Java IO.pdf - Nguyen Dang Binh

Example 15.7. SourceReader
package com.macfaq.io;
import java.io.*;
public class SourceReader extends FilterReader {
public SourceReader(InputStream in) {
this(new InputStreamReader(in));
}
public SourceReader(Reader in) {
super(new BufferedReader(in));
}
private int backslashParity = 1;
public int read() throws IOException {
int c = in.read();
if (c != '\\') return c;
backslashParity *= -1;
// If there are an even number of backslashes,
// this is not a Unicode escape.
if (backslashParity == 1) return c;
// Mark is supported because I used
// a BufferedReader in the constructor.
in.mark(1);
int next = in.read();
if (next != 'u' ) { // This is not a Unicode escape
in.reset();
return c;
}
// Read next 4 hex digits.
// If the next four chars do not make a valid hex digit
// this is not a valid .java file and you need a compiler error.
StringBuffer sb = new StringBuffer();
sb.append((char) in.read());
sb.append((char) in.read());
sb.append((char) in.read());
sb.append((char) in.read());
String hex = sb.toString();
try {
return Integer.valueOf(hex, 16).intValue();
}
catch (NumberFormatException e) {
throw new IOException("Bad Unicode escape");
}
}
Java I/O
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