415047 - Create URIs lazily in HttpClient.

URIs are now created lazily, although a call to Request.getURI() is
made anyway for each request sending (and therefore the URI is
created anyway for each send). However, we save creating multiple
URIs in case the scheme, path, query or params are changed before
sending the request.

jetty-client/src/main/java/org/eclipse/jetty/client/HttpRequest.java

@@ -90,7 +90,6 @@ public class HttpRequest implements Request
         path = uri.getRawPath();
         query = uri.getRawQuery();
         extractParams(query);
-        this.uri = buildURI(true);
         followRedirects(client.isFollowRedirects());
         idleTimeout = client.getIdleTimeout();
         HttpField acceptEncodingField = client.getAcceptEncodingField();
@@ -115,7 +114,7 @@ public class HttpRequest implements Request
     public Request scheme(String scheme)
     {
         this.scheme = scheme;
-        this.uri = buildURI(true);
+        this.uri = null;
         return this;
     }
 
@@ -173,9 +172,9 @@ public class HttpRequest implements Request
             params.clear();
             extractParams(query);
         }
-        this.uri = buildURI(true);
         if (uri.isAbsolute())
             this.path = buildURI(false).toString();
+        this.uri = null;
         return this;
     }
 
@@ -188,7 +187,9 @@ public class HttpRequest implements Request
     @Override
     public URI getURI()
     {
-        return uri;
+        if (uri != null)
+            return uri;
+        return uri = buildURI(true);
     }
 
     @Override
@@ -209,7 +210,7 @@ public class HttpRequest implements Request
     {
         params.add(name, value);
         this.query = buildQuery();
-        this.uri = buildURI(true);
+        this.uri = null;
         return this;
     }
 
@@ -272,6 +273,7 @@ public class HttpRequest implements Request
     }
 
     @Override
+    @SuppressWarnings("unchecked")
     public <T extends RequestListener> List<T> getRequestListeners(Class<T> type)
     {
         // This method is invoked often in a request/response conversation,