URL.java

/*
 * Copyright (C) 2014 Maigret Aurelien / Colin Julien
 *
 * This program 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 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package fr.qinder.tools;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

/**
 * Utility class for edit an URL.
 * 
 * @author Maigret Aurelien
 * @author Colin Julien
 */
public final class URL {

    /**
     * Constructor, not called, because this is an Utility Class.
     */
    private URL() {
    }

    /**
     * Get the separator
     * 
     * @param url
     *            String of the URL
     * @return The URL with this additional parameter
     */
    private static Character getSeparator(String url) {
        Character sep;

        if (url.indexOf('?') == -1) {
            sep = '?';
        } else {
            sep = '&';
        }
        return sep;
    }

    /**
     * Add a string before the hash in an URL.
     * 
     * @param url
     *            String of the URL
     * @param newParameter
     *            String of the new parameter
     * @return The URL with the new parameter
     */
    private static String addStringBeforeHash(String url, String newParameter) {
        int indexHash = url.indexOf('#');
        String res;

        if (indexHash == -1) {
            res = url + newParameter;
        } else {
            res = url.substring(0, indexHash) + newParameter + url.substring(indexHash);
        }
        return res;
    }

    /**
     * Add a parameter to an URL.
     * 
     * @param url
     *            String of the URL
     * @param key
     *            String of the key
     * @param value
     *            String of the value for this key
     * @return The URL with this additional parameter
     */
    public static String addParameter(String url, String key, String value) {
        String newParameter;
        try {
            newParameter = getSeparator(url) + URLEncoder.encode(key, "UTF-8") + '=' + URLEncoder.encode(value, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            newParameter = "";
        }
        return addStringBeforeHash(url, newParameter);
    }

}