/*
* Data Hub Service (DHuS) - For Space data distribution.
* Copyright (C) 2016 GAEL Systems
*
* This file is part of DHuS software sources.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package fr.gael.dhus.util.http;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.InterruptibleChannel;
import java.nio.channels.WritableByteChannel;
import java.security.MessageDigest;
import java.util.Objects;
/**
* An {@link InterruptibleChannel} and {@link WritableByteChannel} decorator that submit written
* bytes to the given instance of {@link MessageDigest}.
* <p>Useful to compute MD5/SHA sums while downloading the data.
* @param <IWC> type implementing both InterruptibleChannel and WritableByteChannel.
*/
public class DigestIWC <IWC extends InterruptibleChannel & WritableByteChannel>
implements InterruptibleChannel, WritableByteChannel
{
private final MessageDigest messageDigest;
IWC iwc;
/**
* Constructor.
* @param message_digest a non-null instance to receive written bytes.
* @param iwc a non-null instance to decorate.
*/
public DigestIWC(MessageDigest message_digest, IWC iwc)
{
Objects.requireNonNull(message_digest);
Objects.requireNonNull(iwc);
this.messageDigest = message_digest;
this.iwc = iwc;
}
@Override
public void close() throws IOException
{
this.iwc.close();
}
@Override
public boolean isOpen()
{
return this.iwc.isOpen();
}
@Override
public int write(ByteBuffer src) throws IOException
{
ByteBuffer dup = src.duplicate();
int res = this.iwc.write(src);
this.messageDigest.update(dup);
return res;
}
}