| /* |
| * Copyright (c) OSGi Alliance (2017). All Rights Reserved. |
| * |
| * 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.osgi.util.converter; |
| |
| import java.lang.reflect.Type; |
| |
| import org.osgi.annotation.versioning.ConsumerType; |
| |
| /** |
| * An functional interface with a convert method that is passed the original |
| * object and the target type to perform a custom conversion. |
| * <P> |
| * This interface can also be used to register a custom error handler. |
| * |
| * @author $Id$ |
| */ |
| @ConsumerType |
| public interface ConverterFunction { |
| /** |
| * Special object to indicate that a custom converter rule or error handler |
| * cannot handle the conversion. |
| */ |
| static final Object CANNOT_HANDLE = new Object(); |
| |
| /** |
| * Convert the object into the target type. |
| * |
| * @param obj The object to be converted. This object will never be |
| * {@code null} as the convert function will not be invoked for |
| * null values. |
| * @param targetType The target type. |
| * @return The conversion result or {@link #CANNOT_HANDLE} to indicate that |
| * the convert function cannot handle this conversion. In this case |
| * the next matching rule or parent converter will be given a |
| * opportunity to convert. |
| * @throws Exception the operation can throw an exception if the conversion |
| * can not be performed due to incompatible types. |
| */ |
| Object apply(Object obj, Type targetType) throws Exception; |
| } |