/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jbpm.db.hibernate;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jbpm.JbpmException;
import org.jbpm.context.exe.Converter;
import org.jbpm.context.exe.JbpmType;
import org.jbpm.util.ClassLoaderUtil;
/**
* provides access to the list of converters and ensures that the converter objects are unique.
*/
public class Converters {
// maps class names to unique converter objects
private static final Map<String, Converter<?, ?>> convertersByClassNames = new HashMap<String, Converter<?, ?>>();
// maps converter database-id-strings to unique converter objects
private static final Map<String, Converter<?, ?>> convertersByDatabaseId = new HashMap<String, Converter<?, ?>>();
// maps unique converter objects to their database-id-string
private static final Map<Converter<?, ?>, String> convertersIds = new HashMap<Converter<?, ?>, String>();
private Converters() {
// hide default constructor to prevent instantiation
}
// public methods
public static Converter<?, ?> getConverterByClassName(String className) {
Converter<?, ?> converter = convertersByClassNames.get(className);
if (converter == null) {
Class<? extends Converter<?, ?>> converterClass = getConverterClass(className);
try {
// the converter will register itself
converter = converterClass.newInstance();
}
catch (InstantiationException e) {
log.debug("could not instantiate converter '" + className + "': " + e);
}
catch (IllegalAccessException e) {
log.debug("could not access converter: '" + className + "': " + e);
}
}
return converter;
}
public static Converter<?, ?> getConverterByDatabaseId(String databaseId) {
if (convertersByDatabaseId.isEmpty()) {
JbpmType.getJbpmTypes();
}
return convertersByDatabaseId.get(databaseId);
}
public static String getConverterId(Converter<?, ?> converter) {
// the converter has registered itself during instantiation
// hence there is no need to check whether the map is populated already
return convertersIds.get(converter);
}
public static void registerConverter(String databaseId, Converter<?, ?> converter) {
if (databaseId.length() != 1)
throw new JbpmException("converter-ids must be of length 1 (to be stored in a char)");
if (convertersByDatabaseId.containsKey(databaseId))
throw new JbpmException("duplicate converter id: '" + databaseId + "'");
log.debug("adding converter '" + databaseId + "', '" + converter + "'");
convertersByClassNames.put(converter.getClass().getName(), converter);
convertersByDatabaseId.put(databaseId, converter);
convertersIds.put(converter, databaseId);
}
@SuppressWarnings("unchecked")
private static Class<? extends Converter<?, ?>> getConverterClass(String className) {
return (Class<? extends Converter<?, ?>>) ClassLoaderUtil.classForName(className).asSubclass(
Converter.class);
}
private static Log log = LogFactory.getLog(Converters.class);
}