Added method to extract a set of allowed methods from the OPTIONS response

git-svn-id: https://svn.apache.org/repos/asf/jakarta/httpcomponents/httpclient/trunk@528488 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/http/client/methods/HttpOptions.java

@@ -33,6 +33,13 @@ package org.apache.http.client.methods;
 
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.apache.http.Header;
+import org.apache.http.HeaderElement;
+import org.apache.http.HttpResponse;
 
 /**
  * HTTP OPTIONS method.
@@ -75,4 +82,20 @@ public class HttpOptions extends HttpRequestBase {
         return METHOD_NAME;
     }
     
+    public Set getAllowedMethods(final HttpResponse response) {
+        if (response == null) {
+            throw new IllegalArgumentException("HTTP response may not be null");
+        }
+        Header header = response.getFirstHeader("Allow");
+        if (header == null) {
+            return Collections.EMPTY_SET;
+        }
+        HeaderElement[] elements = header.getElements();
+        Set methods = new HashSet(elements.length);
+        for (int i = 0; i < elements.length; i++) {
+            methods.add(elements[i].getName());
+        }
+        return methods;
+    }
+    
 }