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samples/delegatingwriterfinal/src-api2.0/api/Writer.java
author Jaroslav Tulach <jtulach@netbeans.org>
Sat, 14 Jun 2008 10:04:53 +0200
changeset 210 acf2c31e22d4
parent 209 1c999569643b
permissions -rw-r--r--
Merge: Geertjan's changes to the end of the chapter 
     1 package api;

     2 

     3 import java.io.IOException;

     4 

     5 /** Fixing the problem caused by mixing subclassing and delegation in 

     6  * the <code>java.io.BufferedWriter</code>

     7  *

     8  * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>

     9  */

    10 // BEGIN: writer.final.2.0

    11 public final class Writer implements Appendable {

    12     private final Impl impl;

    13     private final ImplSeq seq;

    14     

    15     private Writer(Impl impl, ImplSeq seq) {

    16         this.impl = impl;

    17         this.seq = seq;

    18     }

    19     public final void write(int c) throws IOException {

    20         if (impl != null) {

    21             char[] arr = {(char) c};

    22             impl.write(arr, 0, 1);

    23         } else {

    24             seq.write(new CharSeq(c));

    25         }

    26     }

    27     

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

    29         if (impl != null) {

    30             impl.write(cbuf, 0, cbuf.length);

    31         } else {

    32             seq.write(new CharSeq(cbuf, 0, cbuf.length));

    33         }

    34     }

    35     public final void write(char cbuf[], int off, int len) 

    36     throws IOException {

    37         if (impl != null) {

    38             impl.write(cbuf, off, len);

    39         } else {

    40             seq.write(new CharSeq(cbuf, off, len));

    41         }

    42     }

    43     public final void write(String str) throws IOException {

    44         if (impl != null) {

    45             impl.write(str, 0, str.length());

    46         } else {

    47             seq.write(str);

    48         }

    49     }

    50     public final void write(String str, int off, int len) 

    51     throws IOException {

    52         if (impl != null) {

    53             impl.write(str, off, len);

    54         } else {

    55             seq.write(str.subSequence(off, off + len));

    56         }

    57     }

    58 

    59     public final void flush() throws IOException {

    60         if (impl != null) {

    61             impl.flush();

    62         } else {

    63             seq.flush();

    64         }

    65     }

    66     public final void close() throws IOException {

    67         if (impl != null) {

    68             impl.close();

    69         } else {

    70             seq.flush();

    71         }

    72     }

    73 

    74     

    75     

    76     public final Writer append(CharSequence csq) throws IOException {

    77         if (impl != null) {

    78             String s = csq == null ? "null" : csq.toString();

    79             impl.write(s, 0, s.length());

    80         } else {

    81             seq.write(csq);

    82         }

    83         return this;

    84     }

    85 

    86     public final Writer append(CharSequence csq, int start, int end) 

    87     throws IOException {

    88         return append(csq.subSequence(start, end));

    89     }

    90 

    91     public final Writer append(char c) throws IOException {

    92         write(c);

    93         return this;

    94     }

    95 

    96     public static Writer create(Impl impl) {

    97         return new Writer(impl, null);

    98     }

    99 

   100     public static Writer create(ImplSeq seq) {

   101         return new Writer(null, seq);

   102     }

   103     

   104     public static Writer create(final java.io.Writer w) {

   105         return new Writer(null, new ImplSeq() {

   106             public void write(CharSequence seq) throws IOException {

   107                 w.append(seq);

   108             }

   109 

   110             public void close() throws IOException {

   111                 w.close();

   112             }

   113 

   114             public void flush() throws IOException {

   115                 w.flush();

   116             }

   117         });

   118     }

   119     

   120     public static Writer createBuffered(final Writer out) {

   121         return create(new SimpleBuffer(out));

   122     }

   123     

   124     

   125     public static interface Impl {

   126         public void close() throws IOException;

   127         public void flush() throws IOException;

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

   129         public void write(char[] arr, int off, int len) throws IOException;

   130     }

   131     public static interface ImplSeq {

   132         public void close() throws IOException;

   133         public void flush() throws IOException;

   134         public void write(CharSequence seq) throws IOException;

   135     }

   136 }

   137 // END: writer.final.2.0
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