ScopedComponentResolver.java :  » J2EE » wicket-1.4 » org » apache » wicket » markup » resolver » Java Open Source

/*
 * 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.resolver;

import org.apache.wicket.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.Page;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.IScopedComponent;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.html.panel.Panel;

/**
 * Implement a component resolver which walks up the component tree until a Page or Panel and tries
 * to find a component with a matching wicket id, effectively providing something like scoping for
 * wicket id resolution.
 * <p>
 * Note: This resolver is not activated by default. It has to be added by means of
 * <code>Application.getComponentResolvers().add(new InheritComponentResolver())
 * to be activated.</code>.
 * <p>
 * Example:
 * 
 * <pre>
 * MyPage()
 * {
 *   add(new Label(&quot;hidden-by-cont1&quot;, &quot;hidden&quot;));
 *   add(new Label(&quot;global&quot;, &quot;can be everywhere&quot;)); //the interesting case
 * 
 *   WebMarkupContainer cont1 = new WebMarkupContainer(&quot;cont1&quot;);
 *   add(cont1);
 * 
 *   cont1.add(new Label(&quot;hidden-by-cont1&quot;, &quot;cont1 hides&quot;));
 *   cont1.add(new Label(&quot;same-id&quot;, &quot;cont1 same-id&quot;));
 * 
 *   WebMarkupContainer cont2 = new WebMarkupContainer(&quot;cont2&quot;);
 *   add(cont2);
 * 
 *   cont2.add(new Label(&quot;same-id&quot;, &quot;cont2 same-id&quot;));
 * }
 * </pre>
 * 
 * <pre>
 * HTML:
 * &lt;html&gt;
 * &lt;body&gt;
 *   &lt;span wicket:id=&quot;hidden-by-cont1&quot;&gt;Prints: hidden&lt;/span&gt;
 *   &lt;div wicket:id=&quot;cont1&quot;&gt;
 *     &lt;span wicket:id=&quot;hidden-by-cont1&quot;&gt;Prints: cont1 hides&lt;/span&gt;
 *     &lt;span wicket:id=&quot;same-id&quot;&gt;Prints: cont1 same-id&lt;/span&gt;
 *   &lt;/div&gt;
 * 
 *   &lt;div wicket:id=&quot;cont2&quot;&gt;
 *     &lt;span wicket:id=&quot;global&quot;&gt;Prints: can be everywhere&lt;/span&gt;
 *     &lt;span wicket:id=&quot;same-id&quot;&gt;Prints: cont2 same-id&lt;/span&gt;
 *   &lt;/div&gt;
 * </pre>
 * 
 * So you can use the same ids in the same page. If the containing containers are not in the same
 * hierarchy-line nothing changes. A comp with the same id hides the one of the parent-container
 * with the same id.
 * 
 * @see org.apache.wicket.MarkupContainer#isTransparentResolver()
 * @see org.apache.wicket.markup.resolver.ParentResolver
 * 
 * @author Christian Essl
 * @author Juergen Donnerstag
 */
public class ScopedComponentResolver implements IComponentResolver
{
  private static final long serialVersionUID = 1L;

  /**
   * Construct.
   */
  public ScopedComponentResolver()
  {
    super();
  }

  /**
   * 
   * @see org.apache.wicket.markup.resolver.IComponentResolver#resolve(org.apache.wicket.MarkupContainer,
   *      org.apache.wicket.markup.MarkupStream, org.apache.wicket.markup.ComponentTag)
   */
  public boolean resolve(final MarkupContainer container, final MarkupStream markupStream,
    final ComponentTag tag)
  {
    // Try to find the component with the parent component.
    final String id = tag.getId();
    MarkupContainer parent = container;

    while (!(parent instanceof Page) && !(parent instanceof Panel) && (parent != null))
    {
      parent = parent.getParent();
      if (parent == null)
      {
        return false;
      }

      final Component component = parent.get(id);
      if ((component != null) && (component instanceof IScopedComponent))
      {
        IScopedComponent sc = (IScopedComponent)component;
        if (sc.isRenderableInSubContainers())
        {
          component.render(markupStream);
          return true;
        }
      }
    }

    return false;
  }
}