Add request change filter.

diff --git a/src/main/java/net/pterodactylus/sone/template/RequestChangeFilter.java b/src/main/java/net/pterodactylus/sone/template/RequestChangeFilter.java
new file mode 100644 (file)
index 0000000..d9c453e
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sone/template/RequestChangeFilter.java
@@ -0,0 +1,93 @@
+/*
+ * Sone - RequestChangeFilter.java - Copyright © 2010 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.sone.template;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URLEncoder;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import net.pterodactylus.sone.web.page.Page.Request;
+import net.pterodactylus.util.template.DataProvider;
+import net.pterodactylus.util.template.Filter;
+
+/**
+ * This filter expects a {@link Request} as input and outputs a {@link URI} that
+ * is modified by the parameters. The name of the parameter is handed in as
+ * “name”, the value may either be stored in “value”, or in a template variable
+ * whose key is stored in “key”.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class RequestChangeFilter implements Filter {
+
+       /**
+        * {@inheritDoc}
+        */
+       @Override
+       public Object format(DataProvider dataProvider, Object data, Map<String, String> parameters) {
+               Request request = (Request) data;
+               String name = parameters.get("name");
+               String key = parameters.get("key");
+               String value = null;
+               if (key != null) {
+                       value = String.valueOf(dataProvider.getData(key));
+               }
+               if (value == null) {
+                       value = parameters.get("value");
+               }
+               if (value == null) {
+                       return request.getUri();
+               }
+
+               Map<String, String> values = new HashMap<String, String>();
+               Collection<String> parameterNames = request.getHttpRequest().getParameterNames();
+               for (String parameterName : parameterNames) {
+                       values.put(parameterName, request.getHttpRequest().getParam(parameterName));
+               }
+               values.put(name, value);
+
+               StringBuilder query = new StringBuilder();
+               try {
+                       for (Entry<String, String> parameterEntry : values.entrySet()) {
+                               query.append((query.length() == 0) ? '?' : '&');
+                               query.append(URLEncoder.encode(parameterEntry.getKey(), "UTF-8"));
+                               query.append('=');
+                               query.append(URLEncoder.encode(parameterEntry.getValue(), "UTF-8"));
+                       }
+                       String oldUri = request.getUri().toString();
+                       int questionMark = oldUri.indexOf('?');
+                       if (questionMark == -1) {
+                               questionMark = oldUri.length();
+                       }
+                       URI u = new URI(oldUri.substring(0, questionMark) + query.toString());
+                       System.out.println("u: " + u);
+                       return u;
+               } catch (UnsupportedEncodingException uee1) {
+                       /* UTF-8 not supported? I don’t think so. */
+               } catch (URISyntaxException use1) {
+                       use1.printStackTrace();
+               }
+               return null;
+       }
+
+}