001    // Copyright 2006, 2007 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.tapestry5.ioc.internal.services;
016    
017    import org.apache.tapestry5.ioc.services.Builtin;
018    import org.apache.tapestry5.ioc.services.ClassFactory;
019    import org.apache.tapestry5.ioc.services.DefaultImplementationBuilder;
020    import org.apache.tapestry5.ioc.services.PipelineBuilder;
021    import org.slf4j.Logger;
022    
023    import java.util.List;
024    
025    public class PipelineBuilderImpl implements PipelineBuilder
026    {
027        private final ClassFactory classFactory;
028    
029        private final DefaultImplementationBuilder defaultImplementationBuilder;
030    
031        public PipelineBuilderImpl(@Builtin ClassFactory classFactory,
032    
033                                   DefaultImplementationBuilder defaultImplementationBuilder)
034        {
035            this.classFactory = classFactory;
036            this.defaultImplementationBuilder = defaultImplementationBuilder;
037        }
038    
039        public <S, F> S build(Logger logger, Class<S> serviceInterface, Class<F> filterInterface, List<F> filters)
040        {
041            S terminator = defaultImplementationBuilder.createDefaultImplementation(serviceInterface);
042    
043            return build(logger, serviceInterface, filterInterface, filters, terminator);
044        }
045    
046        public <S, F> S build(Logger logger, Class<S> serviceInterface, Class<F> filterInterface, List<F> filters,
047                              S terminator)
048        {
049            if (filters.isEmpty()) return terminator;
050    
051            BridgeBuilder<S, F> bb = new BridgeBuilder<S, F>(logger, serviceInterface, filterInterface, classFactory);
052    
053            // The first bridge will point to the terminator.
054            // Like service decorators, we work deepest (last)
055            // to shallowest (first)
056    
057            S next = terminator;
058            int count = filters.size();
059    
060            for (int i = count - 1; i >= 0; i--)
061            {
062                F filter = filters.get(i);
063    
064                next = bb.instantiateBridge(next, filter);
065            }
066    
067            return next;
068        }
069    
070    }