Java tutorial
/* * Copyright 2010 Jose Antonio Jamilena Daza * * Licensed 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 es.jamisoft.comun.codec; //~--- non-JDK imports -------------------------------------------------------- import es.jamisoft.comun.codec.exceptions.B64DecoderException; import es.jamisoft.comun.codec.exceptions.B64EncoderException; import org.apache.commons.codec.CharEncoding; import org.apache.commons.codec.DecoderException; import org.apache.commons.codec.EncoderException; import org.apache.commons.codec.binary.Base64; import org.apache.commons.codec.net.BCodec; //~--- JDK imports ------------------------------------------------------------ import java.io.UnsupportedEncodingException; //~--- classes ---------------------------------------------------------------- /** * <p> * 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> * * <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> * * @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> * * @author Apache Software Foundation * @since 1.3 * @version $Id: BCodec.java 797857 2009-07-25 23:43:33Z ggregory $ * * B64Codec * @author Jose Antonio Jamilena Daza */ public class B64Codec extends BCodec { /** * The default charset used for string decoding and encoding. */ private final String charset; //~--- constructors ------------------------------------------------------- /** * Default constructor. */ public B64Codec() { this(CharEncoding.UTF_8); } /** * Constructor which allows for the selection of a default charset * * @param charset * the default string charset to use. * * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Standard charsets</a> */ public B64Codec(final String charset) { super(); this.charset = charset; } //~--- get methods -------------------------------------------------------- protected String getEncoding() { return "B64Codec"; } //~--- methods ------------------------------------------------------------ protected byte[] doEncoding(byte[] bytes) { if (bytes == null) { return null; } return Base64.encodeBase64(bytes); } protected byte[] doDecoding(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 B64EncoderException * thrown if a failure condition is encountered during the encoding process. */ public String encode(final String value, final String charset) throws B64EncoderException { if (value == null) { return null; } try { return encodeText(value, charset); } catch (Exception e) { throw new B64EncoderException(e.getMessage()); } } /** * 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 B64EncoderException * thrown if a failure condition is encountered during the encoding process. */ public String encode(String value) throws B64EncoderException { if (value == null) { return null; } return encode(value, getDefaultCharset()); } /** * 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 B64DecoderException * A decoder exception is thrown if a failure condition is encountered during the decode process. */ public String decode(String value) throws B64DecoderException { if (value == null) { return null; } try { return decodeText(value); } catch (Exception e) { throw new B64DecoderException(e.getMessage()); } } /** * 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. */ public Object encode(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. */ public Object decode(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"); } } //~--- get methods -------------------------------------------------------- /** * The default charset used for string decoding and encoding. * * @return the default string charset. */ public String getDefaultCharset() { return this.charset; } }