cvs commit: jakarta-commons/chain/src/java/org/apache/commons/chain/config ConfigCatalogRule.java

[cr...@apache.org]

craigmcc    2004/10/18 11:47:12

  Added:       chain/src/java/org/apache/commons/chain/config
                        ConfigCatalogRule.java
  Log:
  Add forgotten new class.
  
  Revision  Changes    Path
  1.1                  jakarta-commons/chain/src/java/org/apache/commons/chain/config/ConfigCatalogRule.java
  
  Index: ConfigCatalogRule.java
  ===================================================================
  /*
   * Copyright 1999-2004 The Apache Software Foundation
   *
   * 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 org.apache.commons.chain.config;
  
  
  import org.apache.commons.chain.Catalog;
  import org.apache.commons.chain.CatalogFactory;
  import org.apache.commons.chain.Chain;
  import org.apache.commons.chain.Command;
  import org.apache.commons.digester.Rule;
  import org.xml.sax.Attributes;
  
  
  /**
   * <p>Digester rule that will cause the top-most element on the Digester
   * stack (if it is a {@link Catalog} to be registered with the
   * {@link CatalogFactory} instance for our application.  If the attribute
   * specified to our constructor has a value, that will be used as the name
   * under which to register this {@link Catalog}.  Otherwise, this will
   * become the default {@link Catalog} for this application.</p>
   *
   * @author Craig R. McClanahan
   * @version $Revision: 1.1 $ $Date: 2004/10/18 18:47:12 $
   */
  class ConfigCatalogRule extends Rule {
  
  
      // ----------------------------------------------------------- Constructors
  
  
      /**
       * <p>Construct a new instance of this rule that looks for an attribute
       * with the specified name.</p>
       *
       * @param nameAttribute Name of the attribute containing the name under
       *  which this command should be registered
       * @param catalogClass Name of the implementation class for newly
       *  created {@link Catalog} instances
       */
      public ConfigCatalogRule(String nameAttribute, String catalogClass) {
          super();
          this.nameAttribute = nameAttribute;
          this.catalogClass = catalogClass;
      }
  
  
      // ----------------------------------------------------- Instance Variables
  
  
      /**
       * <p>The fully qualified class name of a {@link Catalog} class to use for
       * instantiating new instances.</p>
       */
      private String catalogClass = null;
  
  
      /**
       * <p>The name of the attribute under which we can retrieve the name
       * this catalog should be registered with (if any).</p>
       */
      private String nameAttribute = null;
  
  
      // --------------------------------------------------------- Public Methods
  
  
      /**
       * <p>Retrieve or create a {@link Catalog} with the name specified by
       * the <code>nameAttribute</code> attribute, or the default {@link Catalog}
       * if there is no such attribute defined.  Push it onto the top of the
       * stack.</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 {
  
          // Retrieve any current Catalog with the specified name
          Catalog catalog = null;
          CatalogFactory factory = CatalogFactory.getInstance();
          String nameValue = attributes.getValue(nameAttribute);
          if (nameValue == null) {
              catalog = factory.getCatalog();
          } else {
              catalog = factory.getCatalog(nameValue);
          }
  
          // Create and register a new Catalog instance if necessary
          if (catalog == null) {
              Class clazz = digester.getClassLoader().loadClass(catalogClass);
              catalog = (Catalog) clazz.newInstance();
              if (nameValue == null) {
                  factory.setCatalog(catalog);
              } else {
                  factory.addCatalog(nameValue, catalog);
              }
          }
  
          // Push this Catalog onto the top of the stack
          digester.push(catalog);
  
      }
  
  
  }
  
  
  

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