package com.cedarsoft.utils.tags;
import com.cedarsoft.NotFoundException;
import org.jetbrains.annotations.NotNull;
import java.lang.Override;
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 );
}
}