001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.configuration.beanutils; 018 019 import java.util.Map; 020 021 /** 022 * <p> 023 * Definition of an interface for declaring a bean in a configuration file. 024 * </p> 025 * <p> 026 * Commons Configurations allows to define beans (i.e. simple Java objects) in 027 * configuration files, which can be created at runtime. This is especially 028 * useful if you program against interfaces and want to define the concrete 029 * implementation class is a configuration file. 030 * </p> 031 * <p> 032 * This interface defines methods for retrieving all information about a bean 033 * that should be created from a configuration file, e.g. the bean's properties 034 * or the factory to use for creating the instance. With different 035 * implementations different "layouts" of bean declarations can be 036 * supported. For instance if an XML configuration file is used, all features of 037 * XML (e.g. attributes, nested elements) can be used to define the bean. In a 038 * properties file the declaration format is more limited. The purpose of this 039 * interface is to abstract from the concrete declaration format. 040 * </p> 041 * 042 * @since 1.3 043 * @author Oliver Heger 044 * @version $Id: BeanDeclaration.java 439648 2006-09-02 20:42:10Z oheger $ 045 */ 046 public interface BeanDeclaration 047 { 048 /** 049 * Returns the name of the <code>BeanFactory</code> that should be used 050 * for creating the bean instance. This can be <b>null</b>, then a default 051 * factory will be used. 052 * 053 * @return the name of the bean factory 054 */ 055 String getBeanFactoryName(); 056 057 /** 058 * Here an arbitrary object can be returned that will be passed to the bean 059 * factory. Its meaning is not further specified. The purpose of this 060 * additional parameter is to support a further configuration of the bean 061 * factory that can be placed directly at the bean declaration. 062 * 063 * @return a parameter for the bean factory 064 */ 065 Object getBeanFactoryParameter(); 066 067 /** 068 * Returns the name of the bean class, from which an instance is to be 069 * created. This value must be defined unless a default class is provided 070 * for the bean creation operation. 071 * 072 * @return the name of the bean class 073 */ 074 String getBeanClassName(); 075 076 /** 077 * Returns a map with properties that should be initialized on the newly 078 * created bean. The map's keys are the names of the properties; the 079 * corresponding values are the properties' values. The return value can be 080 * <b>null</b> if no properties should be set. 081 * 082 * @return a map with properties to be initialized 083 */ 084 Map getBeanProperties(); 085 086 /** 087 * Returns a map with declarations for beans that should be set as 088 * properties of the newly created bean. This allows for complex 089 * initialization szenarios: a bean for a bean that contains complex 090 * properties (e.g. other beans) can have nested declarations for defining 091 * these complex properties. The returned map's key are the names of the 092 * properties to initialze. The values are <code>BeanDeclaration</code> 093 * implementations. They will be treated like this declaration (in a 094 * recursive manner), and the resulting beans are assigned to the 095 * corresponding properties. 096 * 097 * @return a map with nested bean declarations 098 */ 099 Map getNestedBeanDeclarations(); 100 }