radiotag.java

structs源码

/*
 * $Id: RadioTag.java 471754 2006-11-06 14:55:09Z husted $
 *
 * 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.struts.taglib.html;

import org.apache.struts.taglib.TagUtils;
import org.apache.struts.util.MessageResources;

import javax.servlet.jsp.JspException;

/**
 * Tag for input fields of type "radio".
 *
 * @version $Rev: 471754 $ $Date: 2005-06-14 14:26:17 -0400 (Tue, 14 Jun 2005)
 *          $
 */
public class RadioTag extends BaseHandlerTag {
    // ----------------------------------------------------- Instance Variables

    /**
     * The message resources for this package.
     */
    protected static MessageResources messages =
        MessageResources.getMessageResources(Constants.Package
            + ".LocalStrings");

    /**
     * The name of the bean containing our underlying property.
     */
    protected String name = Constants.BEAN_KEY;

    /**
     * The property name for this field.
     */
    protected String property = null;

    /**
     * The body content of this tag (if any).
     */
    protected String text = null;

    /**
     * The server value for this option.
     */
    protected String value = null;

    /**
     * Name of the bean (in some scope) that will return the value of the
     * radio tag. <p> If an iterator is used to render a series of radio tags,
     * this field may be used to specify the name of the bean exposed by the
     * iterator. In this case, the value attribute is used as the name of a
     * property on the <code>idName</code> bean that returns the value of the
     * radio tag in this iteration.
     */
    protected String idName = null;

    public String getName() {
        return (this.name);
    }

    public void setName(String name) {
        this.name = name;
    }

    // ------------------------------------------------------------- Properties

    /**
     * Return the property name.
     */
    public String getProperty() {
        return (this.property);
    }

    /**
     * Set the property name.
     *
     * @param property The new property name
     */
    public void setProperty(String property) {
        this.property = property;
    }

    /**
     * Return the server value.
     */
    public String getValue() {
        return (this.value);
    }

    /**
     * Set the server value.
     *
     * @param value The new server value
     */
    public void setValue(String value) {
        this.value = value;
    }

    /**
     * Return the idName.
     *
     * @since Struts 1.1
     */
    public String getIdName() {
        return (this.idName);
    }

    /**
     * Set the idName.
     *
     * @param idName The new idName
     * @since Struts 1.1
     */
    public void setIdName(String idName) {
        this.idName = idName;
    }

    // --------------------------------------------------------- Public Methods

    /**
     * Generate the required input tag. [Indexed property since Struts 1.1]
     *
     * @throws JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {
        String radioTag = renderRadioElement(serverValue(), currentValue());

        TagUtils.getInstance().write(pageContext, radioTag);

        this.text = null;

        return (EVAL_BODY_TAG);
    }

    /**
     * Return the String to be used in the radio tag's <code>value</code>
     * attribute that gets sent to the server on form submission.
     *
     * @throws JspException
     */
    private String serverValue()
        throws JspException {
        // Not using indexed radio buttons
        if (this.idName == null) {
            return this.value;
        }

        String serverValue = this.lookupProperty(this.idName, this.value);

        return (serverValue == null) ? "" : serverValue;
    }

    /**
     * Acquire the current value of the bean specified by the
     * <code>name</code> attribute and the property specified by the
     * <code>property</code> attribute. This radio button with this value will
     * be checked.
     *
     * @throws JspException
     */
    private String currentValue()
        throws JspException {
        String current = this.lookupProperty(this.name, this.property);

        return (current == null) ? "" : current;
    }

    /**
     * Renders an HTML &lt;input type="radio"&gt; element.
     *
     * @param serverValue  The data to be used in the tag's <code>value</code>
     *                     attribute and sent to the server when the form is
     *                     submitted.
     * @param checkedValue If the serverValue equals this value the radio
     *                     button will be checked.
     * @return A radio input element.
     * @throws JspException
     * @since Struts 1.1
     */
    protected String renderRadioElement(String serverValue, String checkedValue)
        throws JspException {
        StringBuffer results = new StringBuffer("<input type=\"radio\"");

        prepareAttribute(results, "name", prepareName());
        prepareAttribute(results, "accesskey", getAccesskey());
        prepareAttribute(results, "tabindex", getTabindex());
        prepareAttribute(results, "value",
            TagUtils.getInstance().filter(serverValue));

        if (serverValue.equals(checkedValue)) {
            results.append(" checked=\"checked\"");
        }

        results.append(prepareEventHandlers());
        results.append(prepareStyles());
        prepareOtherAttributes(results);
        results.append(getElementClose());

        return results.toString();
    }

    /**
     * Save the associated label from the body content.
     *
     * @throws JspException if a JSP exception has occurred
     */
    public int doAfterBody() throws JspException {
        if (this.bodyContent != null) {
            String value = this.bodyContent.getString().trim();

            if (value.length() > 0) {
                this.text = value;
            }
        }

        return (SKIP_BODY);
    }

    /**
     * Optionally render the associated label from the body content.
     *
     * @throws JspException if a JSP exception has occurred
     */
    public int doEndTag() throws JspException {
        // Render any description for this radio button
        if (this.text != null) {
            TagUtils.getInstance().write(pageContext, text);
        }

        return (EVAL_PAGE);
    }

    /**
     * Prepare the name element
     *
     * @return The element name.
     */
    protected String prepareName()
        throws JspException {
        if (property == null) {
            return null;
        }

        // * @since Struts 1.1
        if (indexed) {
            StringBuffer results = new StringBuffer();

            prepareIndex(results, name);
            results.append(property);

            return results.toString();
        }

        return property;
    }

    /**
     * Release any acquired resources.
     */
    public void release() {
        super.release();
        idName = null;
        name = Constants.BEAN_KEY;
        property = null;
        text = null;
        value = null;
    }
}