conditionalelement.java

drools 一个开放源码的规则引擎

package org.drools.rule;

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


public abstract class ConditionalElement implements Serializable, Cloneable
{
    private List children = new ArrayList( );    
    
    public void addChild(Object child)
    {
        children.add( child );
    }
    
    public List getChildren()
    {
        return this.children;
    }          
    
    /**
     * Traverses two trees and checks that they are structurally equal at all
     * levels
     * 
     * @param e1
     * @param e2
     * @return
     */
    public boolean equals(Object object)
    {   
        // Return false if its null or not an instance of ConditionalElement
        if ( object == null || ! (object instanceof ConditionalElement))
        {
            return false;
        }
        
        // Return true if they are the same reference
        if (this == object)
        {
            return true;
        }

        //Now try a recurse manual check
        ConditionalElement e2 = (ConditionalElement) object;
        List e1Children = this.getChildren( );
        List e2Children = e2.getChildren( );
        if ( e1Children.size( ) != e2Children.size( ) )
        {
            return false;
        }

        for ( int i = 0; i < e1Children.size( ); i++ )
        {
            Object e1Object1 = e1Children.get( i );
            Object e2Object1 = e2Children.get( i );
            if ( e1Object1 instanceof ConditionalElement )
            {
                if ( e1Object1.getClass( ).isInstance( e2Object1 ) )
                {
                    if ( ! e1Object1.equals( e2Object1 ) )
                    {
                        System.out.println( e1Object1.getClass( ).getName( ) + " did not have identical children" );
                        return false;
                    }
                }
                else
                {
                    System.out.println( "Should be the equal Conditionalelements but instead was '" + e1Object1.getClass( ).getName( ) + "', '" + e2Object1.getClass( ).getName( ) + "'" );
                    return false;
                }
            }
            else if ( e1Object1 instanceof String )
            {
                if ( !e1Object1.equals( e2Object1 ) )
                {
                    System.out.println( "Should be the equal Strings but instead was '" + e1Object1 + "', '" + e2Object1 + "'" );
                    return false;
                }
            }
            else
            {
                System.out.println( "Objects are neither instances of ConditionalElement or String" );
                return false;
            }
        }

        return true;
    }
    
    public int hashCode()
    {
        return this.children.hashCode();
    }

    /**
     * Clones all Conditional Elements but references the non ConditionalElement children
     * 
     * @param e1
     * @param e2
     * @return
     */
    public Object clone()
    {
        ConditionalElement cloned = null;
        
        try
        {
            cloned = (ConditionalElement) this.getClass().newInstance();
        }
        catch ( InstantiationException e )
        {
            throw new RuntimeException("Could not clone '" + this.getClass().getName() + "'" );
        }
        catch ( IllegalAccessException e )
        {
            throw new RuntimeException("Could not clone '" + this.getClass().getName() + "'" );
        }
        
        for (Iterator it = this.children.iterator(); it.hasNext();)
        {
            Object object = it.next();
            if (object instanceof ConditionalElement)
            {
                object = ( (ConditionalElement) object).clone();
            }
            cloned.addChild( object );
                       
        }
        
        return cloned;        
    }
    
}