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/* ---------------------------------------------------------------------
 * Numenta Platform for Intelligent Computing (NuPIC)
 * Copyright (C) 2014, Numenta, Inc.  Unless you have an agreement
 * with Numenta, Inc., for a separate license for this software code, the
 * following terms and conditions apply:
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero Public License version 3 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero Public License for more details.
 *
 * You should have received a copy of the GNU Affero Public License
 * along with this program.  If not, see http://www.gnu.org/licenses.
 *
 * http://numenta.org/licenses/
 * ---------------------------------------------------------------------
 */

package org.numenta.nupic.model;

import java.io.Serializable;
import java.util.List;

/**
 * Base class which handles the creation of {@link Synapse}s on behalf of
 * inheriting class types.
 * 
 * @author David Ray
 * @see DistalDendrite
 * @see ProximalDendrite
 */
public abstract class Segment implements Comparable, Serializable {
    /** keep it simple */
    private static final long serialVersionUID = 1L;
    
    protected int index;
    protected Integer boxedIndex;
    
    public Segment(int index) {
        this.index = index;
        this.boxedIndex = new Integer(index);
    }
    
    /**
     * Returns this {@link ProximalDendrite}'s index.
     * @return
     */
    public int getIndex() {
        return index;
    }

    /**
     * 
     * Creates and returns a newly created {@link Synapse} with the specified
     * source cell, permanence, and index.
     * 

     * IMPORTANT: 	This method is only called for Proximal Synapses. For ProximalDendrites, 
     * 				there are many synapses within a pool, and in that case, the index 
     * 				specifies the synapse's sequence order within the pool object, and may 
     * 				be referenced by that index.
     * 
     * @param c             the connections state of the temporal memory
     * @param sourceCell    the source cell which will activate the new {@code Synapse}
     * @param pool		    the new {@link Synapse}'s pool for bound variables.
     * @param index         the new {@link Synapse}'s index.
     * @param inputIndex	the index of this {@link Synapse}'s input (source object); be it a Cell or InputVector bit.
     * 
     * @return the newly created {@code Synapse}
     * @see Connections#createSynapse(DistalDendrite, Cell, double)
     */
    public Synapse createSynapse(Connections c, List syns, Cell sourceCell, Pool pool, int index, int inputIndex) {
        Synapse s = new Synapse(c, sourceCell, this, pool, index, inputIndex);
        syns.add(s);
        return s;
    }
    
    /**
     * {@inheritDoc}
     * 
     *  Note: All comparisons use the segment's index only 
     */
    @Override
    public int compareTo(Segment arg0) {
        return boxedIndex.compareTo(arg0.boxedIndex);
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + index;
        return result;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if(this == obj)
            return true;
        if(obj == null)
            return false;
        if(getClass() != obj.getClass())
            return false;
        Segment other = (Segment)obj;
        if(index != other.index)
            return false;
        return true;
    }
    
    
}