/*
* Copyright (C) 2011 The original author or authors.
*
* 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 com.zapta.apps.maniana.util;
import java.util.UUID;
import javax.annotation.Nullable;
import com.zapta.apps.maniana.annotations.ApplicationScope;
/**
* Generates universally unique ids.
*
* @author Tal Dayan
*/
@ApplicationScope
public final class IdGenerator {
private static final IdGenerator singleton = new IdGenerator();
/** Prefix common to all ids generated by this instance. */
@Nullable
private String mPrefix = null;
/** Suffix of next generated id. */
private int mCount = 0;
private IdGenerator() {
}
private String internalGetFreshId() {
synchronized (this) {
// Lazy initialization to speed up app start (saves 5-10ms).
if (mPrefix == null) {
mPrefix = UUID.randomUUID().toString() + "-";
}
return mPrefix + mCount++;
}
}
/** Return a fresh globally unique id. Thread safe. */
public static String getFreshId() {
return singleton.internalGetFreshId();
}
}