    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 &quot;layouts&quot; 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    }