FunctionExpressionNode.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;

public class FunctionExpressionNode implements ExpressionNode
{
  public static final int SIN = 1;
  public static final int COS = 2;
  public static final int TAN = 3;

  public static final int ASIN = 4;
  public static final int ACOS = 5;
  public static final int ATAN = 6;

  public static final int SQRT = 7;
  public static final int EXP = 8;

  public static final int LN = 9;
  public static final int LOG = 10;
  public static final int LOG2 = 11;

  private int function;

  private ExpressionNode argument;

  public FunctionExpressionNode(int function, ExpressionNode argument)
  {
    super();
    this.function = function;
    this.argument = argument;
  }

  public int getType()
  {
    return ExpressionNode.FUNCTION_NODE;
  }

  public static int stringToFunction(String str)
  {
    if (str.equals("sin"))
      return FunctionExpressionNode.SIN;
    if (str.equals("cos"))
      return FunctionExpressionNode.COS;
    if (str.equals("tan"))
      return FunctionExpressionNode.TAN;

    if (str.equals("asin"))
      return FunctionExpressionNode.ASIN;
    if (str.equals("acos"))
      return FunctionExpressionNode.ACOS;
    if (str.equals("atan"))
      return FunctionExpressionNode.ATAN;

    if (str.equals("sqrt"))
      return FunctionExpressionNode.SQRT;
    if (str.equals("exp"))
      return FunctionExpressionNode.EXP;

    if (str.equals("ln"))
      return FunctionExpressionNode.LN;
    if (str.equals("log"))
      return FunctionExpressionNode.LOG;
    if (str.equals("log2"))
      return FunctionExpressionNode.LOG2;

    throw new ParserException("Unexpected Function " + str + " found");
  }

  public static String getAllFunctions()
  {
    return "sin|cos|tan|asin|acos|atan|sqrt|exp|ln|log|log2";
  }

  public double getValue()
  {
    switch (function)
    {
      case SIN:
        return Math.sin(argument.getValue());
      case COS:
        return Math.cos(argument.getValue());
      case TAN:
        return Math.tan(argument.getValue());
      case ASIN:
        return Math.asin(argument.getValue());
      case ACOS:
        return Math.acos(argument.getValue());
      case ATAN:
        return Math.atan(argument.getValue());
      case SQRT:
        return Math.sqrt(argument.getValue());
      case EXP:
        return Math.exp(argument.getValue());
      case LN:
        return Math.log(argument.getValue());
      case LOG:
        return Math.log(argument.getValue()) * 0.43429448190325182765;
      case LOG2:
        return Math.log(argument.getValue()) * 1.442695040888963407360;
    }

    throw new EvaluationException("Invalid function id "+function+"!");
  }

  public void accept(ExpressionNodeVisitor visitor)
  {
    visitor.visit(this);
    argument.accept(visitor);
  }

}