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;
016    
017    import java.util.Collection;
018    
019    import org.apache.hivemind.ClassResolver;
020    
021    /**
022     * An object that provides a component with access to helper beans. Helper beans
023     * are JavaBeans associated with a page or component that are used to extend the
024     * functionality of the component via aggregation.
025     * 
026     * @author Howard Lewis Ship
027     * @since 1.0.4
028     */
029    
030    public interface IBeanProvider
031    {
032    
033        /**
034         * Returns the JavaBean with the specified name. The bean is created as
035         * needed.
036         * 
037         * @throws ApplicationRuntimeException
038         *             if no such bean is available.
039         */
040    
041        Object getBean(String name);
042    
043        /**
044         * Returns the {@link IComponent} (which may be a
045         * {@link org.apache.tapestry.IPage}) for which this bean provider is
046         * providing beans.
047         * 
048         * @since 1.0.5
049         */
050    
051        IComponent getComponent();
052    
053        /**
054         * Returns a collection of the names of any beans which may be provided.
055         * 
056         * @since 1.0.6
057         * @see org.apache.tapestry.spec.IComponentSpecification#getBeanNames()
058         */
059    
060        Collection getBeanNames();
061    
062        /**
063         * Returns true if the provider can provide the named bean.
064         * 
065         * @since 2.2
066         */
067    
068        boolean canProvideBean(String name);
069    
070        /**
071         * Returns a resource resolver.
072         * 
073         * @since 1.0.8
074         */
075    
076        ClassResolver getClassResolver();
077    
078    }