errorstool.java

一个用于java web页面开发的开源包

package org.apache.velocity.tools.struts;

/*
 * 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.
 */

/**
 * <p>View tool to work with the Struts error messages.</p>
 * <p><pre>
 * Template example(s):
 *   #if( $errors.exist() )
 *     &lt;div class="errors"&gt;
 *     #foreach( $e in $errors.all )
 *       $e &lt;br&gt;
 *     #end
 *     &lt;/div&gt;
 *   #end
 *
 * Toolbox configuration:
 * &lt;tool&gt;
 *   &lt;key&gt;errors&lt;/key&gt;
 *   &lt;scope&gt;request&lt;/scope&gt;
 *   &lt;class&gt;org.apache.velocity.tools.struts.ErrorsTool&lt;/class&gt;
 * &lt;/tool&gt;
 * </pre></p>
 *
 * <p>This tool should only be used in the request scope.</p>
 * <p>Since VelocityTools 1.1, ErrorsTool extends ActionMessagesTool.</p>
 *
 * @author <a href="mailto:[e-mail]">Gabe Sidler</a>
 * @author Nathan Bubna
 * @since VelocityTools 1.0
 * @version $Id: ErrorsTool.java 479724 2006-11-27 18:49:37Z nbubna $
 */
public class ErrorsTool extends ActionMessagesTool
{

    /**
     * Initializes this tool.
     *
     * @param obj the current ViewContext
     * @throws IllegalArgumentException if the param is not a ViewContext
     */
    public void init(Object obj)
    {
        //setup superclass instance members
        super.init(obj);

        this.actionMsgs = StrutsUtils.getErrors(this.request);
    }


    /**
     * <p>Renders the queued error messages as a list. This method expects
     * the message keys <code>errors.header</code> and <code>errors.footer</code>
     * in the message resources. The value of the former is rendered before
     * the list of error messages and the value of the latter is rendered
     * after the error messages.</p>
     *
     * @return The formatted error messages. If no error messages are queued,
     * an empty string is returned.
     */
    public String getMsgs()
    {
        return getMsgs(null, null);
    }


    /**
     * <p>Renders the queued error messages of a particual category as a list.
     * This method expects the message keys <code>errors.header</code> and
     * <code>errors.footer</code> in the message resources. The value of the
     * former is rendered before the list of error messages and the value of
     * the latter is rendered after the error messages.</p>
     *
     * @param property the category of errors to render
     *
     * @return The formatted error messages. If no error messages are queued,
     * an empty string is returned.
     */
    public String getMsgs(String property)
    {
        return getMsgs(property, null);
    }


    /**
     * <p>Renders the queued error messages of a particual category as a list.
     * This method expects the message keys <code>errors.header</code> and
     * <code>errors.footer</code> in the message resources. The value of the
     * former is rendered before the list of error messages and the value of
     * the latter is rendered after the error messages.</p>
     *
     * @param property the category of errors to render
     * @param bundle the message resource bundle to use
     *
     * @return The formatted error messages. If no error messages are queued,
     * an empty string is returned.
     * @since VelocityTools 1.1
     */
    public String getMsgs(String property, String bundle)
    {
        return StrutsUtils.errorMarkup(property, bundle, request,
                                       request.getSession(false), application);
    }

}