at.spardat.enterprise.test.TestUtil Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of epbase Show documentation
There is a newer version: 6.0.2
/*******************************************************************************
 * Copyright (c) 2003, 2007 s IT Solutions AT Spardat GmbH .
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     s IT Solutions AT Spardat GmbH - initial API and implementation
 *******************************************************************************/

package at.spardat.enterprise.test;

import java.io.FileReader;
import java.io.FileWriter;
import java.util.Random;

/**
 * Provides some utility-Methods to generate test-data. Contains a random
 * number generator, which is able to reproduce the same sequence of random numbers
 * over multiple runs of an application, dependent on a system property.
 */
public class TestUtil {

    /**
     * Generiert einen String einer besimmten L?nge mit zuf?lligen
     * Ziffern-Inhalt.
     *
     * @param len die L?nge des Returnwerts
     * @return String der L?nge len der nur aus Ziffern besteht.
     */
    public static String randomDigitString (int len) {
        StringBuffer        b = new StringBuffer(len);
        for (int i=0; ilen aus [a-z].
     */
    public static String randomString (int len) {
        StringBuffer        b = new StringBuffer(len);
        for (int i=0; iLASTSEED, it is seeded by an number read
     * from the file lastseed.txt or the seed is taken from the current
     * time and written to the file. 
     *
     * Thereby we are able to reproduce a sequence of random numbers
     * over multiple runs of a JUnit testRunner.
     */
    private synchronized static Random getRandom () {
        if (random_ == null) {
            // look up system property LASTSEED
            if (System.getProperty("LASTSEED") == null) {
                // create Random-Generator based on current time
                long        time = System.currentTimeMillis();
                try {
                    writeSeedToFile(time);
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
                random_ = new Random(time);
            } else {
                // get the last seed from file
                long        seed = 0;
                try {
                    seed = getLastSeedFromFile();
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
                random_ = new Random(seed);
            }
        }
        return random_;
    }

    private static String       SEED_FILE = "lastSeed.txt";

    /**
     * Returns the last seed written to the file lastSeed.txt
     */
    private static long getLastSeedFromFile () throws Exception {
        FileReader          fr = new FileReader(SEED_FILE);
        StringBuffer        buf = new StringBuffer();
        int                 lastChar;
        while ((lastChar = fr.read()) != -1)
            buf.append((char)lastChar);
        fr.close();
        return Long.parseLong(buf.toString());
    }

    /**
     * Writes the seed to the file lastSeed.txt
     */
    private static void writeSeedToFile(long seed) throws Exception {
        FileWriter          fw = new FileWriter(SEED_FILE);
        fw.write(String.valueOf(seed));
        fw.close();
    }

}