org.apache.wicket.markup.html.panel.Panel.java Source code

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Here is the source code for org.apache.wicket.markup.html.panel.Panel.java

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/*
 * 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.panel;

import org.apache.wicket.IQueueRegion;
import org.apache.wicket.markup.IMarkupFragment;
import org.apache.wicket.markup.html.MarkupUtil;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.model.IModel;

/**
 * A panel is a reusable component that holds markup and other components.
 * <p>
 * Whereas WebMarkupContainer is an inline container like
 * 
 * <pre>
 *  ...
 *  &lt;span wicket:id=&quot;xxx&quot;&gt;
 *    &lt;span wicket:id=&quot;mylabel&quot;&gt;My label&lt;/span&gt;
 *    ....
 *  &lt;/span&gt;
 *  ...
 * </pre>
 * 
 * a Panel has its own associated markup file and the container content is taken from that file,
 * like:
 * 
 * <pre>
 *  &lt;span wicket:id=&quot;mypanel&quot;/&gt;
 * 
 *  TestPanel.html
 *  &lt;wicket:panel&gt;
 *    &lt;span wicket:id=&quot;mylabel&quot;&gt;My label&lt;/span&gt;
 *    ....
 *  &lt;/wicket:panel&gt;
 * </pre>
 * 
 * @author Jonathan Locke
 * @author Juergen Donnerstag
 */
public abstract class Panel extends WebMarkupContainer implements IQueueRegion {
    private static final long serialVersionUID = 1L;

    /** */
    public static final String PANEL = "panel";

    /**
     * @see org.apache.wicket.Component#Component(String)
     */
    public Panel(final String id) {
        super(id);
    }

    /**
     * @see org.apache.wicket.Component#Component(String, IModel)
     */
    public Panel(final String id, final IModel<?> model) {
        super(id, model);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected IMarkupSourcingStrategy newMarkupSourcingStrategy() {
        return new PanelMarkupSourcingStrategy(false);
    }

    /**
     * Returns the markup inside &lt;wicket:panel&gt; tag.
     * If such tag is not found, all the markup is returned.
     * 
     * @see IQueueRegion#getRegionMarkup() 
     */
    @Override
    public IMarkupFragment getRegionMarkup() {
        IMarkupFragment markup = super.getRegionMarkup();

        if (markup == null) {
            return markup;
        }

        IMarkupFragment panelMarkup = MarkupUtil.findStartTag(markup, PANEL);

        return panelMarkup != null ? panelMarkup : markup;
    }
}