test/jdk/java/lang/StringBuffer/SBBasher.java

/*
 * Copyright (c) 1998, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @bug 4120694
 * @summary Test new methods in StringBuffer
 * @key randomness
 */

import java.lang.*;
import java.util.*;

public class SBBasher {
    public static void main(String[] args) throws Exception {
        SBBasher basher = new SBBasher();

        for (int iterations=0; iterations<100; iterations++) {
            String testString = basher.generateTestString();
            boolean result = basher.Test1(testString);
            if (result == false)
                throw new RuntimeException("Substring or replace failure.");
        }

        for (int iterations=0; iterations<100; iterations++) {
            String testString = basher.generateTestString();
            boolean result = basher.Test2(testString);
            if (result == false)
                throw new RuntimeException("Insert or delete failure.");
        }

        for (int iterations=0; iterations<100; iterations++) {
            String testString = basher.generateTestString();
            boolean result = basher.Test3(testString);
            if (result == false)
              throw new RuntimeException("Insert, delete or replace failure.");
        }

    }

    private int getRandomIndex(int constraint1, int constraint2) {
        int range = constraint2 - constraint1;
        int x = generator.nextInt();
        return constraint1 + Math.abs(x % range);
    }

    static Random generator = new Random();

    private String generateTestString() {
        StringBuffer aNewString = new StringBuffer(120);
        int aNewLength = getRandomIndex(1,100);
        for(int y=0; y<aNewLength; y++) {
            int achar = generator.nextInt();
            char test = (char)(achar);
            aNewString.append(test);
        }
        return aNewString.toString();
    }

    /**
     * first test, get substring of a random string
     * and replace same spot with same substring
     * then check for equality with original
     * this tests both substrings and the replace method
     */
    private boolean Test1(String before) {
        StringBuffer bashed = new StringBuffer(before);
        String slice;
        for (int i=0; i<100; i++) {
            int startIndex = getRandomIndex(0, before.length());
            int endIndex = getRandomIndex(startIndex, before.length());
            if (endIndex < bashed.length()) {
                slice = bashed.substring(startIndex, endIndex);
            }
            else {
                slice = bashed.substring(startIndex);
            }
            bashed.replace(startIndex, endIndex, slice);
        }
        String after = bashed.toString();
        if (!before.equals(after))
            return false;
        else
            return true;
    }

    /**
     * second test, delete random section of string
     * then insert same section back again
     * then check for equality with original
     * this tests both substrings, both deletes and insert method
     */
    private boolean Test2(String before) {
        StringBuffer bashed = new StringBuffer(before);
        String slice;
        for (int i=0; i<100; i++) {
            int startIndex = getRandomIndex(0, before.length());
            int endIndex = getRandomIndex(startIndex, before.length());
            if (endIndex < bashed.length())
                slice = bashed.substring(startIndex, endIndex);
            else
                slice = bashed.substring(startIndex);
            if (slice.length() == 1)
                bashed.deleteCharAt(startIndex);
            else
                bashed.delete(startIndex, endIndex);
            bashed.insert(startIndex, slice.toCharArray(), 0, slice.length());
        }
        String after = bashed.toString();
        if (!before.equals(after))
            return false;
        else
            return true;
    }

    /**
     * Third test, clone string and make sure that the
     * replace operation is equivalent to a delete followed
     * by an insert with the equivalent arguments
     * this tests replace, delete and insert
     */
    private boolean Test3(String before) {
        StringBuffer bashed1 = new StringBuffer(before);
        StringBuffer bashed2 = new StringBuffer(before);
        int startIndex = getRandomIndex(0, bashed1.length());
        int endIndex = getRandomIndex(startIndex, bashed2.length());

        String insertString = generateTestString();

        bashed1.delete(startIndex, endIndex);
        bashed1.insert(startIndex, insertString);
        bashed2.replace(startIndex, endIndex, insertString);

        String result1 = bashed1.toString();
        String result2 = bashed2.toString();
        if (!result1.equals(result2))
            return false;
        else
            return true;
    }

}