Package org.apache.wicket.markup.html.form

Source Code of org.apache.wicket.markup.html.form.FormComponentPanel

/*
* 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.
*/
package org.apache.wicket.markup.html.form;

import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.html.ContainerWithAssociatedMarkupHelper;
import org.apache.wicket.markup.html.HeaderPartContainer;
import org.apache.wicket.markup.html.IHeaderPartContainerProvider;
import org.apache.wicket.markup.html.internal.HtmlHeaderContainer;
import org.apache.wicket.markup.parser.XmlTag;
import org.apache.wicket.model.IModel;

/**
* 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
*/
public abstract class FormComponentPanel extends FormComponent
    implements
      IHeaderPartContainerProvider
{
  private static final long serialVersionUID = 1L;

  private ContainerWithAssociatedMarkupHelper markupHelper;

  /** If if tag was an open-close tag */
  private boolean wasOpenCloseTag = false;

  /**
   * Construct.
   *
   * @param id
   */
  public FormComponentPanel(String id)
  {
    super(id);
  }

  /**
   * Construct.
   *
   * @param id
   * @param model
   */
  public FormComponentPanel(String id, IModel model)
  {
    super(id, model);
  }

  /**
   * @see org.apache.wicket.markup.html.form.FormComponent#checkRequired()
   */
  public boolean checkRequired()
  {
    return true;
  }

  /**
   * @see org.apache.wicket.markup.html.IHeaderPartContainerProvider#newHeaderPartContainer(java.lang.String,
   *      java.lang.String)
   */
  public HeaderPartContainer newHeaderPartContainer(final String id, final String scope)
  {
    return new HeaderPartContainer(id, this, scope);
  }

  /**
   * Check the associated markup file for a wicket header tag
   *
   * @see org.apache.wicket.Component#renderHead(org.apache.wicket.markup.html.internal.HtmlHeaderContainer)
   */
  public void renderHead(HtmlHeaderContainer container)
  {
    if (markupHelper == null)
    {
      markupHelper = new ContainerWithAssociatedMarkupHelper(this);
    }

    markupHelper.renderHeadFromAssociatedMarkupFile(container);

    super.renderHead(container);
  }

  /**
   *
   * @see org.apache.wicket.Component#onComponentTag(org.apache.wicket.markup.ComponentTag)
   */
  protected void onComponentTag(final ComponentTag tag)
  {
    if (tag.isOpenClose())
    {
      wasOpenCloseTag = true;

      // Convert <span wicket:id="myPanel" /> into
      // <span wicket:id="myPanel">...</span>
      tag.setType(XmlTag.OPEN);
    }
    super.onComponentTag(tag);
  }

  /**
   *
   * @see org.apache.wicket.Component#onComponentTagBody(org.apache.wicket.markup.MarkupStream,
   *      org.apache.wicket.markup.ComponentTag)
   */
  protected void onComponentTagBody(final MarkupStream markupStream, final ComponentTag openTag)
  {
    // Render the associated markup
    renderAssociatedMarkup("panel",
        "Markup for a panel component has to contain part '<wicket:panel>'");

    if (wasOpenCloseTag == false)
    {
      // Skip any raw markup in the body
      markupStream.skipRawMarkup();
    }
  }
}
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