001    // Copyright 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.annotations;
016    
017    import java.beans.Introspector;
018    import java.lang.reflect.Method;
019    
020    import org.apache.hivemind.ApplicationRuntimeException;
021    
022    /**
023     * @author Howard M. Lewis Ship
024     * @since 4.0
025     */
026    
027    public class AnnotationUtils
028    {
029        public static String getPropertyName(Method method)
030        {
031            String name = method.getName();
032    
033            if (name.startsWith("is"))
034            {
035                checkGetter(method);
036                return Introspector.decapitalize(name.substring(2));
037            }
038    
039            if (name.startsWith("get"))
040            {
041                checkGetter(method);
042                return Introspector.decapitalize(name.substring(3));
043            }
044    
045            if (name.startsWith("set"))
046            {
047                checkSetter(method);
048                return Introspector.decapitalize(name.substring(3));
049            }
050    
051            throw new ApplicationRuntimeException(AnnotationMessages.notAccessor(method));
052        }
053    
054        private static void checkGetter(Method method)
055        {
056            if (method.getParameterTypes().length > 0)
057                throw new ApplicationRuntimeException(AnnotationMessages.noParametersExpected(method));
058    
059            if (method.getReturnType().equals(void.class))
060                throw new ApplicationRuntimeException(AnnotationMessages.voidAccessor(method));
061    
062        }
063    
064        private static void checkSetter(Method method)
065        {
066            if (!method.getReturnType().equals(void.class))
067                throw new ApplicationRuntimeException(AnnotationMessages.nonVoidMutator(method));
068    
069            if (method.getParameterTypes().length != 1)
070                throw new ApplicationRuntimeException(AnnotationMessages.wrongParameterCount(method));
071        }
072    }