Java IO.pdf - Nguyen Dang Binh

Java I/O
question is what to do if the input text contains an unescaped backslash. The easiest and most
robust solution is to replace it with \u005C, the Unicode escape for the backslash itself.
Example 15.8. SourceWriter
package com.macfaq.io;
import java.io.*;
public class SourceWriter extends FilterWriter {
{
}
public SourceWriter(Writer out) {
super(out);
}
public void write(char[] text, int offset, int length) throws IOException
}
for (int i = offset; i < offset+length; i++) {
this.write(text[i]);
}
public void write(String s, int offset, int length) throws IOException {
}
for (int i = offset; i < offset+length; i++) {
this.write(s.charAt(i));
}
public void write(int c) throws IOException {
}
// We have to escape the backslashes below.
if (c == '\\') out.write("\\u005C");
else if (c < 128) out.write(c);
else {
String s = Integer.toHexString(c);
// Pad with leading zeroes if necessary.
if (c < 256) s = "00" + s;
else if (c < 4096) s = "0" + s;
out.write("\\u");
out.write(s);
}
15.11.3 PushbackReader
The PushbackReader class is a filter that provides a pushback buffer around a given reader.
This allows a program to "unread" the last character it read. It's similar to
PushbackInputStream , discussed in Chapter 6, but instead of pushing back bytes, it pushes
back chars. Both PushbackReader and BufferedReader use buffers, but only
PushbackReader allows unreading and only BufferedReader allows marking and resetting.
The difference is that pushing back characters allows you to unread characters after the fact.
Marking and resetting requires you to mark in advance the location you want to reset to.
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