org.apache.wicket.markup.html.form.FormComponentPanel.java Source code

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Here is the source code for org.apache.wicket.markup.html.form.FormComponentPanel.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.form;

import org.apache.wicket.IQueueRegion;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.panel.IMarkupSourcingStrategy;
import org.apache.wicket.markup.html.panel.PanelMarkupSourcingStrategy;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.visit.IVisitor;

/**
 * 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.
 * </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
 */
public abstract class FormComponentPanel<T> extends FormComponent<T> implements IQueueRegion {
    private static final long serialVersionUID = 1L;

    /**
     * Constructor.
     * 
     * @param id
     *          The component id
     */
    public FormComponentPanel(String id) {
        super(id);
    }

    /**
     * Constructor.
     * 
     * @param id
     *          The component id
     * @param model
     *          The component model
     */
    public FormComponentPanel(String id, IModel<T> model) {
        super(id, model);
    }

    @Override
    public boolean checkRequired() {
        return true;
    }

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

    @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");
    }

    @Override
    public void clearInput() {
        super.clearInput();

        // Visit all the (visible) form components and clear the input on each.
        visitFormComponentsPostOrder(this, (IVisitor<FormComponent<?>, Void>) (formComponent, visit) -> {
            if (formComponent != FormComponentPanel.this && formComponent.isVisibleInHierarchy()) {
                formComponent.clearInput();
            }
        });
    }
}