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 }