/interpreter/tags/at2-build190607/src/edu/vub/at/exceptions/XAmbienttalk.java

 1/**
 2 * AmbientTalk/2 Project
 3 * XUserDefined.java created on Oct 10, 2006 at 9:31:40 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.exceptions;
29
30import java.io.PrintWriter;
31import java.io.StringWriter;
32
33import edu.vub.at.objects.ATObject;
34import edu.vub.at.objects.ATTypeTag;
35import edu.vub.at.objects.coercion.NativeTypeTags;
36import edu.vub.at.objects.grammar.ATSymbol;
37import edu.vub.at.objects.natives.NATText;
38import edu.vub.at.objects.natives.grammar.AGSymbol;
39
40/**
41 * The XAmbienttalk exception class is used to wrap non-primitive exceptions in the interpreter.
42 * These exceptions are objects tagged with the Exception type which should contain a message
43 * field, which this class will read out, as well as an assignable field stackTrace which this
44 * class will initialise with the correct ambienttalk stack trace.
45 *
46 * @author smostinc
47 */
48public class XAmbienttalk extends InterpreterException {
49
50	private static final ATSymbol _STACKTRACE_SYM_ = AGSymbol.jAlloc("stackTrace");
51	private static final ATSymbol _MESSAGE_SYM_ = AGSymbol.jAlloc("message");
52	
53	private static final long serialVersionUID = -2859841280138142649L;
54
55	private final ATObject customException_;
56	
57	/**
58	 * Creates a native exception wrapper given an ambienttalk exception object. This constructor
59	 * is called whenever an AmbientTalk object is being raised as this mechanism relies on the
60	 * Java level to throw an actual Java exception.
61	 * 
62	 * @param customException the object to be raised
63	 * @throws InterpreterException if the stackTrace field of the object cannot be assigned
64	 */
65	public XAmbienttalk(ATObject customException) throws InterpreterException {
66		customException_ = customException;
67		
68		StringWriter buffer = new StringWriter();
69		
70		runtimeStack_.printStackTrace(new PrintWriter(buffer, /* autoflush = */ true));
71		customException_.meta_assignField(customException_, _STACKTRACE_SYM_, NATText.atValue(buffer.toString()));
72	}
73
74	public ATObject getAmbientTalkRepresentation() {
75		return customException_;
76	}
77	
78	public ATTypeTag getType() {
79		return NativeTypeTags._CUSTOMEXCEPTION_;
80	}
81	
82	public String getMessage() {
83		try {
84			return customException_.meta_select(customException_, _MESSAGE_SYM_).asNativeText().javaValue;
85		} catch (InterpreterException e) {
86			return "A custom exception was thrown";
87		}
88	}
89}