jtulach@63: 
jtulach@63: package org.apidesign.delegatingwriter;
jtulach@63: 
jtulach@63: import java.io.IOException;
jtulach@63: import java.io.Writer;
jtulach@63: 
jtulach@63: /** Writer alters each char from 'A' to 'Z' range with next one just like
jtulach@63:  * old Romans did.
jtulach@63:  *
jtulach@63:  * @author Jaroslav Tulach
jtulach@63:  */
jtulach@63: public class CryptoWriter extends AltBufferedWriter {
jtulach@63:     public CryptoWriter(Writer out) {
jtulach@63:         super(out);
jtulach@63:     }
jtulach@154:     public CryptoWriter(
jtulach@154:         Writer out, AltBufferedWriter.Behaviour behaviour
jtulach@154:     ) {
jtulach@63:         super(out, behaviour);
jtulach@63:     }
jtulach@63: /* The above code is here to let us simulate different behaviours of the append
jtulach@63:  * method. In reality, the class would just subclass BufferedWriter, as shown bellow:
jtulach@63: BEGIN: writer.CryptoWriter
jtulach@63: public class CryptoWriter extends BufferedWriter {
jtulach@63:     public CryptoWriter(Writer out) {
jtulach@63:         super(out);
jtulach@63:     }
jtulach@63:     
jtulach@154:     /* We need to override all known methods of BufferedWriter 
jtulach@154:     * and do conversion of the argument char, string or char array.
jtulach@63:     */
jtulach@63:     
jtulach@63:     @Override
jtulach@154:     public void write(char[] buf, int off, int len) throws IOException {
jtulach@63:         char[] arr = new char[len];
jtulach@63:         for (int i = 0; i < len; i++) {
jtulach@210:             arr[i] = encryptChar(buf[off + i]);
jtulach@63:         }
jtulach@63:         super.write(arr, 0, len);
jtulach@63:     }
jtulach@63: 
jtulach@63:     @Override
jtulach@63:     public void write(int c) throws IOException {
jtulach@210:         super.write(encryptChar(c));
jtulach@63:     }
jtulach@63: 
jtulach@63:     @Override
jtulach@63:     public void write(String str, int off, int len) throws IOException {
jtulach@63:         StringBuffer sb = new StringBuffer();
jtulach@63:         for (int i = 0; i < len; i++) {
jtulach@210:             sb.append(encryptChar(str.charAt(off + i)));
jtulach@63:         }
jtulach@63:         super.write(sb.toString(), 0, len);
jtulach@63:     }
jtulach@63: 
jtulach@210:     private char encryptChar(int c) {
jtulach@63:         if (c == 'Z') {
jtulach@63:             return 'A';
jtulach@63:         }
jtulach@63:         if (c == 'z') {
jtulach@63:             return 'a';
jtulach@63:         }
jtulach@63:         return (char)(c + 1);
jtulach@63:     }
jtulach@181: // FINISH: writer.CryptoWriter
jtulach@63: 
jtulach@63:     /* delegates to write(cbuf, 0, cbuf.length)
jtulach@63:     public void write(char[] cbuf) throws IOException {
jtulach@63:     }
jtulach@63:     */
jtulach@63: 
jtulach@63:     /* delegates to write(str, 0, str.length())
jtulach@63:     public void write(String str) throws IOException {
jtulach@63:     }
jtulach@63:     */
jtulach@63: 
jtulach@63:     
jtulach@63: /* As this class was written against the version provided by JDK 1.4, we
jtulach@63:  * could not override the append methods, as they did not exist at that time.
jtulach@63:      
jtulach@63:     @Override
jtulach@63:     public Writer append(CharSequence csq) throws IOException {
jtulach@63:     }
jtulach@63: 
jtulach@63:     @Override
jtulach@63:     public Writer append(CharSequence csq, int start, int end) throws IOException {
jtulach@63:     }
jtulach@63: 
jtulach@63:     @Override
jtulach@63:     public Writer append(char c) throws IOException {
jtulach@63:     }
jtulach@63: */
jtulach@63:     
jtulach@63: }