Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
BeanFactory |
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| 1.0;1 |
1 | /* | |
2 | * Licensed to the Apache Software Foundation (ASF) under one or more | |
3 | * contributor license agreements. See the NOTICE file distributed with | |
4 | * this work for additional information regarding copyright ownership. | |
5 | * The ASF licenses this file to You under the Apache License, Version 2.0 | |
6 | * (the "License"); you may not use this file except in compliance with | |
7 | * the License. You may obtain a copy of the License at | |
8 | * | |
9 | * http://www.apache.org/licenses/LICENSE-2.0 | |
10 | * | |
11 | * Unless required by applicable law or agreed to in writing, software | |
12 | * distributed under the License is distributed on an "AS IS" BASIS, | |
13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 | * See the License for the specific language governing permissions and | |
15 | * limitations under the License. | |
16 | */ | |
17 | package org.apache.commons.configuration.beanutils; | |
18 | ||
19 | /** | |
20 | * <p> | |
21 | * Definition of an interface for bean factories. | |
22 | * </p> | |
23 | * <p> | |
24 | * Beans defined in configuration files are not directly created, but by so | |
25 | * called <em>bean factories</em>. This additional level of indirection | |
26 | * provides for high flexibility in the creation process. For instance one | |
27 | * implementation of this interface could be very simple and create a new | |
28 | * instance of the specified class for each invocation. A different | |
29 | * implementation could cache already created beans and ensure that always the | |
30 | * same bean of the given class will be returned - this would be an easy mean | |
31 | * for creating singleton objects. | |
32 | * </p> | |
33 | * <p> | |
34 | * The interface itself is quite simple. There is a single method for creating a | |
35 | * bean of a given class. All necessary parameters are obtained from an also | |
36 | * passed in <code>{@link BeanDeclaration}</code> object. It is also possible | |
37 | * (but optional) for a bean factory to declare the default class of the bean it | |
38 | * creates. Then it is not necessary to specify a bean class in the bean | |
39 | * declaration. | |
40 | * </p> | |
41 | * | |
42 | * @since 1.3 | |
43 | * @author Oliver Heger | |
44 | * @version $Id: BeanFactory.java 439648 2006-09-02 20:42:10Z oheger $ | |
45 | */ | |
46 | public interface BeanFactory | |
47 | { | |
48 | /** | |
49 | * Returns a bean instance for the given class. The bean will be initialized | |
50 | * from the specified bean declaration object. It is up to a concrete | |
51 | * implementation how the bean will be created and initialized. | |
52 | * | |
53 | * @param beanClass the class for the bean | |
54 | * @param data the bean declaration object containing all data about the | |
55 | * bean to be created | |
56 | * @param param an additional parameter that may be passed by calling code; | |
57 | * it is up to a concrete implementation how this parameter is evaluated | |
58 | * @return the new bean instance (should not be <b>null</b>) | |
59 | * @throws Exception if an error occurs (the helper classes for creating | |
60 | * beans will catch this unspecific exception and wrap it in a configuration | |
61 | * exception) | |
62 | */ | |
63 | Object createBean(Class beanClass, BeanDeclaration data, Object param) | |
64 | throws Exception; | |
65 | ||
66 | /** | |
67 | * Returns the default bean class of this bean factory. If an implementation | |
68 | * here returns a non <b>null</b> value, bean declarations using this | |
69 | * factory do not need to provide the name of the bean class. In such a case | |
70 | * an instance of the default class will be created. | |
71 | * | |
72 | * @return the default class of this factory or <b>null</b> if there is | |
73 | * none | |
74 | */ | |
75 | Class getDefaultBeanClass(); | |
76 | } |