checkboxtag.java

structs源码

/*
 * $Id: CheckboxTag.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 "checkbox".
 *
 * @version $Rev: 471754 $ $Date: 2004-10-16 12:38:42 -0400 (Sat, 16 Oct 2004)
 *          $
 */
public class CheckboxTag 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;

    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 (value == null) ? "on" : value;
    }

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

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

    /**
     * Generate the required input tag. <p> Support for indexed property since
     * Struts 1.1
     *
     * @throws JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {
        // Create an appropriate "input" element based on our parameters
        StringBuffer results = new StringBuffer("<input type=\"checkbox\"");

        prepareAttribute(results, "name", prepareName());
        prepareAttribute(results, "accesskey", getAccesskey());
        prepareAttribute(results, "tabindex", getTabindex());

        prepareAttribute(results, "value", getValue());

        if (isChecked()) {
            results.append(" checked=\"checked\"");
        }

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

        // Print this field to our output writer
        TagUtils.getInstance().write(pageContext, results.toString());

        // Continue processing this page
        this.text = null;

        return (EVAL_BODY_TAG);
    }

    /**
     * Determines if the checkbox should be checked.
     *
     * @return true if checked="checked" should be rendered.
     * @throws JspException
     * @since Struts 1.2
     */
    protected boolean isChecked()
        throws JspException {
        Object result =
            TagUtils.getInstance().lookup(pageContext, name, property, null);

        if (result == null) {
            result = "";
        }

        result = result.toString();

        String checked = (String) result;

        return (checked.equalsIgnoreCase(this.value)
        || checked.equalsIgnoreCase("true") || checked.equalsIgnoreCase("yes")
        || checked.equalsIgnoreCase("on"));
    }

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

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

        return (SKIP_BODY);
    }

    /**
     * Process the remainder of this page normally.
     *
     * @throws JspException if a JSP exception has occurred
     */
    public int doEndTag() throws JspException {
        // Render any description for this checkbox
        if (text != null) {
            TagUtils.getInstance().write(pageContext, text);
        }

        // Evaluate the remainder of this page
        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();
        name = Constants.BEAN_KEY;
        property = null;
        text = null;
        value = null;
    }
}