Utilities.java

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/*
    Synthia, a data structure generator
    Copyright (C) 2019-2021 Laboratoire d'informatique formelle
    Université du Québec à Chicoutimi, Canada
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program 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 Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package examples.util;
 
import java.io.PrintStream;
import java.lang.reflect.Array;
import java.util.Collection;
 
/**
 * Object providing a few utility methods to simplify the examples in this
 * project.
 * @ingroup Examples
 */
public class Utilities
{
    /**
     * Prints an object to a print stream.
     * @param ps The print stream to print to
     * @param o The object
     */
    public static void print(PrintStream ps, Object o)
    {
        if (o == null)
        {
            ps.print("null");
        }
        else if (o.getClass().isArray())
        {
            ps.print("[");
            if (o.getClass().getComponentType().isPrimitive()) 
            {
                int length = Array.getLength(o);
                for (int i = 0; i < length; i++) 
                {
                    Object obj = Array.get(o, i);
                    if (i > 0)
                    {
                        ps.print(",");
                    }
                    print(ps, obj);
                }
            }
            else 
            {
                Object[] objects = (Object[]) o;
                for (int i = 0; i < objects.length; i++)
                {
                    if (i > 0)
                    {
                        ps.print(",");
                    }
                    print(ps, objects[i]);
                }
            }
            ps.print("]");
        }
        else if (o instanceof Collection)
        {
            boolean first = true;
            Collection<?> array = (Collection<?>) o;
            ps.print("[");
            for (Object e : array)
            {
                if (first)
                {
                    first = false;
                }
                else
                {
                    ps.print(",");
                }
                print(ps, e);
            }
            ps.print("]");
        }
        else if (o instanceof Number)
        {
            Number n = (Number) o;
            if (n.intValue() == n.floatValue())
            {
                ps.print(n.intValue());
            }
            else
            {
                ps.print(n.floatValue());
            }
        }
    }
 
    /**
     * Calls {@link #print(PrintStream, Object)} and appends a new line.
     * @param ps The print stream to print to
     * @param o The object
     */
    public static void println(PrintStream ps, Object o)
    {
        print(ps, o);
        ps.println();
    }
    
    /**
     * Creates a simple 5-color gradient. 
     * @param x A fraction between 0 and 1
     * @return A color associated to the fraction, represented as an
     * RGB color in hexadecimal.
     */
    public static String colorGradient(float fraction)
    {
        if (fraction < 0.2)
        {
            return "#0000FF";
        }
        if (fraction < 0.4)
        {
            return "#00FFFF";
        }
        if (fraction < 0.6)
        {
            return "#00FF00";
        }
        if (fraction < 0.8)
        {
            return "#FFFF00";
        }
        return "#FF0000";
    }
}