001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.services;
016    
017    import org.apache.tapestry.spec.IComponentSpecification;
018    
019    /**
020     * <code>tapestry.enhance.ComponentConstructorFactory</code> service that acts as a wrapper around
021     * {@link org.apache.tapestry.enhance.EnhancementOperation}, used to take a base component class
022     * and provide an enhanced subclass of it.
023     * 
024     * @author Howard M. Lewis Ship
025     * @since 4.0
026     */
027    public interface ComponentConstructorFactory
028    {
029        /**
030         * Passed a component specification and the base component class name, provides back an object
031         * used to instantiate instances of the component. {@link ComponentConstructor}s are internally
032         * cached, repeated calls with the same specification object will yield the same result.
033         * 
034         * @param specification
035         *            the page or component specification which directs the enhancement operation
036         * @param className
037         *            the name of the base component class (in some cases,
038         *            {@link IComponentSpecification#getComponentClassName()} is null andother code
039         *            provides the default)
040         * @returns a constructor used to create instances of the enhanced component class
041         */
042    
043        ComponentConstructor getComponentConstructor(IComponentSpecification specification,
044                String className);
045    }