/interpreter/tags/at2-build270707/src/edu/vub/at/exceptions/InterpreterException.java

  1/**
  2 * AmbientTalk/2 Project
  3 * ATException.java created on Jul 13, 2006 at 8:24:20 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 edu.vub.at.eval.InvocationStack;
 31import edu.vub.at.objects.ATObject;
 32import edu.vub.at.objects.ATTypeTag;
 33import edu.vub.at.objects.natives.NATException;
 34
 35import java.io.PrintStream;
 36import java.io.PrintWriter;
 37
 38/**
 39 * TODO tvcutsem Shouldn't we parameterize NATExceptions with an ATContext and possibly
 40 * also an ATAbstractGrammar for evaluation errors. This allows the user to inspect
 41 * both which expression was evaluated at exception-raising-time and allows him to inspect
 42 * the context at exception-raising-time.
 43 * 
 44 * @author smostinc
 45 */
 46public abstract class InterpreterException extends Exception {
 47
 48	private static final long serialVersionUID = 511962997881825680L;
 49
 50	// The ambienttalk stack trace of the exception
 51	protected final InvocationStack runtimeStack_;
 52
 53	private final Throwable cause_;
 54
 55	/**
 56	 * Default constructor which only captures the AmbientTalk invocation stack.
 57	 */
 58	public InterpreterException() {
 59		super();
 60		runtimeStack_ = InvocationStack.captureInvocationStack();
 61		cause_ = null;
 62	}
 63
 64	/**
 65	 * Contructor which reports an exception with a given message and an underlying exception. 
 66	 * This constructor also captures the AmbientTalk invocation stack relating the exception
 67	 * to the AmbientTalk code that triggered it.
 68	 */
 69	public InterpreterException(String message, Throwable cause) {
 70		super(message);
 71		// Backport from JDK 1.4 to 1.3
 72		// super(message, cause);
 73		cause_ = cause;
 74		runtimeStack_ = InvocationStack.captureInvocationStack();
 75	}
 76
 77	/**
 78	 * Constructor which reports an exception with a given message which cannot be related to a
 79	 * previously raised exception. This constructor captures the AmbientTalk invocation 
 80	 * stack to identify which code produced the error.
 81	 */
 82	public InterpreterException(String message) {
 83		super(message);
 84		runtimeStack_ = InvocationStack.captureInvocationStack();
 85		cause_ = null;
 86	}
 87
 88	/**
 89	 * Constructor which creates a wrapper for an underlying exception. This constructor 
 90	 * captures the AmbientTalk invocation stack to relate the exception to the AmbientTalk
 91	 * that it corresponds to.
 92	 */
 93	public InterpreterException(Throwable cause) {
 94		// Backport from JDK 1.4 to 1.3
 95		// super(cause);
 96		cause_ = cause;
 97		runtimeStack_ = InvocationStack.captureInvocationStack();
 98	}
 99
100	
101	/**
102	 * @param out
103	 */
104	public void printAmbientTalkStackTrace(PrintStream out) {
105		runtimeStack_.printStackTrace(out);
106	}
107
108	/**
109	 * Returns an ambienttalk representation of the exception. The returned object is a wrapper
110	 * object which provides access to the exception's message and the AmbientTalk stack trace.
111	 */
112	public ATObject getAmbientTalkRepresentation() {
113		return new NATException(this);
114	}
115
116	/**
117	 * Returns the native type tag corresponding to the exception class. The NativeTypeTags class 
118	 * defines types for all native data types, including exceptions. For exceptions, these 
119	 * types can be used to catch native exceptions and handle them. Therefore every exception
120	 * class should override this abstract method to supply the type equivalent of its class.
121	 */
122	public abstract ATTypeTag getType();
123
124	public String getMessage() {
125		if (cause_ == null) {
126			return super.getMessage();
127		} else {
128			return super.getMessage() + " caused by " + cause_.getMessage();
129		}
130	}
131
132	/* backport from 1.4 interface to 1.3 */
133	/**
134	 * As AmbientTalk targets Java 1.3, Interpreter exceptions need to provide explicit support
135	 * to report the exception that caused them. The default support for such a method was only 
136	 * introduced in Java 1.4. This method returns the exception that caused a particular error
137	 * which can possibly be null.
138	 */
139	public Throwable getCause() {
140		return cause_;
141	}
142
143	public void printStackTrace(PrintStream out) {
144		if (cause_ == null) {
145			super.printStackTrace(out);
146		} else {
147			super.printStackTrace(out);
148			out.print(" caused by:");
149			cause_.printStackTrace(out);
150		}
151	}
152
153	public void printStackTrace(PrintWriter out) {
154		if (cause_ == null) {
155			super.printStackTrace(out);
156		} else {
157			super.printStackTrace(out);
158			out.print(" caused by:");
159			cause_.printStackTrace(out);
160		}
161	}
162
163	public String toString() {
164		if (cause_ == null) {
165			return super.toString();
166		} else {
167			return super.toString() + " caused by " + cause_.toString();
168		}
169	}
170}