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Java > Open Source Codes > org > objectweb > kilim > model > ComponentSource


1 /**
2  * Copyright (C) 2002 Kelua SA
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2 of the License, or (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with this library; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  */
18
19 package org.objectweb.kilim.model;
20
21 import org.objectweb.kilim.KilimException;
22
23 /**
24  * @author horn
25  */
26     
27 public interface ComponentSource extends ComponentElement {
28     /**
29      * This method has a behaviour that depends on the exact nature of the value source.
30      * In case of properties, it simply returns the property value associated to it.
31      * In case of providers, it (re)executes the corresponding method, constructor, getter, ..... and returns the (new) obtained result.
32      * In case of unary ports two cases should be distinguished : 1) getValue() has not been previously invoked and no value is thus associated to the source.
33      * getValue() then results in the execution of the corresponding method, constructor, getter, ...... The obtained result is stored and returned after execution
34      * of the "bind" triggers.. 2) getValue() has been previously invoked. The stored result is returned.
35      * @return Object : the reference of the object provided by the source.
36      * @throws KilimException : the exception is generated when the method is invoked on unbound references or nary ports.
37      */
38     Object JavaDoc getValue() throws KilimException;
39     
40     /**
41      * returns whether a value has been evaluated and stored in the source. The behaviour of this method is
42      * highly dependant on the real nature of the source. It always returns false when invoked on a provider.
43      * @return boolean
44      * @throws KilimException : the exception is generated when the method is invoked on unbound references or nary ports.
45      */
46     boolean hasValue() throws KilimException;
47 }
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