/interpreter/tags/at_build150307/src/edu/vub/at/objects/ATHandler.java

 1/**
 2 * AmbientTalk/2 Project
 3 * ATHandler.java created on Sep 26, 2006 at 7:56:45 PM
 4 * (c) Programming Technology Lab, 2006 - 2007
 5 * Authors: Tom Van Cutsem & Stijn Mostinckx
 6 * 
 7 * Permission is hereby granted, free of charge, to any person
 8 * obtaining a copy of this software and associated documentation
 9 * files (the "Software"), to deal in the Software without
10 * restriction, including without limitation the rights to use,
11 * copy, modify, merge, publish, distribute, sublicense, and/or
12 * sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following
14 * conditions:
15 *
16 * The above copyright notice and this permission notice shall be
17 * included in all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
20 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
21 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
22 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
23 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
24 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
26 * OTHER DEALINGS IN THE SOFTWARE.
27 */
28package edu.vub.at.objects;
29
30import edu.vub.at.exceptions.InterpreterException;
31
32/**
33 * Instances of the class ATHandler represent first-class exception handlers which 
34 * have a filter object, describing the kind of exceptions caught by the handler and
35 * a code block which acts as replacement code for the code that raised the exception.
36 *
37 * @author smostinc
38 */
39public interface ATHandler extends ATObject {
40	
41	/**
42	 * Used to determine whether a handler will be triggered when an exception is raised.
43	 * Its primary use is to provide a hook to deviate from the default semantics, which is:
44	 * 
45	 * def canHandle(anException) {
46	 *   (reflect: anException).isCloneOf(filter);
47	 * };
48	 * 
49	 */
50	public ATBoolean base_canHandle(ATObject anException) throws InterpreterException;
51	
52	/**
53	 * When a handler has answered that it can handle an exception, the following
54	 * method is invoked, asking the handler to handle the exception.
55	 * The default semantics is simply to invoke the associated handler closure.
56	 * 
57	 * def handle(anException) {
58	 *   handler(anException)
59	 * };
60	 * 
61	 */
62	public ATObject base_handle(ATObject anException) throws InterpreterException;
63}