Java Random String getRandomString(Random random, int totalLength, int randomSectionLength)

Description

Naive implementation - come up with something smarter.

License

Apache License

Parameter

Parameter	Description
totalLength	- the total length of the string.
randomSectionLength	- the length of the random section of the string. If randomSectionLength is smaller than totalLength, the final string consists in identical repeated sections; the section that will be repeated is 'randomSectionLength' long and it is randomly generated.

Declaration

public static String getRandomString(Random random, int totalLength, int randomSectionLength) 

Method Source Code

//package com.java2s;
/*/*from ww w  .  ja  v  a2s .  c  om*/
 * Copyright (c) 2015 Nova Ordis LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.Random;

public class Main {
    /**
     * Naive implementation - come up with something smarter.
     *
     * @param totalLength - the total length of the string.
     * @param randomSectionLength - the length of the random section of the string. If randomSectionLength
     *       is smaller than totalLength, the final string consists in identical repeated sections; the section that
     *       will be repeated is 'randomSectionLength' long and it is randomly generated.
     */
    public static String getRandomString(Random random, int totalLength, int randomSectionLength) {
        String randomSection = "";
        int r;

        if (totalLength < randomSectionLength) {
            randomSectionLength = totalLength;
        }

        if (randomSectionLength <= 0) {
            throw new IllegalArgumentException("invalid length " + randomSectionLength);
        }

        for (int i = 0; i < randomSectionLength; i++) {
            r = random.nextInt(122);

            if (r >= 0 && r <= 25) {
                r += 65;
            } else if (r >= 26 && r <= 47) {
                r += 71;
            } else if (r >= 58 && r <= 64) {
                r += 10;
            } else if (r >= 91 && r <= 96) {
                r += 10;
            }
            //            else if ((r >=48 && r <=57) || (r >=65 && r <=90) || (r >=97 && r <=122))
            //            {
            //                // nothing, we're good
            //            }

            randomSection += ((char) r);
        }

        if (totalLength == randomSectionLength) {
            return randomSection;
        } else if (totalLength > randomSectionLength) {
            char[] src = randomSection.toCharArray();
            int sections = totalLength / randomSectionLength;
            char[] buffer = new char[totalLength];
            for (int i = 0; i < sections; i++) {
                System.arraycopy(src, 0, buffer, i * randomSectionLength, randomSectionLength);
            }
            int rest = totalLength - sections * randomSectionLength;
            System.arraycopy(src, 0, buffer, sections * randomSectionLength, rest);
            return new String(buffer);
        }

        throw new RuntimeException("NOT YET IMPLEMENTED");
    }
}

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4. getRandomString(int strLength)
5. getRandomString(Random random, int minLen, int maxLen)
6. getRandomString(Random rnd, int minLength, int maxLength)
7. getRandomString(String paramString, int paramLength)
8. getRandomStringByLength(int length)
9. getRandomStringForDate()