Index: trunk/src/oauth/signpost/http/HttpParameters.java
===================================================================
--- trunk/src/oauth/signpost/http/HttpParameters.java	(revision 4231)
+++ trunk/src/oauth/signpost/http/HttpParameters.java	(revision 6849)
@@ -87,16 +87,18 @@
      */
     public String put(String key, String value, boolean percentEncode) {
-        SortedSet<String> values = wrappedMap.get(key);
-        if (values == null) {
-            values = new TreeSet<String>();
-            wrappedMap.put(percentEncode ? OAuth.percentEncode(key) : key, values);
-        }
-        if (value != null) {
-            value = percentEncode ? OAuth.percentEncode(value) : value;
-            values.add(value);
-        }
-
-        return value;
-    }
+         // fix contributed by Bjorn Roche - key should be encoded before wrappedMap.get
+         key = percentEncode ? OAuth.percentEncode(key) : key;
+         SortedSet<String> values = wrappedMap.get(key);
+         if (values == null) {
+             values = new TreeSet<String>();
+             wrappedMap.put( key, values);
+         }
+         if (value != null) {
+             value = percentEncode ? OAuth.percentEncode(value) : value;
+             values.add(value);
+         }
+
+         return value;
+     }
 
     /**
@@ -200,6 +202,26 @@
      */
     public String getAsQueryString(Object key) {
+    	return getAsQueryString(key, true);
+    }
+
+    /**
+     * Concatenates all values for the given key to a list of key/value pairs
+     * suitable for use in a URL query string.
+     * 
+     * @param key
+     *        the parameter name
+     * @param percentEncode
+     *        whether key should be percent encoded before being
+     *        used with the map
+     * @return the query string
+     */
+     public String getAsQueryString(Object key, boolean percentEncode) {
+        // fix contributed by Stjepan Rajko - we need the percentEncode parameter
+        // because some places (like SignatureBaseString.normalizeRequestParameters)
+        // need to supply the parameter percent encoded
+
         StringBuilder sb = new StringBuilder();
-        key = OAuth.percentEncode((String) key);
+        if(percentEncode)
+        	key = OAuth.percentEncode((String) key);
         Set<String> values = wrappedMap.get(key);
         if (values == null) {
@@ -215,5 +237,5 @@
         return sb.toString();
     }
-
+    
     public String getAsHeaderElement(String key) {
         String value = getFirst(key);
@@ -265,6 +287,19 @@
     }
 
-    public Set<java.util.Map.Entry<String, SortedSet<String>>> entrySet() {
+    public Set<Entry<String, SortedSet<String>>> entrySet() {
         return wrappedMap.entrySet();
     }
+
+    public HttpParameters getOAuthParameters() {
+        HttpParameters oauthParams = new HttpParameters();
+
+        for (Entry<String, SortedSet<String>> param : this.entrySet()) {
+            String key = param.getKey();
+            if (key.startsWith("oauth_") || key.startsWith("x_oauth_")) {
+                oauthParams.put(key, param.getValue());
+            }
+        }
+
+        return oauthParams;
+    }
 }