structurewithtermsassembler.java

国外的一套开源CRM

/*
 * $Id: StructureWithTermsAssembler.java,v 1.1 2003/08/19 01:12:57 jonesde Exp $
 *
 * Copyright (c) 1999 Steven J. Metsker.
 * Copyright (c) 2001 The Open For Business Project - www.ofbiz.org
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a
 *  copy of this software and associated documentation files (the "Software"),
 *  to deal in the Software without restriction, including without limitation
 *  the rights to use, copy, modify, merge, publish, distribute, sublicense,
 *  and/or sell copies of the Software, and to permit persons to whom the
 *  Software is furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included
 *  in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 *  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 *  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 *  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT
 *  OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
 *  THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package org.ofbiz.rules.logikus;


import java.util.*;
import org.ofbiz.rules.engine.*;
import org.ofbiz.rules.parse.*;
import org.ofbiz.rules.parse.tokens.*;


/**
 * Pops the terms and functor of a structure from an assembly's stack, builds a structure, and pushes it.
 *
 * @author Steven J. Metsker
 * @version 1.0
 */
public class StructureWithTermsAssembler extends Assembler {

    /**
     * Reverse a vector into an array of terms.
     *
     * @param   v   the vector to reverse
     * @return   Term[]   the vector, reversed
     */
    public static Term[] vectorReversedIntoTerms(List v) {
        int size = v.size();
        Term[] terms = new Term[size];

        for (int i = 0; i < size; i++) {
            terms[size - 1 - i] = (Term) v.get(i);
        }
        return terms;
    }

    /**
     * Pops the terms and functor of a structure from an assembly's
     * stack, builds a structure, and pushes it.
     * <p>
     * This method expects a series of terms to lie on top of a
     * stack, with an open paren token lying underneath. If there
     * is no '(' marker, this class will throw an <code>
     * EmptyStackException</code>.
     * <p>
     * Beneath the terms of the structure, this method expects to
     * find a token whose value is the functor of the structure.
     *
     * @param  Assembly  the assembly to work on
     */
    public void workOn(Assembly a) {
        List termVector = elementsAbove(a, new Token('('));
        Term[] termArray = vectorReversedIntoTerms(termVector);
        Token t = (Token) a.pop();

        a.push(new Structure(t.value(), termArray));
    }
}