| // Copyright 2004 The Apache Software Foundation |
| // |
| // 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 org.apache.tapestry.form; |
| |
| import org.apache.tapestry.AbstractComponent; |
| import org.apache.tapestry.ApplicationRuntimeException; |
| import org.apache.tapestry.IMarkupWriter; |
| import org.apache.tapestry.IRequestCycle; |
| import org.apache.tapestry.Tapestry; |
| |
| /** |
| * Implements a component that manages an HTML <input type=radio> form element. |
| * Such a component must be wrapped (possibly indirectly) |
| * inside a {@link RadioGroup} component. |
| * |
| * [<a href="../../../../../ComponentReference/Radio.html">Component Reference</a>] |
| * |
| * |
| * <p>{@link Radio} and {@link RadioGroup} are generally not used (except |
| * for very special cases). Instead, a {@link PropertySelection} component is used. |
| * |
| * |
| * @author Howard Lewis Ship |
| * @version $Id$ |
| * |
| **/ |
| |
| public abstract class Radio extends AbstractComponent |
| { |
| /** |
| * Renders the form element, or responds when the form containing the element |
| * is submitted (by checking {@link Form#isRewinding()}. |
| * |
| * |
| **/ |
| |
| protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle) |
| { |
| |
| RadioGroup group = RadioGroup.get(cycle); |
| if (group == null) |
| throw new ApplicationRuntimeException( |
| Tapestry.getMessage("Radio.must-be-contained-by-group"), |
| this, |
| null, |
| null); |
| |
| // The group determines rewinding from the form. |
| |
| boolean rewinding = group.isRewinding(); |
| |
| int option = group.getNextOptionId(); |
| |
| if (rewinding) |
| { |
| // If not disabled and this is the selected button within the radio group, |
| // then update set the selection from the group to the value for this |
| // radio button. This will update the selected parameter of the RadioGroup. |
| |
| if (!isDisabled() && !group.isDisabled() && group.isSelected(option)) |
| group.updateSelection(getValue()); |
| return; |
| } |
| |
| writer.beginEmpty("input"); |
| |
| writer.attribute("type", "radio"); |
| |
| writer.attribute("name", group.getName()); |
| |
| // As the group if the value for this Radio matches the selection |
| // for the group as a whole; if so this is the default radio and is checked. |
| |
| if (group.isSelection(getValue())) |
| writer.attribute("checked", "checked"); |
| |
| if (isDisabled() || group.isDisabled()) |
| writer.attribute("disabled", "disabled"); |
| |
| // The value for the Radio matches the option number (provided by the RadioGroup). |
| // When the form is submitted, the RadioGroup will know which option was, |
| // in fact, selected by the user. |
| |
| writer.attribute("value", option); |
| |
| renderInformalParameters(writer, cycle); |
| |
| } |
| |
| public abstract boolean isDisabled(); |
| |
| public abstract Object getValue(); |
| } |