Java tutorial
/** * Copyright (c) Codice Foundation * <p> * 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 3 of the * License, or any later version. * <p> * 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 * Lesser General Public License for more details. A copy of the GNU Lesser General Public License * is distributed along with this program and can be found at * <http://www.gnu.org/licenses/lgpl.html>. */ package org.codice.ddf.checksum.impl; import java.io.IOException; import java.io.InputStream; import java.util.zip.CRC32; import java.util.zip.Checksum; import org.apache.commons.io.IOUtils; import org.codice.ddf.checksum.AbstractChecksumProvider; import org.slf4j.LoggerFactory; import org.slf4j.ext.XLogger; public class CRC32ChecksumProvider extends AbstractChecksumProvider { private static final String DIGEST_ALGORITHM = "CRC32"; private static final XLogger LOGGER = new XLogger(LoggerFactory.getLogger(CRC32ChecksumProvider.class)); @Override public String calculateChecksum(InputStream inputStream) throws IOException { if (inputStream == null) { throw new IllegalArgumentException("InputStream cannot be null"); } byte[] bytes = IOUtils.toByteArray(inputStream); Checksum checksum = new CRC32(); checksum.update(bytes, 0, bytes.length); long checkSumValue = checksum.getValue(); return Long.toHexString(checkSumValue); } @Override public String getChecksumAlgorithm() { return DIGEST_ALGORITHM; } }