Indexer.java

/*******************************************************************************
 * Copyright (c) 2004-2008 Gabor Bergmann and Daniel Varro
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Gabor Bergmann - initial API and implementation
 *******************************************************************************/

package org.eclipse.incquery.runtime.rete.index;

import java.util.Collection;

import org.eclipse.incquery.runtime.rete.network.Node;
import org.eclipse.incquery.runtime.rete.network.Supplier;
import org.eclipse.incquery.runtime.rete.tuple.Tuple;
import org.eclipse.incquery.runtime.rete.tuple.TupleMask;

/**
 * A node that indexes incoming Tuples by their signatures as specified by a TupleMask. Notifies listeners about such
 * update events through the IndexerListener.
 * 
 * Signature tuples are created by transforming the update tuples using the mask. Tuples stored with the same signature
 * are grouped together. The group or a reduction thereof is retrievable.
 * 
 * @author Gabor Bergmann
 */
public interface Indexer extends Node {
    /**
     * @return the mask by which the contents are indexed.
     */
    public TupleMask getMask();

    /**
     * @return the node whose contents are indexed.
     */
    public Supplier getParent();

    /**
     * @return all stored tuples that conform to the specified signature, null if there are none such. CONTRACT: do not
     *         modify!
     */
    public Collection<Tuple> get(Tuple signature);

    /**
     * This indexer will be updated whenever a Rete update is sent to the active node (or an equivalent time slot
     * allotted to it). The active node is typically the indexer itself, but it can be a different node such as its
     * parent.
     * 
     * @return the active node that operates this indexer
     */
    public Node getActiveNode();

    public void attachListener(IndexerListener listener);

    public void detachListener(IndexerListener listener);

}