/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.codec.net;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import org.apache.commons.codec.Charsets;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.EncoderException;
import org.apache.commons.codec.StringDecoder;
import org.apache.commons.codec.StringEncoder;
import org.apache.commons.codec.binary.Base64;
/**
* Identical to the Base64 encoding defined by <a href="http://www.ietf.org/rfc/rfc1521.txt">RFC 1521</a>
* and allows a character set to be specified.
* <p>
* <a href="http://www.ietf.org/rfc/rfc1522.txt">RFC 1522</a> describes techniques to allow the encoding of non-ASCII
* text in various portions of a RFC 822 [2] message header, in a manner which is unlikely to confuse existing message
* handling software.
* <p>
* This class is immutable and thread-safe.
*
* @see <a href="http://www.ietf.org/rfc/rfc1522.txt">MIME (Multipurpose Internet Mail Extensions) Part Two: Message
* Header Extensions for Non-ASCII Text</a>
*
* @since 1.3
* @version $Id: BCodec.java 1429868 2013-01-07 16:08:05Z ggregory $
*/
public class BCodec extends RFC1522Codec implements StringEncoder, StringDecoder {
/**
* The default charset used for string decoding and encoding.
*/
private final Charset charset;
/**
* Default constructor.
*/
public BCodec() {
this(Charsets.UTF_8);
}
/**
* Constructor which allows for the selection of a default charset
*
* @param charset
* the default string charset to use.
*
* @see <a href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
* @since 1.7
*/
public BCodec(final Charset charset) {
this.charset = charset;
}
/**
* Constructor which allows for the selection of a default charset
*
* @param charsetName
* the default charset to use.
* @throws java.nio.charset.UnsupportedCharsetException
* If the named charset is unavailable
* @since 1.7 throws UnsupportedCharsetException if the named charset is unavailable
* @see <a href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
*/
public BCodec(final String charsetName) {
this(Charset.forName(charsetName));
}
@Override
protected String getEncoding() {
return "B";
}
@Override
protected byte[] doEncoding(final byte[] bytes) {
if (bytes == null) {
return null;
}
return Base64.encodeBase64(bytes);
}
@Override
protected byte[] doDecoding(final byte[] bytes) {
if (bytes == null) {
return null;
}
return Base64.decodeBase64(bytes);
}
/**
* Encodes a string into its Base64 form using the specified charset. Unsafe characters are escaped.
*
* @param value
* string to convert to Base64 form
* @param charset
* the charset for <code>value</code>
* @return Base64 string
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
* @since 1.7
*/
public String encode(final String value, final Charset charset) throws EncoderException {
if (value == null) {
return null;
}
return encodeText(value, charset);
}
/**
* Encodes a string into its Base64 form using the specified charset. Unsafe characters are escaped.
*
* @param value
* string to convert to Base64 form
* @param charset
* the charset for <code>value</code>
* @return Base64 string
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
public String encode(final String value, final String charset) throws EncoderException {
if (value == null) {
return null;
}
try {
return this.encodeText(value, charset);
} catch (final UnsupportedEncodingException e) {
throw new EncoderException(e.getMessage(), e);
}
}
/**
* Encodes a string into its Base64 form using the default charset. Unsafe characters are escaped.
*
* @param value
* string to convert to Base64 form
* @return Base64 string
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
@Override
public String encode(final String value) throws EncoderException {
if (value == null) {
return null;
}
return encode(value, this.getCharset());
}
/**
* Decodes a Base64 string into its original form. Escaped characters are converted back to their original
* representation.
*
* @param value
* Base64 string to convert into its original form
* @return original string
* @throws DecoderException
* A decoder exception is thrown if a failure condition is encountered during the decode process.
*/
@Override
public String decode(final String value) throws DecoderException {
if (value == null) {
return null;
}
try {
return this.decodeText(value);
} catch (final UnsupportedEncodingException e) {
throw new DecoderException(e.getMessage(), e);
}
}
/**
* Encodes an object into its Base64 form using the default charset. Unsafe characters are escaped.
*
* @param value
* object to convert to Base64 form
* @return Base64 object
* @throws EncoderException
* thrown if a failure condition is encountered during the encoding process.
*/
@Override
public Object encode(final Object value) throws EncoderException {
if (value == null) {
return null;
} else if (value instanceof String) {
return encode((String) value);
} else {
throw new EncoderException("Objects of type " +
value.getClass().getName() +
" cannot be encoded using BCodec");
}
}
/**
* Decodes a Base64 object into its original form. Escaped characters are converted back to their original
* representation.
*
* @param value
* Base64 object to convert into its original form
* @return original object
* @throws DecoderException
* Thrown if the argument is not a <code>String</code>. Thrown if a failure condition is encountered
* during the decode process.
*/
@Override
public Object decode(final Object value) throws DecoderException {
if (value == null) {
return null;
} else if (value instanceof String) {
return decode((String) value);
} else {
throw new DecoderException("Objects of type " +
value.getClass().getName() +
" cannot be decoded using BCodec");
}
}
/**
* Gets the default charset name used for string decoding and encoding.
*
* @return the default charset name
* @since 1.7
*/
public Charset getCharset() {
return this.charset;
}
/**
* Gets the default charset name used for string decoding and encoding.
*
* @return the default charset name
*/
public String getDefaultCharset() {
return this.charset.name();
}
}