1 package org.apache.fulcrum.factory;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 /**
23 * The Factory Service instantiates objects using either default
24 * class loaders or a specified one. Whether specified class
25 * loaders are supported for a class depends on implementation
26 * and can be tested with the isLoaderSupported method.
27 *
28 * @author <a href="mailto:epugh@upstate.com">Eric Pugh</a>
29 * @author <a href="mailto:ilkka.priha@simsoft.fi">Ilkka Priha</a>
30 * @version $Id$
31 */
32 public interface FactoryService
33 {
34 /**
35 * The key under which this component is known by an avalon container.
36 */
37 String ROLE = FactoryService.class.getName();
38
39
40 /**
41 * Gets an instance of a class.
42 *
43 * @param <T> Type of the class
44 * @param clazz the name of the class.
45 * @return {@inheritDoc} the instance.
46 * @throws FactoryException if instantiation fails.
47 */
48 <T> T getInstance(Class<T> clazz)
49 throws FactoryException;
50
51 /**
52 * Gets an instance of a named class.
53 *
54 * @param <T> Type of the class
55 * @param className the name of the class.
56 * @return {@inheritDoc} the instance.
57 * @throws FactoryException if instantiation fails.
58 */
59 <T> T getInstance(String className)
60 throws FactoryException;
61
62 /**
63 * Gets an instance of a named class using a specified class loader.
64 *
65 * Class loaders are supported only if the isLoaderSupported
66 * method returns true. Otherwise the loader parameter is ignored.
67 *
68 * @param <T> Type of the class
69 * @param className the name of the class.
70 * @param loader the class loader.
71 * @return {@inheritDoc} the instance.
72 * @throws FactoryException if instantiation fails.
73 */
74 <T> T getInstance(String className,
75 ClassLoader loader)
76 throws FactoryException;
77
78 /**
79 * Gets an instance of a named class.
80 * Parameters for its constructor are given as an array of objects,
81 * primitive types must be wrapped with a corresponding class.
82 *
83 * @param <T> Type of the class
84 * @param className the name of the class.
85 * @param params an array containing the parameters of the constructor.
86 * @param signature an array containing the signature of the constructor.
87 * @return {@inheritDoc} the instance.
88 * @throws FactoryException if instantiation fails.
89 */
90 <T> T getInstance(String className,
91 Object[] params,
92 String[] signature)
93 throws FactoryException;
94
95 /**
96 * Gets an instance of a named class using a specified class loader.
97 * Parameters for its constructor are given as an array of objects,
98 * primitive types must be wrapped with a corresponding class.
99 *
100 * Class loaders are supported only if the isLoaderSupported
101 * method returns true. Otherwise the loader parameter is ignored.
102 *
103 * @param <T> Type of the class
104 * @param className the name of the class.
105 * @param loader the class loader.
106 * @param params an array containing the parameters of the constructor.
107 * @param signature an array containing the signature of the constructor.
108 * @return {@inheritDoc} the instance.
109 * @throws FactoryException if instantiation fails.
110 */
111 <T> T getInstance(String className,
112 ClassLoader loader,
113 Object[] params,
114 String[] signature)
115 throws FactoryException;
116
117 /**
118 * Tests if specified class loaders are supported for a named class.
119 *
120 * @param className the name of the class.
121 * @return true if class loaders are supported, false otherwise.
122 * @throws FactoryException if test fails.
123 */
124 boolean isLoaderSupported(String className)
125 throws FactoryException;
126
127 /**
128 * Gets the signature classes for parameters of a method of a class.
129 *
130 * @param clazz the class.
131 * @param params an array containing the parameters of the method.
132 * @param signature an array containing the signature of the method.
133 *
134 * @return {@inheritDoc} an array of signature classes. Note that in some cases
135 * objects in the parameter array can be switched to the context
136 * of a different class loader
137 *
138 * @throws ClassNotFoundException if any of the classes is not found.
139 */
140 Class<?>[] getSignature(Class<?> clazz,
141 Object params[],
142 String signature[])
143 throws ClassNotFoundException;
144 }