/*
  Copyright 2006 by Sean Luke
  Licensed under the Academic Free License version 3.0
  See the file "LICENSE" for more information
*/


package ec.util;
import java.io.Serializable;

/*
 * Parameter.java
 * Created: Sat Aug  7 12:06:49 1999
 */

/**
 *
 * 
A Parameter is an object which the ParameterDatabase class
 * uses as a key to associate with strings, forming a key-value pair.
 * Parameters are designed to be hierarchical in nature, consisting
 * of "path items" separated by a path separator.
 * Parameters are created either from a single path item, from an array
 * of path items, or both.  For example, a parameter with the path
 * foo.bar.baz might be created from 
 * new Parameter(new String[] {"foo","bar","baz"})
 * 
 * 
Parameters are not mutable -- but once a parameter is created, path 
 * items may be pushed an popped from it, forming a new parameter.
 * For example, if a parameter p consists of the path foo.bar.baz,
 * p.pop() results in a new parameter whose path is foo.bar
 * This pushing and popping isn't cheap, so be sparing.
 *
 * 
Because this system internally uses "." as its path separator, you should
 * not use that character in parts of the path that you provide; however
 * if you need some other path separator, you can change the delimiter in
 * the code trivially.
 * In fact, you can create a new Parameter with a path foo.bar.baz simply
 * by calling new Parameter("foo.bar.baz") but you'd better know
 * what you're doing.
 *
 * 
Additionally, parameters must not contain "#", "=", non-ascii values,
 * or whitespace.  Yes, a parameter path item may be empty.
 *
 * @author Sean Luke
 * @version 1.0
 */


public class Parameter implements Serializable
    {
    public String param;
    public static final char delimiter = '.';

    /** Creates a new parameter by joining the path items in s into a single path. */
    public Parameter(String[] s) throws ec.util.BadParameterException
        {
        if (s.length==0)
            throw new BadParameterException("Parameter created with length 0");
        for (int x=0;x