SequenceExpressionNode.java

/*
 * This software and all files contained in it are distrubted under the MIT license.
 * 
 * Copyright (c) 2013 Cogito Learning Ltd
 * 
 * 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 uk.co.cogitolearning.cogpar;

import java.util.ArrayList;

/**
 * A base class for AdditionExpressionNode and MultiplicationExpressionNode.
 * 
 * Holds an arbitrary number of ExpressionNodes together with boolean flags.
 * 
 */
public abstract class SequenceExpressionNode implements ExpressionNode
{
  /**
   * An inner class that defines a pair containing an ExpressionNode and a
   * boolean flag.
   */
  public class Term
  {
    /** the boolean flag */
    public boolean positive;
    /** the expression node */
    public ExpressionNode expression;

    /**
     * Construct the Term object with some values.
     * @param positive the boolean flag 
     * @param expression the expression node
     */
    public Term(boolean positive, ExpressionNode expression)
    {
      super();
      this.positive = positive;
      this.expression = expression;
    }
  }

  /** the list of terms in the sequence */
  protected ArrayList<Term> terms;

  /**
   * Default constructor.
   */
  public SequenceExpressionNode()
  {
    this.terms = new ArrayList<Term>();
  }

  /**
   * Constructor to create a sequence with the first term already added.
   * 
   * @param node
   *          the term to be added
   * @param positive
   *          a boolean flag 
   */
  public SequenceExpressionNode(ExpressionNode a, boolean positive)
  {
    this.terms = new ArrayList<Term>();
    this.terms.add(new Term(positive, a));
  }

  /**
   * Add another term to the sequence
   * @param node
   *          the term to be added
   * @param positive
   *          a boolean flag 
   */
  public void add(ExpressionNode node, boolean positive)
  {
    this.terms.add(new Term(positive, node));
  }

}