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Fabric3 SPIs for component introspection.
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/*
 * Fabric3
 * Copyright ? 2008 Metaform Systems Limited
 *
 * This proprietary software may be used only connection with the Fabric3 license
 * (the ?License?), a copy of which is included in the software or may be
 * obtained at: http://www.metaformsystems.com/licenses/license.html.

 * Software distributed under the License is distributed on an ?as is? basis,
 * without warranties or conditions of any kind.  See the License for the
 * specific language governing permissions and limitations of use of the software.
 * This software is distributed in conjunction with other software licensed under
 * different terms.  See the separate licenses for those programs included in the
 * distribution for the permitted and restricted uses of such software.
 *
 * --- Original Apache License ---
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.fabric3.introspection;

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Set;

import org.fabric3.introspection.java.ImplementationNotFoundException;
import org.fabric3.scdl.InjectableAttributeType;
import org.fabric3.scdl.ServiceDefinition;

/**
 * Helper service that provides support methods to simplify introspection.
 *
 * @version $Rev: 5481 $ $Date: 2008-09-26 02:36:30 -0700 (Fri, 26 Sep 2008) $
 */
public interface IntrospectionHelper {

    /**
     * Load the class using the supplied ClassLoader. The class will be defined so any initializers present will be
     * fired. As the class is being loaded, the Thread context ClassLoader will be set to the supplied classloader.
     *
     * @param name the name of the class to load
     * @param cl   the classloader to use to load it
     * @return the class
     * @throws org.fabric3.introspection.java.ImplementationNotFoundException if the class could not be found
     */
    Class loadClass(String name, ClassLoader cl) throws ImplementationNotFoundException;

    /**
     * Derive the name of an injection site from a field.
     *
     * @param field    the field to inspect
     * @param override an override specified in an annotation
     * @return the name of the injection site
     */
    String getSiteName(Field field, String override);

    /**
     * Derive the name of an injection site from a setter method.
     *
     * @param setter   the setter method to inspect
     * @param override an override specified in an annotation
     * @return the name of the injection site
     */
    String getSiteName(Method setter, String override);

    /**
     * Derive the name of an injection site from a setter method.
     *
     * @param constructor the constructor to inspect
     * @param index       the index of the constructor parameter to inspect
     * @param override    an override specified in an annotation
     * @return the name of the injection site
     */
    String getSiteName(Constructor constructor, int index, String override);

    /**
     * Returns the generic type of a setter method.
     *
     * @param setter the method to inspect
     * @return the type of value the setter method injects
     */
    Type getGenericType(Method setter);

    /**
     * Returns the generic type of a method parameter.
     *
     * @param method the method to inspect
     * @param index  the parameter index
     * @return the type of value the method injects
     */
    Type getGenericType(Method method, int index);

    /**
     * Returns the generic type of a constructor parameter.
     *
     * @param constructor the constructor to inspect
     * @param index       the parameter index
     * @return the type of value the constructor injects
     */
    Type getGenericType(Constructor constructor, int index);

    /**
     * Returns true if the supplied type should be treated as many-valued.
     * 
     * This is generally true for arrays, Collection or Map types.
     *
     * @param typeMapping the mapping to use to resolve any formal types
     * @param type        the type to check
     * @return true if the type should be treated as many-valued
     */
    boolean isManyValued(TypeMapping typeMapping, Type type);

    InjectableAttributeType inferType(Type type, TypeMapping typeMapping);

    /**
     * Determine if an annotation is present on this interface or any superinterface.
     * 

     * This is similar to the use of @Inherited on classes (given @Inherited does not apply to interfaces).
     *
     * @param type           the interface to check
     * @param annotationType the annotation to look for
     * @return true if the annotation is present
     */
    boolean isAnnotationPresent(Class type, Class annotationType);

    /**
     * Map the formal parameters of a type, its superclass and superinterfaces to the actual parameters of the class.
     *
     * @param type the class whose parameters should be mapped
     * @return a mapping of formal type parameters to actual types
     */
    TypeMapping mapTypeParameters(Class type);

    /**
     * Returns the base type for the supplied type.
     * 

     * The base type is the actual type of a property or reference having removed any decoration for arrays or collections.
     *
     * @param type        the type of a field or parameter
     * @param typeMapping the mapping to use to resolve any formal types
     * @return the actual type of the property or reference corresponding to the parameter
     */
    Type getBaseType(Type type, TypeMapping typeMapping);

    /**
     * Returns all service interfaces directly implemented by a class or any superclass.
     * 

     * Class#getInterfaces only returns interfaces directly implemented by the class. This method returns all interfaces including those implemented
     * by any superclasses. It excludes interfaces that are super-interfaces of those implemented by subclasses.
     *
     * @param type the class whose interfaces should be returned
     * @return the unique interfaces immplemented by that class
     */
    Set> getImplementedInterfaces(Class type);

    /**
     * Returns method injection sites provided by a class or any superclass.
     * 

     * Methods that are part of any service contract are excluded.
     *
     * @param type     the class whose method sites should be returned
     * @param services the services implemented by the class
     * @return the method injection sites for the class
     */
    Set getInjectionMethods(Class type, Collection services);

    /**
     * Returns method injection sites provided by a class or any superclass.
     * 
     * Methods that are part of any service contract are excluded.
     *
     * @param type the class whose field injection sites should be returned
     * @return the setter injection sites for the class
     */
    Set getInjectionFields(Class type);
}