SyMATPadViewer/src/com/netsyms/symat/padview/FileUtils.java

/* 
 * Copyright (c) 2015, Netsyms Technologies
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package com.netsyms.symat.padview;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Scanner;
import javax.swing.JFileChooser;
import javax.swing.filechooser.FileNameExtensionFilter;

/**
 * File Utilities.
 *
 * @author Skylar
 */
public class FileUtils {

    /**
     * Read a UTF-8 text file.
     *
     * @param path Where is the file?
     * @return The file contents.
     * @throws IOException
     */
    public static String readFile(String path)
            throws IOException {
        byte[] encoded = Files.readAllBytes(Paths.get(path));
        return new String(encoded, StandardCharsets.UTF_8);
    }

    /**
     * Returns the selected file from a JFileChooser, including the extension
     * from the file filter.
     *
     * Credit to http://stackoverflow.com/users/964243/boann
     *
     * @param c The JFileChooser to extract from.
     * @return duh.
     */
    public static File getFileWithExtension(JFileChooser c) {
        File file = c.getSelectedFile();
        if (c.getFileFilter() instanceof FileNameExtensionFilter) {
            String[] exts = ((FileNameExtensionFilter) c.getFileFilter()).getExtensions();
            String nameLower = file.getName().toLowerCase();
            for (String ext : exts) { // check if it already has a valid extension
                if (nameLower.endsWith('.' + ext.toLowerCase())) {
                    return file; // if yes, return as-is
                }
            }
            // if not, append the first extension from the selected filter
            file = new File(file.toString() + '.' + exts[0]);
        }
        return file;
    }

    public static void saveFile(String content, String path, boolean addToRecent)
            throws IOException {
        try (PrintStream out = new PrintStream(new FileOutputStream(path))) {
            out.print(content);
        }
    }

    /**
     * Get an MD5 hash.
     *
     * http://stackoverflow.com/a/6565597/2534036
     *
     * @param md5 the text to hash.
     * @return
     */
    public static String MD5(String md5) {
        try {
            java.security.MessageDigest md
                    = java.security.MessageDigest.getInstance("MD5");
            byte[] array = md.digest(md5.getBytes());
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < array.length; ++i) {
                sb.append(Integer.toHexString((array[i] & 0xFF) | 0x100).substring(1, 3));
            }
            return sb.toString();
        } catch (java.security.NoSuchAlgorithmException e) {
        }
        return null;
    }

    public static String getUrl(String url) throws MalformedURLException, IOException {
        String out;
        try (Scanner sc = new Scanner(new URL(url).openStream(), "UTF-8")) {
            out = sc.useDelimiter("\\A").next();
        }
        return out;
    }
}