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Jadex Rules is a small lightweight rule engine, which currently employs the well-known Rete algorithm for highly efficient rule matching. Jadex rules is therefore similar to other rule engines like JESS and Drools. Despite the similarities there are also important differences between these systems: * Jadex Rules is very small and intended to be used as component of other software. Even though rules can be specified in a Java dialect as well as (a small variation of) the CLIPS language its primary usage is on the API level. Jadex Rules is currently the core component of the Jadex BDI reasoning engine. * Jadex Rules cleanly separates between state and rule representation. This allows the state implementation as well as the matcher to be flexibly exchanged. Some experiments have e.g. been conducted with a Jena representation. Regarding the matcher, it is planned to support also the Treat algorithm, which has a lower memory footprint than Rete. * Jadex Rules pays close attention to rule debugging. The state as well as the rete engine can be observed at runtime. The rule debugger provides functionalities to execute a rule program stepwise and also use rule breakpoints to stop the execution at those points.

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package jadex.rules.rulesystem.rete.nodes;

import jadex.rules.rulesystem.rete.Tuple;
import jadex.rules.state.IOAVState;
import jadex.rules.state.OAVJavaType;
import jadex.rules.state.OAVObjectType;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 *  A mixed identity hash map allows to store java objects
 *  using identity and java values (numbers, strings, etc.)
 *  using equality. Rete tuples are always stored by equality. 
 */
public class MixedIdentityHashMap	implements Map
{
	//-------- attributes --------
	
	/** The state. */
	protected IOAVState	state;
	
	/** The equality map. */
	protected Map	equality;
	
	/** The identity map. */
	protected Map	identity;
	
	//-------- constructors --------
	
	/**
	 *  Create a new mixed identity map.
	 */
	public MixedIdentityHashMap(IOAVState state)
	{
		this.state	= state;
		this.equality	= new LinkedHashMap();
		this.identity	= new IdentityHashMap();
	}
	
	//-------- Map interface --------

	public void clear()
	{
		equality.clear();
		identity.clear();
	}
	
	public boolean containsKey(Object key)
	{
		return equality.containsKey(key) || identity.containsKey(key);
	}

	public boolean containsValue(Object value)
	{
		return equality.containsValue(value) || identity.containsValue(value);
	}
	
	public Object get(Object key)
	{
		return equality.containsKey(key) ? equality.get(key) : identity.get(key); 
	}
	
	public boolean isEmpty()
	{
		return equality.isEmpty() && identity.isEmpty();
	}
	
	public Object put(Object key, Object value)
	{
		OAVObjectType	type	= key!=null && !(key instanceof Tuple) ? state.getType(key) : null;
		return type instanceof OAVJavaType && !OAVJavaType.KIND_VALUE.equals(((OAVJavaType)type).getKind())
			? identity.put(key, value) : equality.put(key, value);
	}
	
	public void putAll(Map map)
	{
		for(Iterator it=map.keySet().iterator(); it.hasNext();)
		{
			Object	key	= it.next();
			put(key, map.get(key));
		}
	}
	
	public Object remove(Object key)
	{
		return equality.containsKey(key) ? equality.remove(key) : identity.remove(key); 
	}
	
	public int size()
	{
		return equality.size() + identity.size();
	}
	
	public Collection values()
	{
		List vals = new ArrayList();
		vals.addAll(equality.values());
		vals.addAll(identity.values());
		return vals;
	}

	public Set entrySet()
	{
		throw new UnsupportedOperationException("Not yet implemented");
	}
	
	public Set keySet()
	{
		Set keys = new HashSet();
		keys.addAll(equality.keySet());
		keys.addAll(identity.keySet());
		return keys;
	}

	public int hashCode()
	{
		final int prime = 31;
		int result = 1;
		result = prime * result
			+ ((equality == null) ? 0 : equality.hashCode());
		result = prime * result
			+ ((identity == null) ? 0 : identity.hashCode());
		result = prime * result + ((state == null) ? 0 : state.hashCode());
		return result;
	}

	public boolean equals(Object obj)
	{
		boolean ret = false;
		if(obj instanceof MixedIdentityHashMap)
		{
			MixedIdentityHashMap other = (MixedIdentityHashMap)obj;
			ret = equality.equals(other.equality) && identity.equals(other.identity) && state.equals(other.state);
		}
		return ret;
	}
	
		
}