/*******************************************************************************
* Copyright 2014 Analog Devices, Inc.
*
* 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.
********************************************************************************/
package com.analog.lyric.dimple.model.core;
import net.jcip.annotations.GuardedBy;
import net.jcip.annotations.ThreadSafe;
import org.eclipse.jdt.annotation.Nullable;
import com.analog.lyric.collect.WeakIntHashMap;
import com.analog.lyric.dimple.environment.DimpleEnvironment;
import com.analog.lyric.util.misc.Internal;
/**
* Registry of known {@link FactorGraph}s associated with a {@link DimpleEnvironment}.
* <p>
* Obtain instance from {@linkplain DimpleEnvironment#factorGraphs factorGraphs()} accessor
* on {@link DimpleEnvironment} instance.
* <p>
* @since 0.08
* @author Christopher Barber
*/
@ThreadSafe
public class FactorGraphRegistry
{
/*-------
* State
*/
private static final int MAX_GRAPH_ID = (1<<28) - 1;
@GuardedBy("this")
private long _nextId = 0;
@GuardedBy("this")
private final WeakIntHashMap<FactorGraph> _graphById = new WeakIntHashMap<>();
/*--------------
* Construction
*/
@Internal
public FactorGraphRegistry()
{
}
/*---------
* Methods
*/
/**
* Returns factor graph with given graph id
* @param graphId is the {@linkplain FactorGraph#getGraphId graph id} of the graph to return.
* @return the graph with given id or null if it doesn't exist.
* @since 0.08
*/
public @Nullable FactorGraph getGraphWithId(int graphId)
{
synchronized(this)
{
return _graphById.get(graphId);
}
}
int registerIdForFactorGraph(FactorGraph fg)
{
synchronized(_graphById)
{
long longid = ++_nextId;
int id = (int)longid & MAX_GRAPH_ID;
if (longid > MAX_GRAPH_ID)
{
// Id wrapped around. Need to find next available slot.
while (id != 0 && _graphById.containsKey(id))
{
id = (int)++_nextId & MAX_GRAPH_ID;
}
}
_graphById.put(id, fg);
return id;
}
}
}