core/api/src/main/java/org/qi4j/api/property/GenericPropertyInfo.java

/*
 * Copyright 2007,2008 Niclas Hedhman.
 *
 * Licensed  under the  Apache License,  Version 2.0  (the "License");
 * you may not use  this file  except in  compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed  under the  License is distributed on an "AS IS" BASIS,
 * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY KIND, either  express  or
 * implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.qi4j.api.property;

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import static org.qi4j.api.util.Classes.typeOf;

/**
 * Generic Property info utility class.
 */
public final class GenericPropertyInfo
{
    public static Type propertyTypeOf( AccessibleObject accessor )
    {
        return toPropertyType( typeOf( accessor ) );
    }

    public static Type toPropertyType( Type methodReturnType )
    {
        if( methodReturnType instanceof ParameterizedType )
        {
            ParameterizedType parameterizedType = (ParameterizedType) methodReturnType;
            if( Property.class.isAssignableFrom( (Class<?>) parameterizedType.getRawType() ) )
            {
                return parameterizedType.getActualTypeArguments()[ 0 ];
            }
        }

        if( methodReturnType instanceof Class<?> )
        {
            Type[] interfaces = ( (Class<?>) methodReturnType ).getGenericInterfaces();
            for( Type anInterface : interfaces )
            {
                Type propertyType = toPropertyType( anInterface );
                if( propertyType != null )
                {
                    return propertyType;
                }
            }
        }
        return null;
    }
}