Lucene example source code file (TestVirtualMethod.java)

This example Lucene source code file (TestVirtualMethod.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

iae, illegalargumentexception, illegalargumentexception, lucenetestcase, method, override, override, testclass1, testclass2, testclass2, testclass4, testvirtualmethod, testvirtualmethod, virtualmethod

The Lucene TestVirtualMethod.java source code

package org.apache.lucene.util;

/**
 * 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.
 */

public class TestVirtualMethod extends LuceneTestCase {

  private static final VirtualMethod<TestVirtualMethod> publicTestMethod =
    new VirtualMethod<TestVirtualMethod>(TestVirtualMethod.class, "publicTest", String.class);
  private static final VirtualMethod<TestVirtualMethod> protectedTestMethod =
    new VirtualMethod<TestVirtualMethod>(TestVirtualMethod.class, "protectedTest", int.class);

  public void publicTest(String test) {}
  protected void protectedTest(int test) {}
  
  static class TestClass1 extends TestVirtualMethod {
    @Override
    public void publicTest(String test) {}
    @Override
    protected void protectedTest(int test) {}
  }

  static class TestClass2 extends TestClass1 {
    @Override // make it public here
    public void protectedTest(int test) {}
  }

  static class TestClass3 extends TestClass2 {
    @Override
    public void publicTest(String test) {}
  }

  static class TestClass4 extends TestVirtualMethod {
  }

  static class TestClass5 extends TestClass4 {
  }

  public void testGeneral() {
    assertEquals(0, publicTestMethod.getImplementationDistance(this.getClass()));
    assertEquals(1, publicTestMethod.getImplementationDistance(TestClass1.class));
    assertEquals(1, publicTestMethod.getImplementationDistance(TestClass2.class));
    assertEquals(3, publicTestMethod.getImplementationDistance(TestClass3.class));
    assertFalse(publicTestMethod.isOverriddenAsOf(TestClass4.class));
    assertFalse(publicTestMethod.isOverriddenAsOf(TestClass5.class));
    
    assertEquals(0, protectedTestMethod.getImplementationDistance(this.getClass()));
    assertEquals(1, protectedTestMethod.getImplementationDistance(TestClass1.class));
    assertEquals(2, protectedTestMethod.getImplementationDistance(TestClass2.class));
    assertEquals(2, protectedTestMethod.getImplementationDistance(TestClass3.class));
    assertFalse(protectedTestMethod.isOverriddenAsOf(TestClass4.class));
    assertFalse(protectedTestMethod.isOverriddenAsOf(TestClass5.class));
    
    assertTrue(VirtualMethod.compareImplementationDistance(TestClass3.class, publicTestMethod, protectedTestMethod) > 0);
    assertEquals(0, VirtualMethod.compareImplementationDistance(TestClass5.class, publicTestMethod, protectedTestMethod));
  }

  @SuppressWarnings("unchecked")
  public void testExceptions() {
    try {
      // cast to Class to remove generics:
      publicTestMethod.getImplementationDistance((Class) LuceneTestCase.class);
      fail("LuceneTestCase is not a subclass and can never override publicTest(String)");
    } catch (IllegalArgumentException arg) {
      // pass
    }
    
    try {
      new VirtualMethod<TestVirtualMethod>(TestVirtualMethod.class, "bogus");
      fail("Method bogus() does not exist, so IAE should be thrown");
    } catch (IllegalArgumentException arg) {
      // pass
    }
    
    try {
      new VirtualMethod<TestClass2>(TestClass2.class, "publicTest", String.class);
      fail("Method publicTest(String) is not declared in TestClass2, so IAE should be thrown");
    } catch (IllegalArgumentException arg) {
      // pass
    }

    try {
      // try to create a second instance of the same baseClass / method combination
      new VirtualMethod<TestVirtualMethod>(TestVirtualMethod.class, "publicTest", String.class);
      fail("Violating singleton status succeeded");
    } catch (UnsupportedOperationException arg) {
      // pass
    }
  }
  
}