/* * 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. */ // CharSequenceDemo presents a String value -- backwards.public class CharSequenceDemo implements CharSequence {    private String s;    public CharSequenceDemo(String s) {        //It would be much more efficient to just reverse the string        //in the constructor. But a lot less fun!        this.s = s;    }    //If the string is backwards, the end is the beginning!    private int fromEnd(int i) {        return s.length() - 1 - i;    }    public char charAt(int i) {        if ((i < 0) || (i >= s.length())) {            throw new StringIndexOutOfBoundsException(i);        }        return s.charAt(fromEnd(i));    }    public int length() {        return s.length();    }    public CharSequence subSequence(int start, int end) {        if (start < 0) {            throw new StringIndexOutOfBoundsException(start);        }        if (end > s.length()) {            throw new StringIndexOutOfBoundsException(end);        }        if (start > end) {            throw new StringIndexOutOfBoundsException(start - end);        }        StringBuilder sub =             new StringBuilder(s.subSequence(fromEnd(end), fromEnd(start)));        return sub.reverse();    }    public String toString() {        StringBuilder s = new StringBuilder(this.s);        return s.reverse().toString();    }    //Random int from 0 to max.    private static int random(int max) {        return (int) Math.round(Math.random() * max + 0.5);    }    public static void main(String[] args) {        CharSequenceDemo s =            new CharSequenceDemo("Write a class that implements the CharSequence interface found in the java.lang package.");        //exercise charAt() and length()        for (int i = 0; i < s.length(); i++) {            System.out.println(s.charAt(i));        }        //exercise subSequence() and length();        int start = random(s.length() - 1);        int end = random(s.length() - 1 - start) + start;        System.out.println(s.subSequence(start, end));        //exercise toString();        System.out.println(s);    }}