From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Tue, 26 Feb 2013 20:52:22 +0000 (+0100)
Subject: Add filter that extracts a URL from an HTML state and turns it into a String state.
X-Git-Tag: v2~310
X-Git-Url: https://git.pterodactylus.net/?a=commitdiff_plain;h=0156c50c7da8c28453caf855cda6bb6ce088aab8;p=rhynodge.git

Add filter that extracts a URL from an HTML state and turns it into a String state.
---

diff --git a/src/main/java/net/pterodactylus/rhynodge/filters/ExtractUrlFilter.java b/src/main/java/net/pterodactylus/rhynodge/filters/ExtractUrlFilter.java
new file mode 100644
index 0000000..b075686
--- /dev/null
+++ b/src/main/java/net/pterodactylus/rhynodge/filters/ExtractUrlFilter.java
@@ -0,0 +1,67 @@
+/*
+ * rhynodge - HttpQueryFilter.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 net.pterodactylus.rhynodge.Filter;
+import net.pterodactylus.rhynodge.State;
+import net.pterodactylus.rhynodge.states.FailedState;
+import net.pterodactylus.rhynodge.states.HtmlState;
+import net.pterodactylus.rhynodge.states.StringState;
+
+import com.google.common.base.Optional;
+import org.jsoup.nodes.Document;
+
+/**
+ * {@link Filter} implementation that extracts a URL from an {@link HtmlState}.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public abstract class ExtractUrlFilter implements Filter {
+
+	@Override
+	public State filter(State state) {
+		checkArgument(state instanceof HtmlState, "state must be an HTML state");
+
+		HtmlState htmlState = (HtmlState) state;
+		Optional<String> newUrl = extractUrl(htmlState.document());
+
+		if (!newUrl.isPresent()) {
+			return new FailedState();
+		}
+
+		return new StringState(newUrl.get());
+	}
+
+	//
+	// PROTECTED METHODS
+	//
+
+	/**
+	 * Extracts the URL from the given document. If the returned value is {@link
+	 * Optional#absent()}, {@link #filter(State)} will return a {@link
+	 * FailedState}.
+	 *
+	 * @param document
+	 * 		The document to extract the URL from
+	 * @return The extracted URL, or {@link Optional#absent()}
+	 */
+	protected abstract Optional<String> extractUrl(Document document);
+
+}