/**
* Licensed to JumpMind Inc under one or more contributor
* license agreements. See the NOTICE file distributed
* with this work for additional information regarding
* copyright ownership. JumpMind Inc licenses this file
* to you under the GNU General Public License, version 3.0 (GPLv3)
* (the "License"); you may not use this file except in compliance
* with the License.
*
* You should have received a copy of the GNU General Public License,
* version 3.0 (GPLv3) along with this library; if not, see
* <http://www.gnu.org/licenses/>.
*
* 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.jumpmind.util;
import java.util.Random;
/**
* Use runtime configuration specific seeding to get a random number for use in
* time slotting nodes to help stagger load.
*/
public class RandomTimeSlot {
int maxValue = -1;
Random random;
public RandomTimeSlot() {
random = new Random();
}
public RandomTimeSlot(String externalId, int maxValue) {
this.maxValue = maxValue;
random = new Random(fromExternalId(externalId));
}
private long fromExternalId(String externalId) {
if (externalId != null) {
return Math.abs(externalId.hashCode());
} else {
return Integer.MAX_VALUE;
}
}
public int getRandomValueSeededByExternalId() {
int nextValue = random.nextInt(maxValue);
return nextValue == 0 ? 1 : nextValue;
}
}