package org.apidesign.delegatingwriter;

import java.io.IOException;

import java.io.Writer;

/** Writer alters each char from 'A' to 'Z' range with next one just like

 * old Romans did.

 *

 * @author Jaroslav Tulach

 */

public class CryptoWriter extends AltBufferedWriter {

    public CryptoWriter(Writer out) {

        super(out);

    }

    public CryptoWriter(

        Writer out, AltBufferedWriter.Behaviour behaviour

    ) {

        super(out, behaviour);

    }

/* The above code is here to let us simulate different behaviours of the append

 * method. In reality, the class would just subclass BufferedWriter, as shown bellow:

BEGIN: writer.CryptoWriter

public class CryptoWriter extends BufferedWriter {

    public CryptoWriter(Writer out) {

        super(out);

    }

    /* We need to override all known methods of BufferedWriter 

    * and do conversion of the argument char, string or char array.

    */

    @Override

    public void write(char[] buf, int off, int len) throws IOException {

        char[] arr = new char[len];

        for (int i = 0; i < len; i++) {

            arr[i] = encryptChar(buf[off + i]);

        }

        super.write(arr, 0, len);

    }

    @Override

    public void write(int c) throws IOException {

        super.write(encryptChar(c));

    }

    @Override

    public void write(String str, int off, int len) throws IOException {

        StringBuffer sb = new StringBuffer();

        for (int i = 0; i < len; i++) {

            sb.append(encryptChar(str.charAt(off + i)));

        }

        super.write(sb.toString(), 0, len);

    }

    private char encryptChar(int c) {

        if (c == 'Z') {

            return 'A';

        }

        if (c == 'z') {

            return 'a';

        }

        return (char)(c + 1);

    }

// FINISH: writer.CryptoWriter

    /* delegates to write(cbuf, 0, cbuf.length)

    public void write(char[] cbuf) throws IOException {

    }

    */

    /* delegates to write(str, 0, str.length())

    public void write(String str) throws IOException {

    }

    */

/* As this class was written against the version provided by JDK 1.4, we

 * could not override the append methods, as they did not exist at that time.

    @Override

    public Writer append(CharSequence csq) throws IOException {

    }

    @Override

    public Writer append(CharSequence csq, int start, int end) throws IOException {

    }

    @Override

    public Writer append(char c) throws IOException {

    }

*/

}