| /* |
| * 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 org.qi4j.api.injection.scope.This; |
| import org.qi4j.api.property.Property; |
| |
| public class ExceptionObservableMixin |
| implements ExceptionObservable |
| { |
| @This private Property<ExceptionObserver> observer; |
| |
| public void addExceptionObserver( ExceptionObserver observer ) |
| { |
| synchronized( this ) |
| { |
| ExceptionObserver existing = this.observer.get(); |
| if( existing == null ) |
| { |
| this.observer.set( observer ); |
| return; |
| } |
| this.observer.set( new DelegatingExceptionObserver( existing ) ); |
| } |
| } |
| |
| public void removeExceptionObserver( ExceptionObserver observer ) |
| { |
| synchronized( this ) |
| { |
| ExceptionObserver current = this.observer.get(); |
| if( current == null ) |
| { |
| return; |
| } |
| if( current == observer ) |
| { |
| this.observer.set( null ); |
| return; |
| } |
| if( current instanceof DelegatingExceptionObserver ) |
| { |
| DelegatingExceptionObserver delegator = (DelegatingExceptionObserver) this.observer; |
| this.observer.set( delegator.removeExceptionObserver( observer )); |
| } |
| } |
| } |
| |
| } |