ParentResolver.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.markup.ComponentTag;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.WicketTag;

/**
 * Some containers are transparent to the user (e.g. HtmlHeaderContainer or BodyOnLoadContainer) and
 * delegate component resolution to there parent.
 * 
 * @author Juergen Donnerstag
 */
public class ParentResolver implements IComponentResolver
{
  private static final long serialVersionUID = 1L;

  /**
   * Try to resolve the tag, then create a component, add it to the container and render it.
   * <p>
   * Note: Special tags like &ltwicket:...&gt> and tags which id start with "_" are not resolved.
   * 
   * @see org.apache.wicket.markup.resolver.IComponentResolver#resolve(MarkupContainer,
   *      MarkupStream, ComponentTag)
   */
  public boolean resolve(final MarkupContainer container, final MarkupStream markupStream,
    final ComponentTag tag)
  {
    // Ignore special tags like _panel, _border, _extend etc.
    if ((tag instanceof WicketTag) || tag.isAutoComponentTag())
    {
      return false;
    }

    MarkupContainer parent = container;
    while ((parent != null) && (parent.isTransparentResolver()))
    {
      // Try to find the component with the parent component.
      parent = parent.getParent();
      if (parent != null)
      {
        Component component = parent.get(tag.getId());
        if (component != null)
        {
          component.render(markupStream);
          return true;
        }
      }
    }

    // If not yet found, restore the original parent and test if it
    // implement IComponentResolver
    parent = container.getParent();
    if (parent instanceof IComponentResolver)
    {
      return ((IComponentResolver)parent).resolve(container, markupStream, tag);
    }
    return false;
  }
}