VerifyingWriter.java :  » Science » JabRef-2.6 » net » sf » jabref » export » Java Open Source

package net.sf.jabref.export;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.util.TreeSet;

/**
 * Writer that extends OutputStreamWriter, but also checks if the chosen
 * encoding supports all text that is written. Currently only a boolean value is
 * stored to remember whether everything has gone well or not.
 */
public class VerifyingWriter extends OutputStreamWriter {

  CharsetEncoder encoder;
  private boolean couldEncodeAll = true;
  private TreeSet<Character> problemCharacters = new TreeSet<Character>();

  public VerifyingWriter(OutputStream out, String encoding)
      throws UnsupportedEncodingException {
    super(out, encoding);
    encoder = Charset.forName(encoding).newEncoder();
  }

  public void write(String str) throws IOException {
    super.write(str);
    if (!encoder.canEncode(str)) {
      for (int i = 0; i < str.length(); i++) {
        if (!encoder.canEncode(str.charAt(i)))
          problemCharacters.add(new Character(str.charAt(i)));
      }
      couldEncodeAll = false;
    }
  }

  public boolean couldEncodeAll() {
    return couldEncodeAll;
  }

  public String getProblemCharacters() {
    StringBuffer chars = new StringBuffer();
    for (Character ch : problemCharacters) {
      chars.append(ch.charValue());
    }
    return chars.toString();
  }
}