Relation.java

/**
 *  Copyright (C) 2002-2012   The FreeCol Team
 *
 *  This file is part of FreeCol.
 *
 *  FreeCol is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  FreeCol is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.client.gui.i18n;

import java.util.List;

public class Relation {

    int low, high, mod = 1;
    boolean negated = false;
    boolean integer = true;

    public Relation(List<String> tokens) {
	parse(tokens);
    }

    public Relation(int low, int high) {
	this.low = low;
	this.high = high;
    }

    /**
     * Sets the divisor for a modulo operation (defaults to 1).
     *
     * @param mod an <code>int</code> value
     */
    public void setMod(int mod) {
	this.mod = mod;
    }

    /**
     * Negates the return value of the relation (defaults to false).
     *
     * @param value a <code>boolean</code> value
     */
    public void setNegated(boolean value) {
	this.negated = value;
    }

    /**
     * Determines whether this relation only matches integers
     * (defaults to true).
     *
     * @param value a <code>boolean</code> value
     */
    public void setInteger(boolean value) {
	this.integer = value;
    }

    /**
     * Returns true if the given number matches this relation.
     *
     * @param number a <code>double</code> value
     * @return a <code>boolean</code> value
     */
    public boolean matches(double number) {
	double value = (mod == 1) ? number : number % mod;
	if (integer && value != (int) value) {
	    return false;
	}
	return (low <= value && value <= high) != negated;
    }

    @Override
    public String toString() {
	String result = new String("n ");
	if (mod != 1) {
	    result += "mod " + Integer.toString(mod) + " ";
	}
	if (low == high) {
	    result += "is ";
	    if (negated) {
		result += "not ";
	    }
	    result += Integer.toString(low);
	} else {
	    if (negated) {
		result += "not ";
	    }
	    if (!integer) {
		result += "with";
	    }
	    result += "in " + Integer.toString(low)
		+ ".." + Integer.toString(high);
	}
	return result;
    }


    /**
     * Parses a list of string tokens.
     *
     * @param input a list of string tokens
     */
    private void parse(List<String> input) {
	String token = input.remove(0);
	if ("n".equals(token)) {
	    token = input.remove(0);
	} else {
	    throw new IllegalArgumentException("Relation must start with 'n'.");
	}
	if ("mod".equals(token)) {
	    mod = Integer.parseInt(input.remove(0));
	    token = input.remove(0);
	}
	if ("not".equals(token)) {
	    negated = true;
	    token = input.remove(0);
	}
	if ("is".equals(token)) {
	    token = input.remove(0);
	    if ("not".equals(token)) {
		negated = true;
		token = input.remove(0);
	    }
	    low = high = Integer.parseInt(token);
	} else {
	    if ("within".equals(token)) {
		integer = false;
	    }
	    low = Integer.parseInt(input.remove(0));
	    high = Integer.parseInt(input.remove(0));
	}
    }

}