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

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Here is the source code for org.apache.wicket.markup.html.form.FormComponentLabel.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.core.util.string.CssUtils;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.markup.parser.XmlTag.TagType;
import org.apache.wicket.util.lang.Args;

/**
 * A component that represents HTML <label> tag. This component will automatically make the
 * form component output an <em>id</em> attribute and link its <em>for</em> attribute with that
 * value.
 * 
 * @author Igor Vaynberg (ivaynberg)
 */
public class FormComponentLabel extends WebMarkupContainer {
    private static final long serialVersionUID = 1L;

    public static final String REQUIRED_CSS_CLASS_KEY = CssUtils.key(FormComponentLabel.class, "required");

    public static final String INVALID_CSS_CLASS_KEY = CssUtils.key(FormComponentLabel.class, "invalid");

    public static final String DISABLED_CSS_CLASS_KEY = CssUtils.key(FormComponentLabel.class, "disabled");

    private final LabeledWebMarkupContainer component;

    /**
     * Constructor
     * 
     * @param id
     *            component id
     * @param component
     *            component that this label is linked to
     */
    public FormComponentLabel(String id, LabeledWebMarkupContainer component) {
        super(id);

        this.component = Args.notNull(component, "component");
        component.setOutputMarkupId(true);
    }

    /**
     * 
     * @see org.apache.wicket.Component#onComponentTag(org.apache.wicket.markup.ComponentTag)
     */
    @Override
    protected void onComponentTag(ComponentTag tag) {
        super.onComponentTag(tag);

        checkComponentTag(tag, "label");

        LabeledWebMarkupContainer formComponent = getFormComponent();

        tag.put("for", formComponent.getMarkupId());

        if (formComponent instanceof FormComponent<?>) {
            FormComponent<?> fc = (FormComponent<?>) formComponent;

            if (fc.isRequired()) {
                tag.append("class", getString(REQUIRED_CSS_CLASS_KEY), " ");
            }
            if (fc.isValid() == false) {
                tag.append("class", getString(INVALID_CSS_CLASS_KEY), " ");
            }
        }

        if (formComponent.isEnabledInHierarchy() == false) {
            tag.append("class", getString(DISABLED_CSS_CLASS_KEY), " ");
        }

        // always transform the tag to <span></span> so even labels defined as <span/> render
        tag.setType(TagType.OPEN);
    }

    /**
     * Returns LabeledWebMarkupContainer bound to this label. This will be a FormComponent, a Radio
     * or a Check.
     * 
     * @return form component
     */
    public LabeledWebMarkupContainer getFormComponent() {
        return component;
    }
}