servlettoolboxruleset.java

一个用于java web页面开发的开源包

package org.apache.velocity.tools.view.servlet;

/*
 * 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.
 */

import org.apache.commons.digester.Digester;
import org.apache.commons.digester.Rule;
import org.apache.velocity.tools.view.ToolboxRuleSet;

/**
 * <p>The set of Digester rules required to parse a toolbox
 * configuration file (<code>toolbox.xml</code>) for the
 * ServletToolboxManager class.</p>
 *
 * @since VelocityTools 1.1
 * @author Nathan Bubna
 * @version $Id: ServletToolboxRuleSet.java 479724 2006-11-27 18:49:37Z nbubna $
 */
public class ServletToolboxRuleSet extends ToolboxRuleSet
{

    /**
     * Overrides {@link ToolboxRuleSet} to add create-session rule.
     *
     * <p>These rules assume that an instance of
     * <code>org.apache.velocity.tools.view.ServletToolboxManager</code> is
     * pushed onto the evaluation stack before parsing begins.</p>
     *
     * @param digester Digester instance to which the new Rule instances
     *  should be added.
     */
    public void addRuleInstances(Digester digester)
    {
        digester.addRule("toolbox/create-session", new CreateSessionRule());
        digester.addRule("toolbox/xhtml", new XhtmlRule());
        super.addRuleInstances(digester);
    }


    /**
     * Overrides {@link ToolboxRuleSet} to add rule for scope element.
     */
    protected void addToolRules(Digester digester)
    {
        super.addToolRules(digester);
        digester.addBeanPropertySetter("toolbox/tool/scope", "scope");
        digester.addBeanPropertySetter("toolbox/tool/request-path", "requestPath");
    }


    /**
     * Overrides {@link ToolboxRuleSet} to use ServletToolInfo class.
     */
    protected Class getToolInfoClass()
    {
        return ServletToolInfo.class;
    }


    /****************************** Custom Rules *****************************/

    /**
     * Abstract rule for configuring boolean options on the parent
     * object/element of the matching element.
     */
    protected abstract class BooleanConfigRule extends Rule
    {
        public void body(String ns, String name, String text) throws Exception
        {
            Object parent = digester.peek();
            if ("yes".equalsIgnoreCase(text))
            {
                setBoolean(parent, Boolean.TRUE);
            }
            else
            {
                setBoolean(parent, Boolean.valueOf(text));
            }
        }

        /**
         * Takes the parent object and boolean value in order to
         * call the appropriate method on the parent for the
         * implementing rule.
         *
         * @param parent the parent object/element in the digester's stack
         * @param value the boolean value contained in the current element
         */
        public abstract void setBoolean(Object parent, Boolean value)
            throws Exception;
    }


    /**
     * Rule that sets <code>setCreateSession()</code> for the top object
     * on the stack, which must be a
     * <code>org.apache.velocity.tools.ServletToolboxManager</code>.
     */
    protected final class CreateSessionRule extends BooleanConfigRule
    {
        public void setBoolean(Object obj, Boolean b) throws Exception
        {
            ((ServletToolboxManager)obj).setCreateSession(b.booleanValue());
        }
    }


    /**
     * Rule that sets <code>setXhtml()</code> for the top object
     * on the stack, which must be a
     * <code>org.apache.velocity.tools.ServletToolboxManager</code>.
     */
    protected final class XhtmlRule extends BooleanConfigRule
    {
        public void setBoolean(Object obj, Boolean b) throws Exception
        {
            ((ServletToolboxManager)obj).setXhtml(b);
        }
    }

}