Add filter for comic sites.

diff --git a/src/main/java/net/pterodactylus/rhynodge/filters/ComicSiteFilter.java b/src/main/java/net/pterodactylus/rhynodge/filters/ComicSiteFilter.java
new file mode 100644 (file)
index 0000000..5f6a11e
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+++ b/src/main/java/net/pterodactylus/rhynodge/filters/ComicSiteFilter.java
@@ -0,0 +1,88 @@
+/*
+ * rhynodge - ComicFilter.java - Copyright © 2013 David Roden
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.rhynodge.filters;
+
+import static com.google.common.base.Preconditions.*;
+
+import java.util.List;
+
+import net.pterodactylus.rhynodge.Filter;
+import net.pterodactylus.rhynodge.State;
+import net.pterodactylus.rhynodge.states.ComicState;
+import net.pterodactylus.rhynodge.states.ComicState.Comic;
+import net.pterodactylus.rhynodge.states.HtmlState;
+
+import com.google.common.base.Optional;
+import org.jsoup.nodes.Document;
+
+/**
+ * {@link Filter} implementation that can extract {@link ComicState}s from
+ * {@link HtmlState}s.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public abstract class ComicSiteFilter implements Filter {
+
+       @Override
+       public State filter(State state) {
+               checkArgument(state instanceof HtmlState, "state must be an HTML state");
+
+               /* initialize states: */
+               HtmlState htmlState = (HtmlState) state;
+               ComicState comicState = new ComicState();
+
+               /* extract comics. */
+               Optional<String> title = extractTitle(htmlState.document());
+               List<String> imageUrls = extractImageUrls(htmlState.document());
+
+               /* store comic, if found, into state. */
+               if (title.isPresent() && !imageUrls.isEmpty()) {
+                       Comic comic = new Comic(title.get());
+                       for (String imageUrl : imageUrls) {
+                               comic.addImageUrl(imageUrl);
+                       }
+               }
+
+               return comicState;
+       }
+
+       //
+       // PROTECTED METHODS
+       //
+
+       /**
+        * Extracts the title of the comic from the given document.
+        *
+        * @param document
+        *              The document to extract the title from
+        * @return The extracted title, or {@link Optional#absent()}} if no title could
+        *         be found
+        */
+       protected abstract Optional<String> extractTitle(Document document);
+
+       /**
+        * Extracts the image URLs from the given document.
+        *
+        * @param document
+        *              The document to extract the image URLs from
+        * @return The extracted image URLs, or an empty list if no URLs could be
+        *         found
+        */
+       protected abstract List<String> extractImageUrls(Document document);
+
+}