001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.wicket.markup.html.form;
018
019import org.apache.wicket.core.util.string.CssUtils;
020import org.apache.wicket.markup.ComponentTag;
021import org.apache.wicket.markup.html.WebMarkupContainer;
022import org.apache.wicket.markup.parser.XmlTag.TagType;
023import org.apache.wicket.util.lang.Args;
024
025/**
026 * A component that represents HTML <label> tag. This component will automatically make the
027 * form component output an <em>id</em> attribute and link its <em>for</em> attribute with that
028 * value.
029 * 
030 * @author Igor Vaynberg (ivaynberg)
031 */
032public class FormComponentLabel extends WebMarkupContainer
033{
034        private static final long serialVersionUID = 1L;
035
036        public static final String REQUIRED_CSS_CLASS_KEY = CssUtils.key(FormComponentLabel.class,
037                        "required");
038
039        public static final String INVALID_CSS_CLASS_KEY = CssUtils.key(FormComponentLabel.class,
040                        "invalid");
041
042        public static final String DISABLED_CSS_CLASS_KEY = CssUtils.key(FormComponentLabel.class,
043                        "disabled");
044
045        private final LabeledWebMarkupContainer component;
046
047        /**
048         * Constructor
049         * 
050         * @param id
051         *            component id
052         * @param component
053         *            component that this label is linked to
054         */
055        public FormComponentLabel(String id, LabeledWebMarkupContainer component)
056        {
057                super(id);
058
059                this.component = Args.notNull(component, "component");
060                component.setOutputMarkupId(true);
061        }
062
063        /**
064         * 
065         * @see org.apache.wicket.Component#onComponentTag(org.apache.wicket.markup.ComponentTag)
066         */
067        @Override
068        protected void onComponentTag(ComponentTag tag)
069        {
070                super.onComponentTag(tag);
071
072                checkComponentTag(tag, "label");
073
074                LabeledWebMarkupContainer formComponent = getFormComponent();
075
076                tag.put("for", formComponent.getMarkupId());
077
078                if (formComponent instanceof FormComponent<?>)
079                {
080                        FormComponent<?> fc = (FormComponent<?>) formComponent;
081
082                        if (fc.isRequired())
083                        {
084                                tag.append("class", getString(REQUIRED_CSS_CLASS_KEY), " ");
085                        }
086                        if (fc.isValid() == false)
087                        {
088                                tag.append("class", getString(INVALID_CSS_CLASS_KEY), " ");
089                        }
090                }
091
092                if (formComponent.isEnabledInHierarchy() == false)
093                {
094                        tag.append("class", getString(DISABLED_CSS_CLASS_KEY), " ");
095                }
096
097                // always transform the tag to <span></span> so even labels defined as <span/> render
098                tag.setType(TagType.OPEN);
099        }
100
101        /**
102         * Returns LabeledWebMarkupContainer bound to this label. This will be a FormComponent, a Radio
103         * or a Check.
104         * 
105         * @return form component
106         */
107        public LabeledWebMarkupContainer getFormComponent()
108        {
109                return component;
110        }
111}