/**
* Copyright (C) cedarsoft GmbH.
*
* Licensed under the GNU General Public License version 3 (the "License")
* with Classpath Exception; you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.cedarsoft.org/gpl3ce
* (GPL 3 with Classpath Exception)
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 3 only, as
* published by the Free Software Foundation. cedarsoft GmbH designates this
* particular file as subject to the "Classpath" exception as provided
* by cedarsoft GmbH in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 3 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 3 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact cedarsoft GmbH, 72810 Gomaringen, Germany,
* or visit www.cedarsoft.com if you need additional information or
* have any questions.
*/
package com.cedarsoft.tags;
import com.cedarsoft.NotFoundException;
import org.jetbrains.annotations.NotNull;
import java.lang.ref.WeakReference;
import java.util.Map;
import java.util.WeakHashMap;
/**
* A abstract implementation of {@link TagManager} that holds the tags in memory.
* This implementation can be used when the instance of the tag itself is not important.
*/
public abstract class MemoryTagManager<T> extends AbstractTagManager<T> {
@NotNull
protected final Map<T, WeakReference<Taggable>> store = new WeakHashMap<T, WeakReference<Taggable>>();
protected MemoryTagManager() {
super( new MemoryTagProvider() );
}
@NotNull
@Override
protected TagSet createTaggable( @NotNull T o ) {
TagSet taggable = new TagSet( o );
store.put( o, new WeakReference<Taggable>( taggable ) );
return taggable;
}
@Override
@NotNull
public Taggable findTaggable( @NotNull T o ) throws NotFoundException {
WeakReference<Taggable> weakReference = store.get( o );
if ( weakReference == null ) {
throw new NotFoundException();
}
Taggable taggable = weakReference.get();
if ( taggable == null ) {
throw new NotFoundException();
}
return taggable;
}
@NotNull
protected T getObject( @NotNull Taggable taggable ) {
for ( Map.Entry<T, WeakReference<Taggable>> entry : store.entrySet() ) {
//noinspection ObjectEquality
if ( entry.getValue().get() == taggable ) {
return entry.getKey();
}
}
throw new IllegalArgumentException( "No object found for " + taggable );
}
}