tapestry/tapestry-framework/src/java/org/apache/tapestry/util/xml/IRule.java

// Copyright 2004, 2005 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.tapestry.util.xml;

import org.xml.sax.Attributes;

/**
 * A rule that may be pushed onto the
 * {@link org.apache.tapestry.util.xml.RuleDirectedParser}'s rule stack. A rule
 * is associated with an XML element. It is pushed onto the stack when the open
 * tag for the rule is encountered. It is is popped off the stack after the
 * end-tag is encountered. It is notified about any text it directly wraps
 * around.
 * <p>
 * Rules should be stateless, because a rule instance may appear multiple times
 * in the rule stack (if elements can be recusively nested).
 * 
 * @author Howard Lewis Ship
 * @since 3.0
 */

public interface IRule
{

    /**
     * Invoked just after the rule is pushed onto the rule stack. Typically, a
     * Rule will use the information to create a new object and push it onto the
     * object stack. If the rule needs to know about the element (rather than
     * the attributes), it may obtain the URI, localName and qName from the
     * parser.
     */
    void startElement(RuleDirectedParser parser, Attributes attributes);

    /**
     * Invoked just after the rule is popped off the rule stack.
     */
    void endElement(RuleDirectedParser parser);

    /**
     * Invoked when real content is found. The parser is responsible for
     * aggregating all content provided by the underlying SAX parser into a
     * single string.
     */

    void content(RuleDirectedParser parser, String content);
}