001package votorola.g.lang; // Copyright 2006-2007, Michael Allan.  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Votorola Software"), to deal in the Votorola Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicence, and/or sell copies of the Votorola Software, and to permit persons to whom the Votorola Software is furnished to do so, subject to the following conditions: The preceding copyright notice and this permission notice shall be included in all copies or substantial portions of the Votorola Software. THE VOTOROLA SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE VOTOROLA SOFTWARE OR THE USE OR OTHER DEALINGS IN THE VOTOROLA SOFTWARE.
002
003import java.io.PrintStream;
004
005
006/** A catcher of errors and exceptions.
007  *
008  * <p>Subtype implementers note: if adding catch methods, bear in mind that dispatch is
009  * decided according to formal parameter type at compile time; not actual type at runtime
010  * - unlike catch statement parameters.  Best to use a new, distinct name for each new
011  * method; rather than overload the ones defined here.</p>
012  */
013public interface Catcher<S>
014{
015
016
017   // - C a t c h e r --------------------------------------------------------------------
018
019
020    /** Handles an error. Implementations would normally re-throw it as quickly as
021      * possible, taking care not to drop it first.
022      *
023      *     @param source The logical source of the error.
024      */
025    public void catchError( S source, Error r );
026
027
028
029    /** Handles an exception.
030      *
031      *     @param source The logical source of the exception.
032      */
033    public void catchException( S source, Exception x );
034
035
036
037   // ====================================================================================
038
039
040    /** Catcher utilities.
041      */
042    public @ThreadSafe static final class U
043    {
044
045        private U() {}
046
047
048        /** Prints a source indication and a stack trace, to the stream.
049          */
050        public static void printStackTrace( final Object source, final Throwable t,
051          final PrintStream stream )
052        {
053            String s;
054            try{ s = source.toString(); }
055            catch( Exception xS ) { s = "unknown"; }
056            stream.print( "CLASS " + source.getClass().getName() + "  INSTANCE " + s + "  THREW " );
057            t.printStackTrace( stream );
058        }
059
060
061    }
062
063
064}