/*
* Syncany, www.syncany.org
* Copyright (C) 2011-2015 Philipp C. Heckel <philipp.heckel@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.syncany.database;
import java.security.SecureRandom;
import java.util.Arrays;
import org.syncany.util.StringUtil;
/**
* The object ID is a generic identifier used by the database entities.
* As of now, it uses a byte array internally, but could also use different
* more memory-preserving methods (such as two longs).
*
* @author Fabrice Rossi <fabrice.rossi@apiacoa.org>
*/
public abstract class ObjectId {
private static SecureRandom secureRng = new SecureRandom();
protected byte[] identifier;
public ObjectId(byte[] identifier) {
if (identifier == null) {
throw new IllegalArgumentException("Argument 'identifier' cannot be null.");
}
this.identifier = identifier;
}
/**
* Returns the raw representation of the object identifier in the
* form of a byte array.
*/
public byte[] getBytes() {
return Arrays.copyOf(identifier, identifier.length);
}
/**
* Converts the byte-array based identifier to a lower
* case hex string and returns this string.
*/
@Override
public String toString() {
return StringUtil.toHex(identifier);
}
public static byte[] parseObjectId(String s) {
if (s == null) {
throw new IllegalArgumentException("Argument 's' cannot be null.");
}
return StringUtil.fromHex(s);
}
public static byte[] secureRandomBytes(int size) {
byte[] newRandomBytes = new byte[size];
synchronized (secureRng) {
secureRng.nextBytes(newRandomBytes);
}
return newRandomBytes;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + Arrays.hashCode(identifier);
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (!(obj instanceof ObjectId)) {
return false;
}
ObjectId other = (ObjectId) obj;
if (!Arrays.equals(identifier, other.identifier)) {
return false;
}
return true;
}
}