    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.MethodSignature;
    018
    019    /**
    020     * Used by {@link org.apache.tapestry5.ioc.internal.services.PipelineBuilderImpl} to analyze service interface methods
    021     * against filter interface methods to find the position of the extra service parameter (in the filter method).
    022     */
    023    public class FilterMethodAnalyzer
    024    {
    025        private final Class serviceInterface;
    026
    027        FilterMethodAnalyzer(Class serviceInterface)
    028        {
    029            this.serviceInterface = serviceInterface;
    030        }
    031
    032        public int findServiceInterfacePosition(MethodSignature ms, MethodSignature fms)
    033        {
    034            if (ms.getReturnType() != fms.getReturnType()) return -1;
    035
    036            if (!ms.getName().equals(fms.getName())) return -1;
    037
    038            Class[] filterParameters = fms.getParameterTypes();
    039            int filterParameterCount = filterParameters.length;
    040            Class[] serviceParameters = ms.getParameterTypes();
    041
    042            if (filterParameterCount != (serviceParameters.length + 1)) return -1;
    043
    044            // TODO: check compatible exceptions!
    045
    046            // This needs work; it assumes the first occurance of the service interface
    047            // in the filter interface method signature is the right match. That will suit
    048            // most of the time.
    049
    050            boolean found = false;
    051            int result = -1;
    052
    053            for (int i = 0; i < filterParameterCount; i++)
    054            {
    055                if (filterParameters[i] == serviceInterface)
    056                {
    057                    result = i;
    058                    found = true;
    059                    break;
    060                }
    061            }
    062
    063            if (!found) return -1;
    064
    065            // Check that all the parameters before and after the service interface still
    066            // match.
    067
    068            for (int i = 0; i < result; i++)
    069            {
    070                if (filterParameters[i] != serviceParameters[i]) return -1;
    071            }
    072
    073            for (int i = result + 1; i < filterParameterCount; i++)
    074            {
    075                if (filterParameters[i] != serviceParameters[i - 1]) return -1;
    076            }
    077
    078            return result;
    079        }
    080
    081    }