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Core interpreter artifact for the ASTRA Language

There is a newer version: 1.4.2

package astra.core;

import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Queue;

import astra.formula.Formula;
import astra.formula.Predicate;
import astra.reasoner.Queryable;

/**
 * Container for storing beliefs.
 * 
 * Beliefs are organised into lists of formulae that have the same predicate through the use of
 * a Map.
 *  
 * @author Rem
 *
 */
public class BeliefStore {
	private Map> store = new HashMap>();
	int size = 0;
	
	public boolean addBelief(Predicate belief) {
		List list = store.get(belief.id());
		if (list == null) {
			list = new LinkedList();
			store.put(belief.id(), list);
		}
		
		for (Formula element : list) {
			if (element.equals(belief)) return false;
		}
		
		list.add(belief);
		size++;
		return true;
	}
	
	public boolean containsBelief(Predicate belief) {
		List list = store.get(belief.id());
		if (list == null) return false;
		
		for (Formula element : list) {
			if (element.equals(belief)) return true;
		}
		
		return false;
	}

	public boolean removeBelief(Predicate belief) {
		List list = store.get(belief.id());
		if (list == null) return false;
		
		for (Formula element : list) {
			if (element.equals(belief)) {
				list.remove(element);
				size--;
				return true;
			}
		}
		
		return false;
	}

	public List beliefs() {
		List list = new LinkedList();
		for (List l : store.values()) {
			list.addAll(l);
		}
		return list;
	}

	public void clear() {
		store.clear();
	}

	public void addMatchingBeliefs(Queue queue, Predicate formula) {
		List list = store.get(formula.id());
		if (list != null) queue.addAll(list);
	}

	public Iterator iterator(Formula formula) {
		if (formula instanceof Predicate) {
			List list = store.get(((Predicate) formula).id());
			return list == null ? Queryable.EMPTY_LIST.iterator():list.iterator();
		}
		return Queryable.EMPTY_LIST.iterator();
	}

	public int size() {
		return size;
	}
}