/*
* 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.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 Command} to be registered with the next-to-top
* element on the Digester stack (if it is a {@link Catalog} or {@link Chain}).
* To be registered with a {@link Catalog}, the top-most element must contain
* a value for the specified attribute that contains the name under which
* it should be registered.</p>
*
* @author Craig R. McClanahan
* @version $Revision: 1.5 $ $Date: 2004/11/30 05:52:23 $
*/
class ConfigRegisterRule 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
*/
public ConfigRegisterRule(String nameAttribute) {
super();
this.nameAttribute = nameAttribute;
}
// ----------------------------------------------------- Instance Variables
/**
* <p>The name of the attribute under which we can retrieve the name
* this command should be registered with.</p>
*/
private String nameAttribute = null;
// --------------------------------------------------------- Public Methods
/**
* <p>Register the top {@link Command} if appropriate.</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 {
// Is the top object a Command?
Object top = digester.peek(0);
if ((top == null)
|| !(top instanceof Command)) {
return;
}
Command command = (Command) top;
// Is the next object a Catalog or a Chain?
Object next = digester.peek(1);
if (next == null) {
return;
}
// Register the top element appropriately
if (next instanceof Catalog) {
Catalog catalog = (Catalog) next;
String nameValue = attributes.getValue(nameAttribute);
if (nameValue != null) {
((Catalog) next).addCommand(nameValue, command);
}
} else if (next instanceof Chain) {
((Chain) next).addCommand(command);
}
}
}