guru.mmp.application.web.behaviors.DefaultFocusBehavior.java Source code

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Here is the source code for guru.mmp.application.web.behaviors.DefaultFocusBehavior.java

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/*
 * Copyright 2017 Marcus Portmann
 *
 * Licensed 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 guru.mmp.application.web.behaviors;

//~--- non-JDK imports --------------------------------------------------------

import org.apache.wicket.Component;
import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.markup.head.IHeaderResponse;
import org.apache.wicket.markup.head.OnLoadHeaderItem;

/**
 * The <code>DefaultFocusBehavior</code> class implements the Wicket behavior that sets the focus
 * to the control that is assigned the behavior on page load.
 *
 * @author Marcus Portmann
 */
public class DefaultFocusBehavior extends Behavior {
    private static final long serialVersionUID = 1000000;

    /**
     * Bind this handler to the given component.
     * <p/>
     * This method is called by the host component immediately after this behavior is added to it.
     * This method is useful if you need to do initialisation based on the component it is attached
     * and you can't wait to do it at render time. Keep in mind that if you decide to keep a
     * reference to the host component, it is not thread safe anymore, and should thus only be
     * used in situations where you do not reuse the behavior for multiple components.
     *
     * @param component the component to bind the behavior to
     */
    @Override
    public void bind(Component component) {
        component.setOutputMarkupId(true);
    }

    /**
     * Render to the web response whatever the component wants to contribute to the head section.
     *
     * @param component the component
     * @param response  the header response
     */
    @Override
    public void renderHead(Component component, IHeaderResponse response) {
        super.renderHead(component, response);

        response.render(OnLoadHeaderItem
                .forScript(String.format("document.getElementById('%s').focus();", component.getMarkupId())));
    }
}