* Licensed to the Apache Software Foundation (ASF) under one or more

* contributor license agreements.  See the NOTICE file distributed with

* this work for additional information regarding copyright ownership.

* The ASF licenses this file to You under the Apache License, Version 2.0

* (the "License"); you may not use this file except in compliance with

* the License.  You may obtain a copy of the License at

*

*      http://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

* Panel (has it's own markup, defined between <wicket:panel> tags), that can act as a form

* component. It typically wouldn't receive any input yourself, and often you can get by with

* nesting form components in panels proper. However, using this panel can help you with building

* components act to the outside world as one component, but internally uses separate components.

* This component would then use these nested components to handle it's internal state, and would

* use that internal state to get to one model object.

* <p>

* It is recommended that you override {@link #convertInput()} and let it set the value that

* represents the compound value of the nested components. Often, this goes hand-in-hand with

* overriding {@link #onBeforeRender()}, where you would analyze the model value, break it up and

* distribute the appropriate values over the child components.

* </p>

*

* <p>

* Here is a simple example of a panel with two components that multiplies and sets that as the

* master model object. Note that for this simple example, setting the model value wouldn't make

* sense, as the lhs and rhs cannot be known. For more complete examples of using this class, see

* the wicket-datetime project.

* </p>

*

* <pre>

* public class Multiply extends FormComponentPanel

* {

*   private TextField left;

*   private int lhs = 0;

*   private int rhs = 0;

*   private TextField right;

*

*   public Multiply(String id)

*   {

*     super(id);

*     init();

*   }

*

*   public Multiply(String id, IModel model)

*   {

*     super(id, model);

*     init();

*   }

*

*   protected void convertInput()

*   {

*     Integer lhs = (Integer)left.getConvertedInput();

*     Integer rhs = (Integer)right.getConvertedInput();

*     setConvertedInput(lhs * rhs);

*   }

*

*   private void init()

*   {

*     add(left = new TextField(&quot;left&quot;, new PropertyModel(this, &quot;lhs&quot;), Integer.class));

*     add(right = new TextField(&quot;right&quot;, new PropertyModel(this, &quot;rhs&quot;), Integer.class));

*     left.setRequired(true);

*     right.setRequired(true);

*   }

* }

* </pre>

*

* With this markup:

*

* <pre>

*   &lt;wicket:panel&gt;

*     &lt;input type=&quot;text&quot; wicket:id=&quot;left&quot; size=&quot;2&quot; /&gt; * &lt;input type=&quot;text&quot; wicket:id=&quot;right&quot; size=&quot;2&quot; /&gt;

*   &lt;/wicket:panel&gt;

* </pre>

*

* Which could be used, for example as:

*

* <pre>

*   add(new Multiply(&quot;multiply&quot;), new PropertyModel(m, &quot;multiply&quot;)));

*   add(new Label(&quot;multiplyLabel&quot;, new PropertyModel(m, &quot;multiply&quot;)));

* </pre>

*

* and:

*

* <pre>

*   &lt;span wicket:id=&quot;multiply&quot;&gt;[multiply]&lt;/span&gt;

*   = &lt;span wicket:id=&quot;multiplyLabel&quot;&gt;[result]&lt;/span&gt;

* </pre>

*

* </p>

*

* @author eelcohillenius

*

* @param <T>

*            The model object type

*/

  private static final long serialVersionUID = 1L;

  static

  {

    // register "wicket:panel"

    // Same as in Panel.java. Not that it can be moved in the PanelMarkupSourcingStrategy which

    // provides common functionality for Panel and FormComponentPanel, since the sourcing

    // strategy gets lazy loaded. Too late as some users found out.

    WicketTagIdentifier.registerWellKnownTagName(Panel.PANEL);

  }

  /**

   * Construct.

   *

   * @param id

   */

  public FormComponentPanel(String id)

  {

    super(id);

  }

  /**

   * Construct.

   *

   * @param id

   * @param model

   */

  public FormComponentPanel(String id, IModel<T> model)

  {

    super(id, model);

  }

  /**

   * {@inheritDoc}

   */

  @Override

  public boolean checkRequired()

  {

    return true;

  }

  /**

   * {@inheritDoc}

   */

  @Override

  protected IMarkupSourcingStrategy newMarkupSourcingStrategy()

  {

    return new PanelMarkupSourcingStrategy();

  }

  /**

   * {@inheritDoc}

   */

  @Override

  protected void onComponentTag(final ComponentTag tag)

  {

    super.onComponentTag(tag);

    // remove unapplicable attributes that might have been set by the call to super

    tag.remove("name");

    tag.remove("disabled");

  }

}