it.tidalwave.mobile.util.LazyLookup Maven / Gradle / Ivy
/***********************************************************************************************************************
*
* blueBill Core - open source birding
* Copyright (C) 2009-2011 by Tidalwave s.a.s. (http://www.tidalwave.it)
*
***********************************************************************************************************************
*
* 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.
*
***********************************************************************************************************************
*
* WWW: http://bluebill.tidalwave.it
* SCM: https://kenai.com/hg/bluebill~core-src
*
**********************************************************************************************************************/
package it.tidalwave.mobile.util;
import javax.annotation.CheckForNull;
import javax.annotation.Nonnull;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.openide.util.Lookup;
import org.openide.util.LookupListener;
/***********************************************************************************************************************
*
* @author Fabrizio Giudici
* @version $Id$
*
**********************************************************************************************************************/
public class LazyLookup extends Lookup
{
private static final Logger log = LoggerFactory.getLogger(LazyLookup.class);
private final Map, List>> classMap = new HashMap, List>>();
private final Map, List> instanceMap = new HashMap, List>();
public void register (final @Nonnull Class interfaceClass, final @Nonnull Class implementationClass)
{
List> classes = classMap.get(interfaceClass);
if (classes == null)
{
classes = new ArrayList>();
classMap.put(interfaceClass, classes);
}
classes.add(implementationClass);
}
@Override @CheckForNull
public synchronized T lookup (final @Nonnull Class clazz)
{
log.trace("lookup({})", clazz);
final Collection instances = lookup(new Template(clazz)).allInstances();
return instances.isEmpty() ? null : instances.iterator().next();
}
@Override @CheckForNull
public Result lookup (final @Nonnull Template template)
{
log.trace("lookup({})", template);
final Class type = template.getType();
return new Result()
{
@Override
public void addLookupListener(LookupListener l)
{
}
@Override
public void removeLookupListener(LookupListener l)
{
}
@Override @Nonnull
public Collection allInstances()
{
List instances = (List)instanceMap.get(type);
if (instances == null)
{
instances = new ArrayList();
instanceMap.put(type, instances);
final List temp = classMap.get(type); // FIXME: workaround for cast
List> implementationClasses = (List>)temp;
if (implementationClasses != null)
{
for (Class implementationClass : implementationClasses)
{
try
{
final T instance = implementationClass.newInstance();
instances.add(instance);
}
catch (InstantiationException e)
{
throw new RuntimeException(e);
}
catch (IllegalAccessException e)
{
throw new RuntimeException(e);
}
}
}
}
// logger.finest(">>>> returning %s", results);
return Collections.unmodifiableList(instances);
}
};
}
}