/**
* Applies an RFC 1522 compliant encoding scheme to the given string of text with the given
* charset.
*
* <p>This method constructs the "encoded-word" header common to all the RFC 1522 codecs and then
* invokes {@link #getEncoded(byte [])} method of a concrete class to perform the specific
* encoding.
*
* @param sText a string to encode
* @param aSourceCharset a charset to be used
* @return RFC 1522 compliant "encoded-word"
* @throws EncodeException thrown if there is an error condition during the Encoding process.
* @see <a
* href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
* charsets</a>
*/
@Nullable
protected String getEncodedText(
@Nullable final String sText, @Nonnull final Charset aSourceCharset) throws EncodeException {
ValueEnforcer.notNull(aSourceCharset, "SourceCharset");
if (sText == null) return null;
final byte[] aEncodedData = getEncoded(CharsetManager.getAsBytes(sText, aSourceCharset));
final StringBuilder aSB = new StringBuilder();
aSB.append(PREFIX)
.append(aSourceCharset.name())
.append(SEP)
.append(getRFC1522Encoding())
.append(SEP)
.append(CharsetManager.getAsString(aEncodedData, CCharset.CHARSET_US_ASCII_OBJ))
.append(POSTFIX);
return aSB.toString();
}
/**
* Applies an RFC 1522 compliant decoding scheme to the given string of text.
*
* <p>This method processes the "encoded-word" header common to all the RFC 1522 codecs and then
* invokes {@link #getDecoded(byte [])} method of a concrete class to perform the specific
* decoding.
*
* @param sEncodedText a string to decode
* @return A new decoded String or {@code null} if the input is {@code null}.
* @throws DecodeException thrown if there is an error condition during the decoding process.
*/
@Nullable
public String getDecodedText(@Nullable final String sEncodedText) throws DecodeException {
if (sEncodedText == null) return null;
ValueEnforcer.isTrue(
sEncodedText.startsWith(PREFIX),
"RFC 1522 violation: malformed encoded content. Prefix missing.");
ValueEnforcer.isTrue(
sEncodedText.endsWith(POSTFIX),
"RFC 1522 violation: malformed encoded content. Postfix missing.");
int nFrom = PREFIX.length();
final int nTerminator = sEncodedText.length() - POSTFIX.length();
// Read charset
int nTo = sEncodedText.indexOf(SEP, nFrom);
if (nTo == nTerminator)
throw new DecodeException("RFC 1522 violation: charset token not found");
final String sDestCharset = sEncodedText.substring(nFrom, nTo);
if (StringHelper.hasNoText(sDestCharset))
throw new DecodeException("RFC 1522 violation: charset not specified");
final Charset aDestCharset = CharsetManager.getCharsetFromNameOrNull(sDestCharset);
if (aDestCharset == null)
throw new DecodeException("Failed to resolve charset '" + sDestCharset + "'");
// Read encoding
nFrom = nTo + 1;
nTo = sEncodedText.indexOf(SEP, nFrom);
if (nTo == nTerminator)
throw new DecodeException("RFC 1522 violation: encoding token not found");
final String sEncoding = sEncodedText.substring(nFrom, nTo);
if (!getRFC1522Encoding().equalsIgnoreCase(sEncoding))
throw new DecodeException("This codec cannot decode '" + sEncoding + "' encoded content");
// Read encoded data
nFrom = nTo + 1;
nTo = sEncodedText.indexOf(SEP, nFrom);
final byte[] aEncodedBytes =
CharsetManager.getAsBytes(
sEncodedText.substring(nFrom, nTo), CCharset.CHARSET_US_ASCII_OBJ);
final byte[] aDecodedBytes = getDecoded(aEncodedBytes);
return CharsetManager.getAsString(aDecodedBytes, aDestCharset);
}