| /* |
| * 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.uid.sequence; |
| |
| import org.qi4j.api.configuration.Configuration; |
| import org.qi4j.api.injection.scope.Structure; |
| import org.qi4j.api.injection.scope.This; |
| import org.qi4j.api.property.Property; |
| import org.qi4j.api.unitofwork.ConcurrentEntityModificationException; |
| import org.qi4j.api.unitofwork.UnitOfWork; |
| import org.qi4j.api.unitofwork.UnitOfWorkCompletionException; |
| import org.qi4j.api.unitofwork.UnitOfWorkFactory; |
| |
| public class PersistedSequencingMixin |
| implements Sequencing |
| { |
| @Structure private UnitOfWorkFactory uowf; |
| @This private Configuration<Sequence> sequence; |
| |
| @Override |
| public Long newSequenceValue() |
| throws SequencingException |
| { |
| synchronized( this ) |
| { |
| ConcurrentEntityModificationException exc = null; |
| UnitOfWork uow = uowf.newUnitOfWork(); |
| try |
| { |
| for( int i = 0; i < 3; i++ ) |
| { |
| try |
| { |
| Property<Long> property = sequence.get().currentValue(); |
| long value = property.get(); |
| value = value + 1; |
| property.set( value ); |
| uow.complete(); |
| return value; |
| } |
| catch( ConcurrentEntityModificationException e ) |
| { |
| // Ignore; |
| exc = e; |
| } |
| } |
| throw new SequencingException( "Unable to update sequence value.", exc ); |
| } |
| catch( UnitOfWorkCompletionException e ) |
| { |
| throw new SequencingException( "Unable to update sequence value.", exc ); |
| } |
| } |
| } |
| |
| @Override |
| public Long currentSequenceValue() |
| { |
| synchronized( this ) |
| { |
| return sequence.get().currentValue().get(); |
| } |
| } |
| } |