com.dotosoft.dot4command.config.xml.ConfigDefineRule.java Source code

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Here is the source code for com.dotosoft.dot4command.config.xml.ConfigDefineRule.java

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/*
   Copyright 2015 Denis Prasetio
       
   Licensed 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 com.dotosoft.dot4command.config.xml;

import org.apache.commons.digester3.Rule;
import org.xml.sax.Attributes;

/**
 * <p>Digester rule that will dynamically register a new set of rules
 * for a specified element name and default implementation class.  This
 * allows "alias" elements to be created for {@link com.dotosoft.dot4command.chain.Chain}
 * and {@link com.dotosoft.dot4command.chain.Command}
 * implementation classes that are commonly used.  Besides factoring out
 * the class names to make changes easier, this also makes configuration
 * files <strong>much</strong> easier to read and write.</p>
 *
 * @version $Id: ConfigDefineRule.java 1363305 2012-07-19 11:42:53Z simonetripodi $
 */
class ConfigDefineRule extends Rule {

    // ----------------------------------------------------------- Constructors

    /**
     * <p>Construct a new instance of this rule that will in turn
     * dynamically register appropriate rules for a new alias element.</p>
     *
     * @param nameAttribute Name of the attribute containing the name
     *  of the new element for which rules should generated
     * @param classAttribute Name of the attribute containing the
     *  implementation class for the new chain or command
     */
    public ConfigDefineRule(String nameAttribute, String classAttribute) {
        super();
        this.nameAttribute = nameAttribute;
        this.classAttribute = classAttribute;
    }

    // ----------------------------------------------------- Instance Variables

    /**
     * <p>The name of the attribute under which we can retrieve the
     * fully qualified class name of the implementation class for this
     * new element.</p>
     */
    private final String classAttribute;

    /**
     * <p>The name of the attribute under which we can retrieve the name
     * this element for which rules should be created.</p>
     */
    private final String nameAttribute;

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

    /**
     * <p>Register new rules for the specified name and class.</p>
     *
     * @param namespace the namespace URI of the matching element, or an
     *   empty string if the parser is not namespace aware or the element has
     *   no namespace
     * @param name the local name if the parser is namespace aware, or just
     *   the element name otherwise
     * @param attributes The attribute list of this element
     */
    public void begin(String namespace, String name, Attributes attributes) throws Exception {
        // Extract the actual name and implementation class to use
        String nameValue = attributes.getValue(nameAttribute);
        String classValue = attributes.getValue(classAttribute);

        // Add rules for this new element
        getDigester().addObjectCreate("*/" + nameValue, classValue);
        getDigester().addSetProperties("*/" + nameValue);
        getDigester().addRule("*/" + nameValue, new ConfigRegisterRule(nameAttribute));
    }

}