package org.drools.reteoo;

import org.drools.FactException;
import org.drools.spi.PropagationContext;
import org.drools.spi.ReteooNode;

abstract class BaseNode
    implements
    ReteooNode
{
    protected final int id;
    
    protected boolean attachingNewNode = false;    
    
    protected boolean hasMemory = false;
    
    protected int sharedCount = 0;
        
    public BaseNode(int id)
    {
        super( );
        this.id = id;
    }

    public int getId()
    {
        return this.id;
    }
    
    public boolean isAttachingNewNode()
    {
        return this.attachingNewNode;
    }
    
    protected void setHasMemory(boolean hasMemory)
    {
        this.hasMemory = hasMemory;
    }
    
    public boolean hasMemory()
    {
        return this.hasMemory;
    }    
    
    /**
     * Attaches this node into the network.
     */
    public abstract void attach();
         
    public abstract void remove();
    
    public abstract void updateNewNode( WorkingMemoryImpl workingMemory,
                                        PropagationContext context ) throws FactException;      
    
    public void addShare()
    {
        --this.sharedCount;
    }
    
    public void removeShare()
    {
        --this.sharedCount;
        
        if ( this.sharedCount < 0 )
        {
            throw new RuntimeException( "Shared count for BaseNode should never be less than 0" );
        }
    }
    
    public boolean isShared()
    {
        return ( this.sharedCount == 0 ) ? false : true;
    }
    
    public int getSharedCount()
    {
        return this.sharedCount;
    }
    
    public int hashCode()
    {
        return this.id;
    }    
    
}