| /* |
| * Copyright 2008 Niclas Hedhman. All rights Reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
| * implied. |
| * |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.qi4j.library.exception; |
| |
| import java.util.Iterator; |
| import java.util.LinkedList; |
| |
| public class DelegatingExceptionObserver |
| implements ExceptionObserver |
| { |
| private LinkedList<ExceptionObserver> observers; |
| |
| public DelegatingExceptionObserver( ExceptionObserver existing ) |
| { |
| observers = new LinkedList<ExceptionObserver>(); |
| observers.add( existing ); |
| } |
| |
| public void notify( String message, Object source, Throwable exception ) |
| { |
| Iterator<ExceptionObserver> iterator; |
| synchronized( this ) |
| { |
| iterator = observers.iterator(); |
| } |
| while( iterator.hasNext() ) |
| { |
| ExceptionObserver observer = iterator.next(); |
| try |
| { |
| observer.notify( message, source, exception ); |
| } |
| catch( Throwable e ) |
| { |
| System.err.println( "WARNING: ExceptionObserver " + observer + " threw an exception. See below." ); |
| e.printStackTrace( System.err ); |
| } |
| } |
| } |
| |
| void addExceptionObserver( ExceptionObserver observer ) |
| { |
| synchronized( this ) |
| { |
| LinkedList<ExceptionObserver> clone = new LinkedList<ExceptionObserver>(); |
| clone.addAll( observers ); |
| clone.add( observer ); |
| observers = clone; |
| } |
| } |
| |
| ExceptionObserver removeExceptionObserver( ExceptionObserver observer ) |
| { |
| synchronized( this ) |
| { |
| LinkedList<ExceptionObserver> clone = new LinkedList<ExceptionObserver>(); |
| clone.addAll( observers ); |
| clone.remove( observer ); |
| if( observers.size() == 1 ) |
| { |
| ExceptionObserver last = observers.removeFirst(); |
| observers = null; |
| return last; |
| } |
| observers = clone; |
| return this; |
| } |
| } |
| |
| } |