Java tutorial
/* * Copyright 2010, Red Hat, Inc. and individual contributors as indicated by the * @author tags. See the copyright.txt file in the distribution for a full * listing of individual contributors. * * This is free software; you can redistribute it and/or modify it under the * terms of the GNU Lesser General Public License as published by the Free * Software Foundation; either version 2.1 of the License, or (at your option) * any later version. * * This software is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more * details. * * You should have received a copy of the GNU Lesser General Public License * along with this software; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA, or see the FSF * site: http://www.fsf.org. */ package org.zanata.common.io; import java.io.IOException; import java.io.OutputStreamWriter; import java.io.Writer; import java.security.DigestOutputStream; import java.security.MessageDigest; import org.apache.commons.io.output.WriterOutputStream; import com.google.common.base.Charsets; /** * A transparent writer that updates the associated message digest using the * bits going through the writer. * * Writer equivalent of {@link DigestOutputStream} * * @author Carlos Munoz <a * href="mailto:camunoz@redhat.com">camunoz@redhat.com</a> */ public class DigestWriter extends Writer { private OutputStreamWriter digestWriter; public DigestWriter(Writer delegateWriter, MessageDigest digest) { this.digestWriter = new OutputStreamWriter( new DigestOutputStream(new WriterOutputStream(delegateWriter), digest), Charsets.UTF_8); } @Override public void write(char[] cbuf, int off, int len) throws IOException { this.digestWriter.write(cbuf, off, len); } @Override public void flush() throws IOException { this.digestWriter.flush(); } @Override public void close() throws IOException { this.digestWriter.close(); } }