---
title: Creating a Server-Side Component
order: 3
layout: page
---

[[gwt.server-side]]
= Creating a Server-Side Component

Typical server-side Vaadin applications use server-side components that are
rendered on the client-side using their counterpart widgets. A server-side
component must manage state synchronization between the widget on the
client-side, in addition to any server-side logic.

[[gwt.server-side.basic]]
== Basic Server-Side Component

The component state is usually managed by a __shared state__, described later in
<<dummy/../../../framework/gwt/gwt-shared-state#gwt.shared-state,"Shared
State">>.


----
public class MyComponent extends AbstractComponent {
    public MyComponent() {
        getState().setText("This is MyComponent");
    }

    @Override
    protected MyComponentState getState() {
        return (MyComponentState) super.getState();
    }
}
----




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<td class='lines'><pre><code><style>pre { line-height: 125%; }
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<span class="c1"># Redmine - project management software</span>
<span class="c1"># Copyright (C) 2006-2017  Jean-Philippe Lang</span>
<span class="c1">#</span>
<span class="c1"># This program is free software; you can redistribute it and/or</span>
<span class="c1"># modify it under the terms of the GNU General Public License</span>
<span class="c1"># as published by the Free Software Foundation; either version 2</span>
<span class="c1"># of the License, or (at your option) any later version.</span>
<span class="c1">#</span>
<span class="c1"># This program is distributed in the hope that it will be useful,</span>
<span class="c1"># but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<span class="c1"># MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the</span>
<span class="c1"># GNU General Public License for more details.</span>
<span class="c1">#</span>
<span class="c1"># You should have received a copy of the GNU General Public License</span>
<span class="c1"># along with this program; if not, write to the Free Software</span>
<span class="c1"># Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.</span>

<span class="nb">require</span><span class="w"> </span><span class="no">File</span><span class="o">.</span><span class="n">expand_path</span><span class="p">(</span><span class="s1">&#39;../../../test_helper&#39;</span><span class="p">,</span><span class="w"> </span><span class="bp">__FILE__</span><span class="p">)</span>

<span class="k">class</span><span class="w"> </span><span class="nc">RoutingEnumerationsTest</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="no">Redmine</span><span class="o">::</span><span class="no">RoutingTest</span>
<span class="w">  </span><span class="k">def</span><span class="w"> </span><span class="nf">test_enumerations</span>
<span class="w">    </span><span class="n">should_route</span><span class="w"> </span><span class="s1">&#39;GET /enumerations&#39;</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;enumerations#index&#39;</span>
<span class="w">    </span><span class="n">should_route</span><span class="w"> </span><span class="s1">&#39;GET /enumerations/new&#39;</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;enumerations#new&#39;</span>
<span class="w">    </span><span class="n">should_route</span><span class="w"> </span><span class="s1">&#39;POST /enumerations&#39;</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;enumerations#create&#39;</span>

<span class="w">    </span><span class="n">should_route</span><span class="w"> </span><span class="s1">&#39;GET /enumerations/2/edit&#39;</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;enumerations#edit&#39;</span><span class="p">,</span><span class="w"> </span><span class="ss">:id</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;2&#39;</span>
<span class="w">    </span><span class="n">should_route</span><span class="w"> </span><span class="s1">&#39;PUT /enumerations/2&#39;</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;enumerations#update&#39;</span><span class="p">,</span><span class="w"> </span><span class="ss">:id</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;2&#39;</span>
<span class="w">    </span><span class="n">should_route</span><span class="w"> </span><span class="s1">&#39;DELETE /enumerations/2&#39;</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;enumerations#destroy&#39;</span><span class="p">,</span><span class="w"> </span><span class="ss">:id</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="s1">&#39;2&#39;</span>
<span class="w">  </span><span class="k">end</span>
<span class="k">end</span>
</pre></div>
