Class ParsedFunction

src/org/opensourcephysics/numerics/ParsedFunction.java:20–70

ParsedFunction defines a function of a single varianble using a String. This function is immutable. That is, once an instance is created with a particular function string, the function cannot be changed. Because immutable objects cannot change, they are thread safe and can be freely shared in a J

 * @author Wolfgang Christian
 */
public final class ParsedFunction implements Function {
  private final String fStr;
  private final Function function;

  /**
   * Constructs a function x with from the given string.
   *
   * @param fStr the function
   * @throws ParserException
   */
  public ParsedFunction(String fStr) throws ParserException {
    this(fStr, "x"); //$NON-NLS-1$
  }

  /**
   * Constructs a ParsedFunction from the given string and independent variable.
   *
   * @param _fStr the function
   * @param var the independent variable
   * @throws ParserException
   */
  public ParsedFunction(String _fStr, String var) throws ParserException {
    fStr = _fStr;
    SuryonoParser parser = null;
    parser = new SuryonoParser(fStr, var);
    function = parser;
  }

  /**
   * Evaluates the function, f.
   *
   * @param x the value of the independent variable
   *
   * @return the value of the function
   */
  @Override
public double evaluate(double x) {
    return function.evaluate(x);
  }

  /**
   * Represents the function as a string.
   *
   * @return the string
   */
  @Override
public String toString() {
    return "f(x) = "+fStr; //$NON-NLS-1$
  }

}

/*
 * Open Source Physics software is free software; you can redistribute