/*
* JBoss, Home of Professional Open Source
* Copyright 2009, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* Licensed 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.jboss.weld.examples.pastecode.session;
import org.jboss.weld.examples.pastecode.model.CodeFragment;
import javax.ejb.Stateless;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* Compute the hash for a {@link CodeFragment}
*
* @author Martin Gencur
* @author Pete Muir
*/
@Stateless
public class HashComputer {
public String getHashValue(CodeFragment code) throws NoSuchAlgorithmException {
String hashValue;
MessageDigest md = MessageDigest.getInstance("SHA-1");
String combinedValue = code.getText() + code.getDatetime();
md.update(combinedValue.getBytes());
hashValue = asHex(md.digest());
return hashValue;
}
private String asHex(byte[] buf) {
StringBuilder strBuf = new StringBuilder(buf.length * 2);
// make sure it contains a letter!
strBuf.append("h");
for (int i = 0; i < buf.length; i++) {
if ((buf[i] & 0xff) < 0x10) {
strBuf.append("0");
}
strBuf.append(Long.toString(buf[i] & 0xff, 16));
}
if (strBuf.length() <= 6) {
while (strBuf.length() <= 6) {
strBuf.append("0");
}
}
return strBuf.toString().substring(0, 6);
}
}