org.eclipse.aether.util.StringDigestUtil Maven / Gradle / Ivy
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* 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.eclipse.aether.util;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* A simple digester utility for Strings. Uses {@link MessageDigest} for requested algorithm. Supports one-pass or
* several rounds of updates, and as result emits hex encoded String.
*
* @since 1.9.0
*/
public final class StringDigestUtil {
private final MessageDigest digest;
/**
* Constructs instance with given algorithm.
*
* @see #sha1()
* @see #sha1(String)
*/
public StringDigestUtil(final String alg) {
try {
this.digest = MessageDigest.getInstance(alg);
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("Not supported digest algorithm: " + alg);
}
}
/**
* Updates instance with passed in string.
*/
public StringDigestUtil update(String data) {
if (data != null && !data.isEmpty()) {
digest.update(data.getBytes(StandardCharsets.UTF_8));
}
return this;
}
/**
* Returns the digest of all strings passed via {@link #update(String)} as hex string. There is no state preserved
* and due implementation of {@link MessageDigest#digest()}, same applies here: this instance "resets" itself.
* Hence, the digest hex encoded string is returned only once.
*
* @see MessageDigest#digest()
*/
public String digest() {
return ChecksumUtils.toHexString(digest.digest());
}
/**
* Helper method to create {@link StringDigestUtil} using SHA-1 digest algorithm.
*/
public static StringDigestUtil sha1() {
return new StringDigestUtil("SHA-1");
}
/**
* Helper method to calculate SHA-1 digest and hex encode it.
*/
public static String sha1(final String string) {
return sha1().update(string).digest();
}
}