geode-core/src/test/java/org/apache/geode/internal/UniqueIdGeneratorJUnitTest.java

/*
 * 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.apache.geode.internal;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

import org.junit.Test;


/**
 * Tests UniqueIdGenerator.
 *
 * @since GemFire 5.0.2 (cbb5x_PerfScale)
 */
public class UniqueIdGeneratorJUnitTest {

  @Test
  public void testBasics() throws Exception {
    UniqueIdGenerator uig = new UniqueIdGenerator(1);
    assertEquals(0, uig.obtain());
    try {
      uig.obtain();
      fail("expected IllegalStateException");
    } catch (IllegalStateException expected) {
    }
    uig.release(0);
    assertEquals(0, uig.obtain());

    uig = new UniqueIdGenerator(32768);
    for (int i = 0; i < 32768; i++) {
      assertEquals(i, uig.obtain());
    }
    try {
      uig.obtain();
      fail("expected IllegalStateException");
    } catch (IllegalStateException expected) {
    }
    for (int i = 32767; i >= 0; i--) {
      uig.release(i);
      assertEquals(i, uig.obtain());
    }
  }
}