Java/Development Class/StringBuilder

Check the capacity of StringBuilder object

 
public class Main {
  public static void main(String[] a) {
    StringBuilder builder1 = new StringBuilder();
    StringBuilder builder2 = new StringBuilder(0);
    StringBuilder builder3 = new StringBuilder(100);
    System.out.println(builder1.capacity());
    System.out.println(builder2.capacity());
    System.out.println(builder3.capacity());
  }
}
/*
16
0
100
*/

Creates StringBuilder objects, append and insert text to them. Use the \n character for line breaks.

 
public class Main {
  public static void main(String[] a) {
    StringBuilder builder = new StringBuilder("Line 1\n");
    builder.append("Line 3\n");
    String lineToInsert = "Line 2\n";
    
    builder.insert(0, lineToInsert);
    System.out.println(builder.toString());
  }
}
/*
Line 2
Line 1
Line 3
*/

Deletes text from the StringBuilder object

 
public class Main {
  public static void main(String[] a) {
    StringBuilder builder = new StringBuilder("Line 1\n");
    builder.append("Line 3\n");
    builder.insert(0, "Line 2\n");
    System.out.println(builder.toString());
    builder = builder.delete(2, 6);
    System.out.println(builder.toString());
  }
}
/*
Line 2
Line 1
Line 3
Li
Line 1
Line 3
*/

Java 1.5 (5.0) new features: StringBuilder

 
/*
License for Java 1.5 "Tiger": A Developer"s Notebook
     (O"Reilly) example package
Java 1.5 "Tiger": A Developer"s Notebook (O"Reilly) 
by Brett McLaughlin and David Flanagan.
ISBN: 0-596-00738-8
You can use the examples and the source code any way you want, but
please include a reference to where it comes from if you use it in
your own products or services. Also note that this software is
provided by the author "as is", with no expressed or implied warranties. 
In no event shall the author be liable for any direct or indirect
damages arising in any way out of the use of this software.
*/
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class StringBuilderTester {
  public static String appendItems(List list) {
    StringBuilder b = new StringBuilder();
    for (Iterator i = list.iterator(); i.hasNext(); ) {
      b.append(i.next())
       .append(" ");
    }
    return b.toString();
  }
  public static void main(String[] args) {
    List list = new ArrayList();
    list.add("I");
    list.add("play");
    list.add("Bourgeois");
    list.add("guitars");
    list.add("and");
    list.add("Huber");
    list.add("banjos");
    System.out.println(StringBuilderTester.appendItems(list));
  }
}

Palindrome with StringBuilder

 
/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  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.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * 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 OWNER 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.
 */
public class Palindrome {
  public static boolean isPalindrome(String stringToTest) {
    String workingCopy = removeJunk(stringToTest);
    String reversedCopy = reverse(workingCopy);
    return reversedCopy.equalsIgnoreCase(workingCopy);
  }
  protected static String removeJunk(String string) {
    int i, len = string.length();
    StringBuilder dest = new StringBuilder(len);
    char c;
    for (i = (len - 1); i >= 0; i--) {
      c = string.charAt(i);
      if (Character.isLetterOrDigit(c)) {
        dest.append(c);
      }
    }
    return dest.toString();
  }
  protected static String reverse(String string) {
    StringBuilder sb = new StringBuilder(string);
    return sb.reverse().toString();
  }
  public static void main(String[] args) {
    String string = "Madam, I"m Adam.";
    System.out.println();
    System.out.println("Testing whether the following "
        + "string is a palindrome:");
    System.out.println("    " + string);
    System.out.println();
    if (isPalindrome(string)) {
      System.out.println("It IS a palindrome!");
    } else {
      System.out.println("It is NOT a palindrome!");
    }
    System.out.println();
  }
}

Remove substring from StringBuilder

 
public class Main {
  public static void main(String[] args) {
    StringBuilder lipsum = new StringBuilder("Lorem ipsum dolor sit amet.");
    System.out.println("lipsum = " + lipsum.toString());
    lipsum.delete(0, 28);
    System.out.println("lipsum = " + lipsum.toString());
    lipsum.deleteCharAt(lipsum.length() - 1);
    System.out.println("lipsum = " + lipsum.toString());
  }
}

StringBuilderDemo: construct the same String three different ways

 
/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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 AUTHOR 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 AUTHOR 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.
 * 
 * Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */
/**
 * StringBuilderDemo: construct the same String three different ways.
 */
public class StringBuilderDemo {
  public static void main(String[] argv) {
    String s1 = "Hello" + ", " + "World";
    System.out.println(s1);
    // Build a StringBuilder, and append some things to it.
    StringBuilder sb2 = new StringBuilder();
    sb2.append("Hello");
    sb2.append(",");
    sb2.append(" ");
    sb2.append("World");
    // Get the StringBuilder"s value as a String, and print it.
    String s2 = sb2.toString();
    System.out.println(s2);
    // Now do the above all over again, but in a more
    // concise (and typical "real-world" Java) fashion.
    StringBuilder sb3 = new StringBuilder().append("Hello").append(",")
        .append(" ").append("World");
    System.out.println(sb3.toString());
  }
}

StringBuilder.reverse

 
/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  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.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * 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 OWNER 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.
 */
public class StringBuilderDemo {
  public static void main(String[] args) {
    String palindrome = "Dot saw I was Tod";
    StringBuilder sb = new StringBuilder(palindrome);
    sb.reverse(); // reverse it
    System.out.println(sb);
  }
}

Use a StringBuilder to Mark Vowel

  
import java.util.Scanner;
public class StringBuilderApp
{
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args)
    {
        System.out.print("Enter a string: ");
        String s = sc.nextLine();
        StringBuilder sb = new StringBuilder(s);
        int vowelCount = 0;
        for (int i = 0; i < s.length(); i++)
        {
            char c = s.charAt(i);
            if (   (c == "A") || (c == "a")
                 || (c == "E") || (c == "e")
                 || (c == "I") || (c == "i")
                 || (c == "O") || (c == "o")
                 || (c == "U") || (c == "u"))
            {
                sb.setCharAt(i,
            }
        }
        System.out.println(s);
        System.out.println(sb.toString());
    }
}