content: /*
   * 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.arrow.vector;
  
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.lang.reflect.Field;
  import java.net.URLClassLoader;
  import org.junit.jupiter.api.Test;
  
  /** Test cases for {@link NullCheckingForGet}. */
  public class TestNullCheckingForGet {
  
    /**
     * Get a copy of the current class loader.
     *
     * @return the newly created class loader.
     */
    private ClassLoader copyClassLoader() {
      ClassLoader curClassLoader = this.getClass().getClassLoader();
      if (curClassLoader instanceof URLClassLoader) {
        // for Java 1.8
        return new URLClassLoader(((URLClassLoader) curClassLoader).getURLs(), null);
      }
  
      // for Java 1.9 and Java 11.
      return null;
    }
  
    /**
     * Get the value of flag {@link NullCheckingForGet#NULL_CHECKING_ENABLED}.
     *
     * @param classLoader the class loader from which to get the flag value.
     * @return value of the flag.
     */
    private boolean getFlagValue(ClassLoader classLoader) throws Exception {
      Class<?> clazz = classLoader.loadClass("org.apache.arrow.vector.NullCheckingForGet");
      Field field = clazz.getField("NULL_CHECKING_ENABLED");
      return (Boolean) field.get(null);
    }
  
    /**
     * Ensure the flag for null checking is enabled by default. This will protect users from JVM
     * crashes.
     */
    @Test
    public void testDefaultValue() throws Exception {
      ClassLoader classLoader = copyClassLoader();
      if (classLoader != null) {
        boolean nullCheckingEnabled = getFlagValue(classLoader);
        assertTrue(nullCheckingEnabled);
      }
    }
  
    /**
     * Test setting the null checking flag by the system property.
     *
     * @throws Exception if loading class {@link NullCheckingForGet#NULL_CHECKING_ENABLED} fails.
     */
    @Test
    public void testEnableSysProperty() throws Exception {
      String sysProperty = System.getProperty("arrow.enable_null_check_for_get");
      System.setProperty("arrow.enable_null_check_for_get", "false");
  
      ClassLoader classLoader = copyClassLoader();
      if (classLoader != null) {
        boolean nullCheckingEnabled = getFlagValue(classLoader);
        assertFalse(nullCheckingEnabled);
      }
  
      // restore system property
      if (sysProperty != null) {
        System.setProperty("arrow.enable_null_check_for_get", sysProperty);
      } else {
        System.clearProperty("arrow.enable_null_check_for_get");
      }
    }
  }
  