/*
    * Copyright (C) 2007 The Guava 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.google.common.collect;
  
  import com.google.common.base.Function;
  import com.google.common.testing.GcFinalization;
  import com.google.common.testing.NullPointerTester;
  
  import junit.framework.TestCase;
  
  import java.lang.ref.WeakReference;
  
  /**
   * Unit test for {@link Interners}.
   *
   * @author Kevin Bourrillion
   */
  public class InternersTest extends TestCase {
  
    public void testStrong_simplistic() {
      String canonical = "a";
      String not = new String("a");
  
      Interner<String> pool = Interners.newStrongInterner();
      assertSame(canonical, pool.intern(canonical));
      assertSame(canonical, pool.intern(not));
    }
  
    public void testStrong_null() {
      Interner<String> pool = Interners.newStrongInterner();
      try {
        pool.intern(null);
        fail();
      } catch (NullPointerException ok) {}
    }
  
    public void testWeak_simplistic() {
      String canonical = "a";
      String not = new String("a");
  
      Interner<String> pool = Interners.newWeakInterner();
      assertSame(canonical, pool.intern(canonical));
      assertSame(canonical, pool.intern(not));
    }
  
    public void testWeak_null() {
      Interner<String> pool = Interners.newWeakInterner();
      try {
        pool.intern(null);
        fail();
      } catch (NullPointerException ok) {}
    }
  
    public void testWeak_afterGC() throws InterruptedException {
      Integer canonical = new Integer(5);
      Integer not = new Integer(5);
  
      Interner<Integer> pool = Interners.newWeakInterner();
      assertSame(canonical, pool.intern(canonical));
  
      WeakReference<Integer> signal = new WeakReference<Integer>(canonical);
      canonical = null;  // Hint to the JIT that canonical is unreachable
  
      GcFinalization.awaitClear(signal);
      assertSame(not, pool.intern(not));
    }
  
    public void testAsFunction_simplistic() {
      String canonical = "a";
      String not = new String("a");
  
      Function<String, String> internerFunction =
          Interners.asFunction(Interners.<String>newStrongInterner());
  
      assertSame(canonical, internerFunction.apply(canonical));
      assertSame(canonical, internerFunction.apply(not));
    }
  
    public void testNullPointerExceptions() {
      new NullPointerTester().testAllPublicStaticMethods(Interners.class);
    }
  }