/* | |
* 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.nifi.provenance.journaling.journals; | |
import java.io.IOException; | |
import java.io.InputStream; | |
import java.io.OutputStream; | |
import java.util.Arrays; | |
import org.apache.nifi.stream.io.StreamUtils; | |
public class StandardJournalMagicHeader { | |
private static final byte[] MAGIC_HEADER = "NiFiProvJournal_1".getBytes(); | |
/** | |
* Writes the magic header to the output stream | |
* @param out | |
* @throws IOException | |
*/ | |
static void write(final OutputStream out) throws IOException { | |
out.write(MAGIC_HEADER); | |
} | |
/** | |
* Verifies that the magic header is present on the InputStream | |
* @param in | |
* @throws IOException | |
*/ | |
static void read(final InputStream in) throws IOException { | |
final byte[] magicHeaderBuffer = new byte[MAGIC_HEADER.length]; | |
StreamUtils.fillBuffer(in, magicHeaderBuffer); | |
if ( !Arrays.equals(MAGIC_HEADER, magicHeaderBuffer) ) { | |
throw new IOException("File is not a Journaling Provenance Repository journal file"); | |
} | |
} | |
} |