betanodebinder.java

drools 一个开放源码的规则引擎

package org.drools.reteoo;

import org.drools.FactHandle;
import org.drools.NoSuchFactObjectException;
import org.drools.WorkingMemory;
import org.drools.spi.Constraint;
import org.drools.spi.Tuple;

public class BetaNodeBinder
{
    private final Constraint  constraint;
    
    public BetaNodeBinder( )
    {
        this.constraint = null;
    }
    
    public BetaNodeBinder( Constraint constraint )
    {
        this.constraint = constraint;
    }    
    
    boolean isAllowed(Object object,
                      FactHandle handle,                      
                      Tuple tuple,
                      WorkingMemory workingMemory)
    {
        if ( constraint == null )
        {
            return true;
        }
         
        return this.constraint.isAllowed( object,
                                          handle,
                                          tuple );
        
    }
    
    boolean isAllowed(FactHandle handle,                      
                      Tuple tuple,
                      WorkingMemory workingMemory)
    {
        if ( constraint == null )
        {
            return true;
        }
        
        boolean isAllowed = false;

        try
        {
            isAllowed = isAllowed( workingMemory.getObject( handle ),
                                   handle,
                                   tuple,
                                   workingMemory );
        }
        catch ( NoSuchFactObjectException e )
        {
            //do nothing, as we return false.
            //also this should never happen
        }
        
        return isAllowed;
    }    

}