/interpreter/tags/at2dist110511/src/edu/vub/at/objects/natives/NATHandler.java

 1/**
 2 * AmbientTalk/2 Project
 3 * NATHandler.java created on Oct 14, 2006 at 8:06:53 AM
 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.natives;
29
30import edu.vub.at.exceptions.InterpreterException;
31import edu.vub.at.objects.ATBoolean;
32import edu.vub.at.objects.ATClosure;
33import edu.vub.at.objects.ATHandler;
34import edu.vub.at.objects.ATObject;
35import edu.vub.at.objects.ATTypeTag;
36import edu.vub.at.objects.ATTable;
37import edu.vub.at.objects.coercion.NativeTypeTags;
38
39/**
40 * 
41 * TODO document the class NATHandler
42 *
43 * @author smostinc
44 */
45public class NATHandler extends NATByRef implements ATHandler {
46
47	private final ATTypeTag filter_;
48	private final ATClosure handler_;
49	
50	/** construct a new exception handler */
51	public NATHandler(ATTypeTag filter, ATClosure handler) {
52		this.filter_ = filter;
53		this.handler_ = handler;
54	}
55
56	public ATBoolean base_canHandle(ATObject anException) throws InterpreterException {
57		return anException.meta_isTaggedAs(filter_);
58	}
59	
60	public ATObject base_handle(ATObject anException) throws InterpreterException {
61		return handler_.base_apply(NATTable.atValue(new ATObject[] { anException }));
62	}
63	
64	public ATHandler asHandler() {
65		return this;
66	}
67	
68    public ATTable meta_typeTags() throws InterpreterException {
69		return NATTable.of(NativeTypeTags._HANDLER_);
70	}
71    
72	public ATObject meta_clone() throws InterpreterException {
73		return this;
74	}
75
76	public NATText meta_print() throws InterpreterException {
77		return NATText.atValue("<handler for:"+filter_.toString()+">");
78	}
79}