- * *********************************************************************************************************************
- *
- * blueMarine II: Semantic Media Centre
- * http://tidalwave.it/projects/bluemarine2
- *
- * Copyright (C) 2015 - 2021 by Tidalwave s.a.s. (http://tidalwave.it)
- *
- * *********************************************************************************************************************
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
- * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
- * specific language governing permissions and limitations under the License.
- *
- * *********************************************************************************************************************
- *
- * git clone https://bitbucket.org/tidalwave/bluemarine2-src
- * git clone https://github.com/tidalwave-it/bluemarine2-src
- *
- * *********************************************************************************************************************
- */
- package it.tidalwave.bluemarine2.service.stoppingdown.impl;
- import javax.annotation.Nonnull;
- import java.util.ArrayList;
- import java.util.Collection;
- import java.util.concurrent.ConcurrentHashMap;
- import java.util.List;
- import java.util.Map;
- import java.io.IOException;
- import java.nio.file.Paths;
- import java.nio.file.Path;
- import javax.xml.parsers.ParserConfigurationException;
- import javax.xml.xpath.XPath;
- import javax.xml.xpath.XPathExpression;
- import javax.xml.xpath.XPathExpressionException;
- import it.tidalwave.util.annotation.VisibleForTesting;
- import org.xml.sax.SAXException;
- import org.w3c.dom.Document;
- import org.w3c.dom.Node;
- import org.w3c.dom.NodeList;
- import it.tidalwave.bluemarine2.model.MediaFolder;
- import it.tidalwave.bluemarine2.model.VirtualMediaFolder;
- import it.tidalwave.bluemarine2.model.spi.PathAwareEntity;
- import it.tidalwave.bluemarine2.model.spi.PathAwareFinder;
- import lombok.extern.slf4j.Slf4j;
- import static java.util.Comparator.comparing;
- import static java.util.stream.Collectors.*;
- import static javax.xml.xpath.XPathConstants.*;
- /***********************************************************************************************************************
- *
- * @author Fabrizio Giudici
- *
- **********************************************************************************************************************/
- @Slf4j
- public class ThemesPhotoCollectionProvider extends PhotoCollectionProviderSupport
- {
- private static final String URL_THEMES_TEMPLATE = "%s/themes/";
- private static final Path PATH_SUBJECTS = Paths.get("subjects");
- private static final Path PATH_PLACES = Paths.get("places");
- @VisibleForTesting static final XPathExpression XPATH_SUBJECTS_THUMBNAIL_EXPR;
- @VisibleForTesting static final XPathExpression XPATH_PLACES_THUMBNAIL_EXPR;
- private static final XPathExpression XPATH_THUMBNAIL_URL_EXPR;
- private static final XPathExpression XPATH_THUMBNAIL_DESCRIPTION_EXPR;
- /**
- * A local cache for themes is advisable because multiple calls will be performed.
- */
- private final Map<XPathExpression, List<GalleryDescription>> themesCache = new ConcurrentHashMap<>();
- /*******************************************************************************************************************
- *
- ******************************************************************************************************************/
- static
- {
- try
- {
- final XPath xpath = XPATH_FACTORY.newXPath();
- // XPATH_SUBJECTS_THUMBNAIL_EXPR = xpath.compile("//div[@class='container-fluid']/h3[1]/following-sibling::div[@class='thumbnail']");
- // XPATH_PLACES_THUMBNAIL_EXPR = xpath.compile("//div[@class='container-fluid']/h3[2]/following-sibling::div[@class='thumbnail']");
- XPATH_SUBJECTS_THUMBNAIL_EXPR = xpath.compile("//div[@class='container-fluid']/div[@class='row'][1]//div[@class='thumbnail']");
- XPATH_PLACES_THUMBNAIL_EXPR = xpath.compile("//div[@class='container-fluid']/div[@class='row'][2]//div[@class='thumbnail']");
- XPATH_THUMBNAIL_URL_EXPR = xpath.compile("a/@href");
- XPATH_THUMBNAIL_DESCRIPTION_EXPR = xpath.compile(".//div[@class='caption']/h3/text()");
- }
- catch (XPathExpressionException e)
- {
- throw new ExceptionInInitializerError(e);
- }
- }
- /*******************************************************************************************************************
- *
- ******************************************************************************************************************/
- public ThemesPhotoCollectionProvider()
- {
- this(URL_STOPPINGDOWN);
- }
- /*******************************************************************************************************************
- *
- ******************************************************************************************************************/
- public ThemesPhotoCollectionProvider (@Nonnull final String baseUrl)
- {
- super(baseUrl);
- }
- /*******************************************************************************************************************
- *
- * {@inheritDoc}
- *
- ******************************************************************************************************************/
- @Override @Nonnull
- public PathAwareFinder findPhotos (@Nonnull final MediaFolder parent)
- {
- return parent.finderOf(p -> List.of(
- new VirtualMediaFolder(p, PATH_PLACES, "Places", this::placesFactory),
- new VirtualMediaFolder(p, PATH_SUBJECTS, "Subjects", this::subjectsFactory)));
- }
- /*******************************************************************************************************************
- *
- * {@inheritDoc}
- *
- ******************************************************************************************************************/
- @Override
- protected void clearCachesImpl()
- {
- super.clearCachesImpl();
- themesCache.clear();
- }
- /*******************************************************************************************************************
- *
- ******************************************************************************************************************/
- @Nonnull
- private Collection<PathAwareEntity> subjectsFactory (@Nonnull final MediaFolder parent)
- {
- return parseThemes(XPATH_SUBJECTS_THUMBNAIL_EXPR).stream()
- .map(gallery -> gallery.createFolder(parent, this::findPhotos))
- .collect(toList());
- }
- /*******************************************************************************************************************
- *
- ******************************************************************************************************************/
- @Nonnull
- private Collection<PathAwareEntity> placesFactory (@Nonnull final MediaFolder parent)
- {
- return parseThemes(XPATH_PLACES_THUMBNAIL_EXPR).stream()
- .map(gallery -> gallery.createFolder(parent, this::findPhotos))
- .collect(toList());
- }
- /*******************************************************************************************************************
- *
- ******************************************************************************************************************/
- @Nonnull
- @VisibleForTesting List<GalleryDescription> parseThemes (@Nonnull final XPathExpression expr)
- {
- final String themeUrl = String.format(URL_THEMES_TEMPLATE, baseUrl);
- log.debug("parseThemes({}, {})", themeUrl, expr);
- return themesCache.computeIfAbsent(expr, key ->
- {
- try
- {
- final Document document = downloadXml(themeUrl);
- final NodeList thumbnailNodes = (NodeList)expr.evaluate(document, NODESET);
- final List<GalleryDescription> galleryDescriptions = new ArrayList<>();
- for (int i = 0; i < thumbnailNodes.getLength(); i++)
- {
- final Node thumbnailNode = thumbnailNodes.item(i);
- final String description = (String)XPATH_THUMBNAIL_DESCRIPTION_EXPR.evaluate(thumbnailNode, STRING);
- final String href = (String)XPATH_THUMBNAIL_URL_EXPR.evaluate(thumbnailNode, STRING);
- final String url = String.format(URL_GALLERY_TEMPLATE, baseUrl, href).replace("//", "/")
- .replace(":/", "://");
- galleryDescriptions.add(new GalleryDescription(description, url));
- }
- galleryDescriptions.sort(comparing(GalleryDescription::getDisplayName));
- return galleryDescriptions;
- }
- catch (SAXException | IOException | XPathExpressionException | ParserConfigurationException e)
- {
- throw new RuntimeException(e);
- }
- });
- }
- }