001/* 002 * HA-JDBC: High-Availability JDBC 003 * Copyright (C) 2012 Paul Ferraro 004 * 005 * This program is free software: you can redistribute it and/or modify 006 * it under the terms of the GNU Lesser General Public License as published by 007 * the Free Software Foundation, either version 3 of the License, or 008 * (at your option) any later version. 009 * 010 * This program is distributed in the hope that it will be useful, 011 * but WITHOUT ANY WARRANTY; without even the implied warranty of 012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 013 * GNU Lesser General Public License for more details. 014 * 015 * You should have received a copy of the GNU Lesser General Public License 016 * along with this program. If not, see <http://www.gnu.org/licenses/>. 017 */ 018package net.sf.hajdbc.invocation; 019 020import java.util.SortedMap; 021import java.util.TreeMap; 022 023import net.sf.hajdbc.Database; 024import net.sf.hajdbc.DatabaseCluster; 025import net.sf.hajdbc.ExceptionFactory; 026import net.sf.hajdbc.Messages; 027import net.sf.hajdbc.balancer.Balancer; 028import net.sf.hajdbc.dialect.Dialect; 029import net.sf.hajdbc.logging.Level; 030import net.sf.hajdbc.logging.Logger; 031import net.sf.hajdbc.logging.LoggerFactory; 032import net.sf.hajdbc.sql.ProxyFactory; 033import net.sf.hajdbc.state.StateManager; 034 035/** 036 * @author paul 037 * 038 */ 039public class InvokeOnOneInvocationStrategy implements InvocationStrategy 040{ 041 private static Logger logger = LoggerFactory.getLogger(InvokeOnOneInvocationStrategy.class); 042 043 public static interface DatabaseSelector 044 { 045 <Z, D extends Database<Z>> D selectDatabase(Balancer<Z, D> balancer); 046 } 047 048 private final DatabaseSelector selector; 049 050 public InvokeOnOneInvocationStrategy(DatabaseSelector selector) 051 { 052 this.selector = selector; 053 } 054 055 /** 056 * {@inheritDoc} 057 */ 058 @Override 059 public <Z, D extends Database<Z>, T, R, E extends Exception> SortedMap<D, R> invoke(ProxyFactory<Z, D, T, E> factory, Invoker<Z, D, T, R, E> invoker) throws E 060 { 061 DatabaseCluster<Z, D> cluster = factory.getDatabaseCluster(); 062 ExceptionFactory<E> exceptionFactory = factory.getExceptionFactory(); 063 Balancer<Z, D> balancer = cluster.getBalancer(); 064 Dialect dialect = cluster.getDialect(); 065 StateManager stateManager = cluster.getStateManager(); 066 067 while (true) 068 { 069 D database = this.selector.selectDatabase(balancer); 070 071 if (database == null) 072 { 073 throw exceptionFactory.createException(Messages.NO_ACTIVE_DATABASES.getMessage(cluster)); 074 } 075 076 T object = factory.get(database); 077 078 try 079 { 080 R result = balancer.invoke(invoker, database, object); 081 082 SortedMap<D, R> resultMap = new TreeMap<D, R>(); 083 resultMap.put(database, result); 084 return resultMap; 085 } 086 catch (Exception e) 087 { 088 // If this database was concurrently deactivated, just ignore the failure 089 if (balancer.contains(database)) 090 { 091 E exception = exceptionFactory.createException(e); 092 093 if (exceptionFactory.indicatesFailure(exception, dialect)) 094 { 095 if (cluster.deactivate(database, stateManager)) 096 { 097 logger.log(Level.ERROR, exception, Messages.DATABASE_DEACTIVATED.getMessage(), database, cluster); 098 } 099 } 100 else 101 { 102 throw exception; 103 } 104 } 105 } 106 } 107 } 108}