opennlp.tools.ml.model.HashSumEventStream Maven / Gradle / Ivy
/*
* 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 opennlp.tools.ml.model;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import opennlp.tools.util.AbstractObjectStream;
import opennlp.tools.util.ObjectStream;
public class HashSumEventStream extends AbstractObjectStream {
private MessageDigest digest;
public HashSumEventStream(ObjectStream eventStream) {
super(eventStream);
try {
digest = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
// should never happen, does all java runtimes have md5 ?!
throw new IllegalStateException(e);
}
}
@Override
public Event read() throws IOException {
Event event = super.read();
if (event != null) {
digest.update(event.toString().getBytes(StandardCharsets.UTF_8));
}
return event;
}
/**
* Calculates the hash sum of the stream. The method must be
* called after the stream is completely consumed.
*
* @return the hash sum
* @throws IllegalStateException if the stream is not consumed completely,
* completely means that hasNext() returns false
*/
public BigInteger calculateHashSum() {
return new BigInteger(1, digest.digest());
}
public void remove() {
}
}