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Java > Open Source Codes > bsh > EvalError


1 /*****************************************************************************
2  * *
3  * This file is part of the BeanShell Java Scripting distribution. *
4  * Documentation and updates may be found at http://www.beanshell.org/ *
5  * *
6  * Sun Public License Notice: *
7  * *
8  * The contents of this file are subject to the Sun Public License Version *
9  * 1.0 (the "License"); you may not use this file except in compliance with *
10  * the License. A copy of the License is available at http://www.sun.com *
11  * *
12  * The Original Code is BeanShell. The Initial Developer of the Original *
13  * Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright *
14  * (C) 2000. All Rights Reserved. *
15  * *
16  * GNU Public License Notice: *
17  * *
18  * Alternatively, the contents of this file may be used under the terms of *
19  * the GNU Lesser General Public License (the "LGPL"), in which case the *
20  * provisions of LGPL are applicable instead of those above. If you wish to *
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22  * and not to allow others to use your version of this file under the SPL, *
23  * indicate your decision by deleting the provisions above and replace *
24  * them with the notice and other provisions required by the LGPL. If you *
25  * do not delete the provisions above, a recipient may use your version of *
26  * this file under either the SPL or the LGPL. *
27  * *
28  * Patrick Niemeyer (pat@pat.net) *
29  * Author of Learning Java, O'Reilly & Associates *
30  * http://www.pat.net/~pat/ *
31  * *
32  *****************************************************************************/
33
34
35 package bsh;
36
37 /**
38     EvalError indicates that we cannot continue evaluating the script
39     or the script has thrown an exception.
40
41     EvalError may be thrown for a script syntax error, an evaluation
42     error such as referring to an undefined variable, an internal error.
43     <p>
44     
45     @see TargetError
46 */
47 public class EvalError extends Exception JavaDoc
48 {
49     SimpleNode node;
50
51     // Note: no way to mutate the Throwable message, must maintain our own
52 String JavaDoc message;
53
54     CallStack callstack;
55
56     public EvalError( String JavaDoc s, SimpleNode node, CallStack callstack ) {
57         setMessage(s);
58         this.node = node;
59         // freeze the callstack for the stack trace.
60 if ( callstack != null )
61             this.callstack = callstack.copy();
62     }
63
64     /**
65         Print the error with line number and stack trace.
66     */
67     public String JavaDoc toString()
68     {
69         String JavaDoc trace;
70         if ( node != null )
71             trace = " : at Line: "+ node.getLineNumber()
72                 + " : in file: "+ node.getSourceFile()
73                 + " : "+node.getText();
74         else
75             // Users should not normally see this.
76 trace = ": <at unknown location>";
77
78         if ( callstack != null )
79             trace = trace +"\n" + getScriptStackTrace();
80
81         return getMessage() + trace;
82     }
83
84     /**
85         Re-throw the error, prepending the specified message.
86     */
87     public void reThrow( String JavaDoc msg )
88         throws EvalError
89     {
90         prependMessage( msg );
91         throw this;
92     }
93
94     /**
95         The error has trace info associated with it.
96         i.e. It has an AST node that can print its location and source text.
97     */
98     SimpleNode getNode() {
99         return node;
100     }
101
102     void setNode( SimpleNode node ) {
103         this.node = node;
104     }
105
106     public String JavaDoc getErrorText() {
107         if ( node != null )
108             return node.getText() ;
109         else
110             return "<unknown error>";
111     }
112
113     public int getErrorLineNumber() {
114         if ( node != null )
115             return node.getLineNumber() ;
116         else
117             return -1;
118     }
119
120     public String JavaDoc getErrorSourceFile() {
121         if ( node != null )
122             return node.getSourceFile() ;
123         else
124             return "<unknown file>";
125     }
126
127     public String JavaDoc getScriptStackTrace()
128     {
129         if ( callstack == null )
130             return "<Unknown>";
131
132         String JavaDoc trace = "";
133         CallStack stack = callstack.copy();
134         while ( stack.depth() > 0 )
135         {
136             NameSpace ns = stack.pop();
137             SimpleNode node = ns.getNode();
138             if ( ns.isMethod )
139             {
140                 trace = trace + "\nCalled from method: " + ns.getName();
141                 if ( node != null )
142                     trace += " : at Line: "+ node.getLineNumber()
143                         + " : in file: "+ node.getSourceFile()
144                         + " : "+node.getText();
145             }
146         }
147
148         return trace;
149     }
150
151     /**
152         @see #toString() for a full display of the information
153     */
154     public String JavaDoc getMessage() { return message; }
155
156     public void setMessage( String JavaDoc s ) { message = s; }
157
158     /**
159         Prepend the message if it is non-null.
160     */
161     protected void prependMessage( String JavaDoc s )
162     {
163         if ( s == null )
164             return;
165
166         if ( message == null )
167             message = s;
168         else
169             message = s + " : "+ message;
170     }
171
172 }
173
174
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