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

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Here is the source code for org.apache.wicket.markup.html.form.Radio.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.Component;
import org.apache.wicket.IGenericComponent;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.model.IModel;

/**
 * Component representing a single radio choice in a org.apache.wicket.markup.html.form.RadioGroup.
 * 
 * Must be attached to an <input type="radio" ... > markup.
 * <p>
 * STATELESS NOTES: By default this component cannot be used inside a stateless form. If it is
 * desirable to use this inside a stateless form then
 * <ul>
 * <li>
 * override #getValue() and return some stateless value to uniquely identify this radio (eg relative
 * component path from group to this radio)</li>
 * <li>
 * override {@link #getStatelessHint()} and return <code>true</code></li>
 * </ul>
 * </p>
 * 
 * @see org.apache.wicket.markup.html.form.RadioGroup
 * 
 * @author Igor Vaynberg
 * @author Sven Meier (svenmeier)
 * 
 * @param <T>
 *            The model object type
 */
public class Radio<T> extends LabeledWebMarkupContainer implements IGenericComponent<T, Radio<T>> {
    private static final long serialVersionUID = 1L;

    private static final String ATTR_DISABLED = "disabled";

    /**
     * page-scoped uuid of this check. this property must not be accessed directly, instead
     * {@link #getValue()} must be used
     */
    private int uuid = -1;

    private final RadioGroup<T> group;

    /**
     * @see WebMarkupContainer#WebMarkupContainer(String)
     */
    public Radio(final String id) {
        this(id, null, null);
    }

    /**
     * @param id
     * @param model
     * @see WebMarkupContainer#WebMarkupContainer(String, IModel)
     */
    public Radio(final String id, final IModel<T> model) {
        this(id, model, null);
    }

    /**
     * @param id
     * @param group
     *            parent {@link RadioGroup}
     * @see WebMarkupContainer#WebMarkupContainer(String)
     */
    public Radio(final String id, final RadioGroup<T> group) {
        this(id, null, group);
    }

    /**
     * @param id
     * @param model
     * @param group
     *            parent {@link RadioGroup}
     * @see WebMarkupContainer#WebMarkupContainer(String, IModel)
     */
    public Radio(final String id, final IModel<T> model, final RadioGroup<T> group) {
        super(id, model);
        this.group = group;
        setOutputMarkupId(true);
    }

    /**
     * Form submission value used for the Html <code>value</code> attribute of the <code>input</code> tag.
     * <p>
     * If {@link Radio}s are recreated on each render of their {@link RadioGroup}, this method should
     * be overridden to return a 'stable' value, otherwise its selection will be lost after a {@link Form}
     * was submitted and resulted in {@link Form#hasError()}.
     * 
     * @return input value
     */
    public String getValue() {
        if (uuid < 0) {
            uuid = getPage().getAutoIndex();
        }
        return "radio" + uuid;
    }

    /**
     * 
     * @return The associated radio group Component
     */
    @SuppressWarnings("unchecked")
    protected RadioGroup<T> getGroup() {
        RadioGroup<T> group = this.group;
        if (group == null) {
            group = findParent(RadioGroup.class);
            if (group == null) {
                throw new WicketRuntimeException("Radio component [" + getPath()
                        + "] cannot find its parent RadioGroup. All Radio components must be a child of or below in the hierarchy of a RadioGroup component.");
            }
        }
        return group;
    }

    /**
     * @see Component#onComponentTag(ComponentTag)
     * @param tag
     *            the abstraction representing html tag of this component
     */
    @Override
    protected void onComponentTag(final ComponentTag tag) {
        // Default handling for component tag
        super.onComponentTag(tag);

        // must be attached to <input type="radio" .../> tag
        checkComponentTag(tag, "input");
        checkComponentTagAttribute(tag, "type", "radio");

        final String value = getValue();

        RadioGroup<?> group = getGroup();

        // assign name and value
        tag.put("name", group.getInputName());
        tag.put("value", value);

        // compare the model objects of the group and self, if the same add the
        // checked attribute, first check if there was a raw input on the group.
        if (group.hasRawInput()) {
            String rawInput = group.getRawInput();
            if (rawInput != null && rawInput.equals(value)) {
                tag.put("checked", "checked");
            }
        } else if (group.getModelComparator().compare(group, getDefaultModelObject())) {
            tag.put("checked", "checked");
        }

        if (!isEnabledInHierarchy()) {
            tag.put(ATTR_DISABLED, ATTR_DISABLED);
        }

    }

    /**
     * The value will be made available to the validator property by means of ${label}. It does not
     * have any specific meaning to Radio itself.
     * 
     * @param labelModel
     * @return this for chaining
     */
    @Override
    public Radio<T> setLabel(IModel<String> labelModel) {
        super.setLabel(labelModel);
        return this;
    }

    /** {@inheritDoc} */
    @Override
    protected boolean getStatelessHint() {
        // because we keep uuid this component cannot be stateless
        return false;
    }
}